CA2290689A1 - Method and apparatus for preserving food - Google Patents
Method and apparatus for preserving food Download PDFInfo
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- CA2290689A1 CA2290689A1 CA002290689A CA2290689A CA2290689A1 CA 2290689 A1 CA2290689 A1 CA 2290689A1 CA 002290689 A CA002290689 A CA 002290689A CA 2290689 A CA2290689 A CA 2290689A CA 2290689 A1 CA2290689 A1 CA 2290689A1
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- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B7/00—Preservation or chemical ripening of fruit or vegetables
- A23B7/10—Preserving with acids; Acid fermentation
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B4/00—General methods for preserving meat, sausages, fish or fish products
- A23B4/005—Preserving by heating
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B4/00—General methods for preserving meat, sausages, fish or fish products
- A23B4/12—Preserving with acids; Acid fermentation
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B7/00—Preservation or chemical ripening of fruit or vegetables
- A23B7/005—Preserving by heating
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B7/00—Preservation or chemical ripening of fruit or vegetables
- A23B7/06—Blanching
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B9/00—Preservation of edible seeds, e.g. cereals
- A23B9/02—Preserving by heating
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B9/00—Preservation of edible seeds, e.g. cereals
- A23B9/16—Preserving with chemicals
- A23B9/24—Preserving with chemicals in the form of liquids or solids
- A23B9/26—Organic compounds; Microorganisms; Enzymes
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
- A23B9/00—Preservation of edible seeds, e.g. cereals
- A23B9/16—Preserving with chemicals
- A23B9/24—Preserving with chemicals in the form of liquids or solids
- A23B9/30—Inorganic compounds
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/10—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by heating materials in packages which are not progressively transported through the apparatus
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
- A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
- A23L3/34—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals
- A23L3/3454—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by treatment with chemicals in the form of liquids or solids
- A23L3/3463—Organic compounds; Microorganisms; Enzymes
- A23L3/3481—Organic compounds containing oxygen
- A23L3/3508—Organic compounds containing oxygen containing carboxyl groups
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/90—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in food processing or handling, e.g. food conservation
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Zoology (AREA)
- Wood Science & Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Microbiology (AREA)
- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Inorganic Chemistry (AREA)
- Food Preservation Except Freezing, Refrigeration, And Drying (AREA)
Abstract
The present invention is directed to a method of pre-processing food comprising subjecting the food to an environment for a time sufficient to stabilise any unwanted micro-organisms and enzymes present on the food. The present invention is also directed to a method of preserving food which comprises pre-processing the food according to this invention and subjecting the food to preserving process.
Description
~~ f;. ~uv, 19~~ ' i , 5~ N0. 122 ~. ?4 METHOD AND APPARATUS FOR PRESERVING FOOD
The present invention relates to a method of preserving food, particularly meat, vegetables and fruits and products based on meat, vegetables and fruit. It is also directed to food preserved by such a method.
Although the present invention will be described with particular reference to the preparation of meat, vegetable and fruit and products based on these food groups, it will be readily appreciated by the persons skilled in the relevant technology that the scope of the present invention includes food generally, f,orne replacement meals comprising meats and vegetable, bulkfood service portions, unprocessed food such as nuts and pulses, ardd processed foods such as salamis, cheeses, bread, pastries and the like. The scope of the pres~ant inventiore also extends to preservation of food for short term as well as long term storage.
Methods of food preservation commonly used rncfude canning, freeze-drying and irradiation. Vast numbers of chemicals are also used in food preservation not only to preserve thp food but to improve tt~e colour, taste and texture.
However in recent time, consumers h2we become very aware of potential health risks associated with the use of unacceptable chemical additives and certain methods of preservation such as irradiation.
Another popular method of preservation of food is pasteurisation ar steriiisafion ~5 using retort technology. Ret4rt technpi4gy is based on sterilisation of food using heat, for example by heating a product at elevated temperature to destroy vegetative cells and various forms of micro-organisms such as bacteria that cause spoilage.
3D One of the problems associated with this type of food preservation is that application of heat for a minimum amount of time suitable to kill bacteria may cause changes in the food that detract from its appearance. For example, sweet CvY~NW0110V~nlIwWf,7DELE1'E,gPEGESVF000 JOt l v~, Nor, ~~~~ r~?,5a ~~a, ~~142 P
The present invention relates to a method of preserving food, particularly meat, vegetables and fruits and products based on meat, vegetables and fruit. It is also directed to food preserved by such a method.
Although the present invention will be described with particular reference to the preparation of meat, vegetable and fruit and products based on these food groups, it will be readily appreciated by the persons skilled in the relevant technology that the scope of the present invention includes food generally, f,orne replacement meals comprising meats and vegetable, bulkfood service portions, unprocessed food such as nuts and pulses, ardd processed foods such as salamis, cheeses, bread, pastries and the like. The scope of the pres~ant inventiore also extends to preservation of food for short term as well as long term storage.
Methods of food preservation commonly used rncfude canning, freeze-drying and irradiation. Vast numbers of chemicals are also used in food preservation not only to preserve thp food but to improve tt~e colour, taste and texture.
However in recent time, consumers h2we become very aware of potential health risks associated with the use of unacceptable chemical additives and certain methods of preservation such as irradiation.
Another popular method of preservation of food is pasteurisation ar steriiisafion ~5 using retort technology. Ret4rt technpi4gy is based on sterilisation of food using heat, for example by heating a product at elevated temperature to destroy vegetative cells and various forms of micro-organisms such as bacteria that cause spoilage.
3D One of the problems associated with this type of food preservation is that application of heat for a minimum amount of time suitable to kill bacteria may cause changes in the food that detract from its appearance. For example, sweet CvY~NW0110V~nlIwWf,7DELE1'E,gPEGESVF000 JOt l v~, Nor, ~~~~ r~?,5a ~~a, ~~142 P
corn has a relatively high natural sugar content, and the application of heat during sterilisation by retort technology tends to caramelise the sugar, thus altering the corn from its natural yellow colour to a caramel colour. Consumers prefer preserved food to have the same appearance as the corresponding fresh food and often assooiate such a colour change with poor quality.
!t has now been found that presentation of foodstuffs can be greatly improved by a pre-processing step involving lowering the pH of the food. This pre-processing step is carried out before the main food preservation process such as or sterilisation by retort technology. The pre-processing step provides foods on which detrimental micro-organisms and enzymes have been stabilised and when such foods are subjected to a main food preservation process, the final food products are of superior appearance and superior organoleptic qualities compared to foods preserved by preservation techniques of the prior art.
Furthermore the pre-processing step can reduce the processing temperature andlor time spent in the main food preservation process, thus reducing use of energy and reducing the cost of the food preservation process.
In one aspect the present invention provides a method of preserving food comprising;
{i) pre-processing said food comprising bringing said food in contact with an acidufant to lower the pH of the food to around 4.5 or lower to thereby stabilise unwanted micro-organisms and enaymes present on said food said pre-processing being insufficient to sterilize said food;
{ii) packaging said food; and (iii) heating said packaged food to a sufficient temperature and for a sufficient time to sterilise said packaged food.
Throughout this specification, reference to stabilisation of a micro-organism shall mean that propagation andlor growth of the micro-organism is inhibited or completely stopped andlor the micro-organism is rendered more sensitive to ~ ,w ww~ov,r~rwrcoc~sunsc~sauuoo ooc '~~. ~,C'd, 199 ,,~ :~ N~, 1242 r'. 3f being killed during subsequent processing. Throughout this specification, reference to stabilisation of an enzyme shall mean that the enzyme is affected so that it canntrt chemically react with o~ cause detriment to the fond ar its ability to da so is reduced.
The types crf micro-organisms intended to be stabilised include micro-flora and micro-fauna such as bacteria, moulds, fungi, yeast and spares. Nat all rricro organisrns and enzymes are harmfu;. Whilst the present inYentlOrt iS
CIII'ected t0 stabilising unwanted micro-organisms and enzymes, it may affect harmless or beneficial ones as well Ttte types of micro-organism present and the degree of detriment caused wil!
vary from foodstuff to foodstuff. Accordingly the parameter$ of the pre-processing step will vary with the type of food.
h5 Prefierak~ly the acidulant is an organic fold acid such as citric acid, tartaric acid, phosphoric acid or the like. For example it may be present in solution by adding to water 1-5% of said acid, more preferably .5-1% of said acid, based on the total volume of the solution.
za 1t is also preferred that the acidic soution not contain any added salts. That is the acidic solution is not a brine Typically the acidic solution may be used for fruits, such as apples. Apples have ?_5 a naturally high acid content and many of the bacteria associated with apples are adapted to tolerate this acid content. However if the level of acid in the environment surrounding the apple is raised during the pre-processing step of the present invention the remaining baiteria will not propagate.
3a Alternatively, the acidulant may be glucano delta lactose. It is preferable that this acidulant is present in solution and 1,5% glucono delta lactose, mare preferably 1-?% glucono delta lactose may be added to water, based on the total volume of .~.,NAHWOqpv.nw~~.lppE~.E7E5gPEGE81°000 ppC
~E), ~(~~'. ~~yi' 'r~J~ ~~, 122 a, ~!
!t has now been found that presentation of foodstuffs can be greatly improved by a pre-processing step involving lowering the pH of the food. This pre-processing step is carried out before the main food preservation process such as or sterilisation by retort technology. The pre-processing step provides foods on which detrimental micro-organisms and enzymes have been stabilised and when such foods are subjected to a main food preservation process, the final food products are of superior appearance and superior organoleptic qualities compared to foods preserved by preservation techniques of the prior art.
Furthermore the pre-processing step can reduce the processing temperature andlor time spent in the main food preservation process, thus reducing use of energy and reducing the cost of the food preservation process.
In one aspect the present invention provides a method of preserving food comprising;
{i) pre-processing said food comprising bringing said food in contact with an acidufant to lower the pH of the food to around 4.5 or lower to thereby stabilise unwanted micro-organisms and enaymes present on said food said pre-processing being insufficient to sterilize said food;
{ii) packaging said food; and (iii) heating said packaged food to a sufficient temperature and for a sufficient time to sterilise said packaged food.
Throughout this specification, reference to stabilisation of a micro-organism shall mean that propagation andlor growth of the micro-organism is inhibited or completely stopped andlor the micro-organism is rendered more sensitive to ~ ,w ww~ov,r~rwrcoc~sunsc~sauuoo ooc '~~. ~,C'd, 199 ,,~ :~ N~, 1242 r'. 3f being killed during subsequent processing. Throughout this specification, reference to stabilisation of an enzyme shall mean that the enzyme is affected so that it canntrt chemically react with o~ cause detriment to the fond ar its ability to da so is reduced.
The types crf micro-organisms intended to be stabilised include micro-flora and micro-fauna such as bacteria, moulds, fungi, yeast and spares. Nat all rricro organisrns and enzymes are harmfu;. Whilst the present inYentlOrt iS
CIII'ected t0 stabilising unwanted micro-organisms and enzymes, it may affect harmless or beneficial ones as well Ttte types of micro-organism present and the degree of detriment caused wil!
vary from foodstuff to foodstuff. Accordingly the parameter$ of the pre-processing step will vary with the type of food.
h5 Prefierak~ly the acidulant is an organic fold acid such as citric acid, tartaric acid, phosphoric acid or the like. For example it may be present in solution by adding to water 1-5% of said acid, more preferably .5-1% of said acid, based on the total volume of the solution.
za 1t is also preferred that the acidic soution not contain any added salts. That is the acidic solution is not a brine Typically the acidic solution may be used for fruits, such as apples. Apples have ?_5 a naturally high acid content and many of the bacteria associated with apples are adapted to tolerate this acid content. However if the level of acid in the environment surrounding the apple is raised during the pre-processing step of the present invention the remaining baiteria will not propagate.
3a Alternatively, the acidulant may be glucano delta lactose. It is preferable that this acidulant is present in solution and 1,5% glucono delta lactose, mare preferably 1-?% glucono delta lactose may be added to water, based on the total volume of .~.,NAHWOqpv.nw~~.lppE~.E7E5gPEGE81°000 ppC
~E), ~(~~'. ~~yi' 'r~J~ ~~, 122 a, ~!
the solution. It is also preferred that the solution containing glucono delta lactose also not contain any added salts. That is the solution is nct a brine.
The food may be brought into contact with the aciduiar~t in a number of ways.
In 6 a preferred embodiment, where the acidulant is a solution, t~,e food is blanched in the solution.
The blanching may be carrying oufi by bringing the solution to the boil and for a period of 5 seconds to 10 minutes, more preferably 1-4 minutes. After blanching, the food may be removed from the solution and packaged in the absence of any added liquid, such as brine solution.
Preferably, blanching is carried out only for so long as to partially cook said food.
The cooking is then completed in the heating step (iii).
~5 Blanching of thre food will typically be carried oi.~t using an apparatus comprising a processing tank into which the food is Qiaaed, a reservoir for storage of a processing liquid which can be added to the tank and optionally a pump for circulating the liquid in the tank, a heater for heating the liquis~ arid detectorslcontrollprs for monitoring any Changing physical parameters associated yvith the environment created in the tank for E3rocessing the food. The tank may be able to be pressurised with liquid or gas.
In another embodimEnt, the aCidulant either by itself or in solution, is added to the food during a pre-manufacture stage and thereby becomes incorporated as part of the food. For example, in the manufacture of hamburgers, an aciduiant either by itself or in solution, is added to the raw ingredients combined to form the hamburger, 3D Where the acidulant is incorporated into the food, the food may undergo a fr.:u soaking process after step Vii) but before packaging.
~~nnnwwp~.s,nrwwppfi~ETE~iPECnES:wppO.oa:
VG.1242 P. 3~
'~e. lGf, "999 ~?;9 Typically the packaging step comprises hermetically sealing the pre-processed food in a polymeric bag or other suitable polymeric container such as those with sufficient barrier qualities to ensure long shelf I;fe Other containers suitable far processing and storage of the product will be readily apparent to those skilled in 5 the relevant technology.
it is preferred that the food is packaged in a manner so that the package contains air. For example air may be added to the package. Aiternativefy only part of the air already present in the package is evacuated. For example vacuum packaging to about 30% can be undertaken, An advantage of leaving air in the package is that oxygen in the package is toxic to most anaerobic organisms including clostridium botulinus.
l'he packaging step may be a typical canning process, The pre-processing step is not sufficiEnt on its own to preserve the food andlor provide a shelf sable product. Hence a further step is also required.
The additional step may be a sterilising step of the type typically used in the food 2D preparation industry. For example, it may comprise a sterilisation process using heat such as in a retort process ar by heating at ambient pressure, Preferably the food is heated to a temperature between 70°C to 115°C. For food to achieve a certain temperature It is usual that the surrounding environment must be raised to above 5°C above the desired food temperature.
The additions! sterilisation step may be quite simple but the processing parameters wi!I vary from foodstuff to foodstuff. For example food that is not dense may be heated by exposing it to hot water or steam. Food that is dense may require heating at a higher temperature such as in a retor' under pressure.
The following is a description of a p. eferr ed retort process, The foasd is placed irs retort quality barrier bags such as those comprising a film of nylon laminated ' c, "~~C'd, 1 ~ 99 i r : 59 U, 1242 P, 39 between layers of polypropylene. As earlier note, it is preferred that atmospheric air remains within the sealed package sufficient to assist in inhibiting the growth of anaerobic micro-organisms. The bags are then laid out on trays, allowing for bag expansion during processing. The trays are then placed in a retort and the retort 5 secured. The retort is filled with water to a level near a sensor at the top of the inside of the retort. A vapour spa;.e is left for condensation of the heated water.
The blowing of steam into the water is then commenced. A circulation pump is started, sucking water from two inlets at the lowest point of the retort and spraying the water back through an apening at the tap of the retort. The recycle time is 5 minutes The steam blowing is continued until the core ef the foodstuff reaches the desired temperature. The hot water is then pumped ou! and immediately replaced with cold water, reducing the foodstuff temperature to below 55°C, the temperature at whicJ~t the cooking process stops.
Typically, the packaged food is heated in the retort apparatus to a temperature of betuveen 100°C to 115°C for a period of 10-35 minutes at a pressure of 120 kPa to 145 kPa Typiraiiy the apparatus far retort processing comprises a retort in which the food is placed, hot and cold water resertroirs from which. hot and cold water respectively can be pumped into the retort, a boiler for supplying steam to the retork, an air compressor far supplying air to the retort and appropriate sensors and controllers for controlling the supply of water, steam and compressed air to the retort, Alternatively the packaged pre-processed food may be heated using an ambient pressure system such as a bath of boiling water, or heating via a spiral steam cooker.
3D In another embodiment the packaged food may be placed on a conveyor belt which travels slowly through a long closet. In the mentioned closet the packaged food is exposed to heat through the spraying of hot water ar steam at a G uuuWp40WIN~.wO°6Lk'~'Ev6P~G'Eo~OC° DOC
' 6, v0~. 1999 ' ? : g ~~!. ; 242 F. 40 temperature of 95° ;such that the temperature of the packaged food reaches around 90°C) for a certain time period, hater, as the package travels on the conveyer belt the external temperature is reduced to around 90°C (so that the temperature of the packaged food i5 85°G) for a certain time period depending upon the food being processed, At the end of the conveyor belt the bag drops onto a cooling plate where its temperature is quici~ly reduced to ambient.
In a preferred embodiment, the food is heated to a first temperature and then maintained at a second temperature, More preferably the food is heated to a first temperature of about BO°C to 95°G for around 5-15 minutes and then maintained at a second temperature of around 70°C to 95°C for around 5-25 minutes, the whole sterilisation process being carried out at ambient pressure.
It should be noted that the severity of the main preserving ar heating process may be reduced to a level where the main preserving process alone would not provide an acceptable preserved product, but the combination of the pre-processing step plus the main preserving process is suffcient to provide such a product.
Typically the pre-processing step vP the present invention will be used for one particular food or type of food. For example, the pre-processing step may be used to process a batch consisting of a single vegetable such as corn or several different types of vegetables such as corn and peas. T he pre-processed vegetables may then be packaged and sent for further processing or they may be rnixec with other food such as meat, lentils, cereal, flour, rice, pasta ar the !ike, 2.5 and the mixture is then packaged and subjected to further processing.
In another embodiment the present invention is directed to food prr~served by the method of this invention and in packaged form. preferably this food product is a vegetable, fruit, mast or cereal or is formed frr~m a combination of foods ie pasta, c .wuNwureow~H.wao~.ere~aeer~s~o°~.ooc i r, NO'v, i 999 1 ~ ~~ Nu, 1 t42 p Preferably, the method of this invention is used to produce a shelf stable food product. A food product is considered shelf stable if it has a use by date of at least 2 years after its date of manufacture.
The invention will now be further descri5ed by the following non-limiting Examples:
Exam ale 1 The method of the present invention was applied to a food manufactured from a recipe which comprised prime sliced meat, soy sauce, egg, starch, wine, sodium bicarbonate, chilli powder. Chinese pepper, frve spice powder, mono-sodium glutamate and sugar. The recipe was prepared by separating the ingredients into dry ingredients and wet ingredients. The wet ingredients were combined and thoroughly mixed and the pH of the mixture measured at 6.7. At this pH moll micro-organisms will grow prolifically if given sufficient nutrients, moisture, temperaturE and air.
P re-P rocessi ng To stabilise the micro-organisms, fungus, mould ete on the food, the wet ingredients were steamed for two minutes. Such steaming is sufficient to kill most of the surface organisms mentioned before. At this point the proliferation of micro-organisms had been halted and a significant number of micro-organisms had been killed-The pre-processed wet ingredients were then combined with the dry ingredients At this point the pH of the ingredients was lowered by the addition of 1.5°.%
Glucono Delta lactone diluted in an amount of pure water sufFrcient to lower the pH of the total ingredients to 4.3. The ingredients were then portioned and placed in retort barrier bags and hermetically sealed. Care was taken that the bag contained atmospheric air containing oxygen to inhibit anaerobic microbial growth.
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'b. I~OV, 1999 18; ~u ~J0. 1242 '. 42 Sterilisation P'rocesys The plastic retort bags containing the recipe mixture were placed into a retort which was then filled with water. ( It is noted that the same sterilisation can be carried out by filling the retort with hot water). The food was exposed to a temperature of 100 Celsius for 1 C~ minutes at then 90 Celsius for 20 minutes at ambient pressure.
The water was then pumped out of the retort and the retort bags containing the recipe mixture were left to cool over a 5 minute period in the retort before being removed. The food thus prepared was shelf stable and required no refrigeration.
No micro-organism growth could be detected and the food maintained most of the organoleptic properties of the freshly cooked ingredients.
The food recipe prepared by the process of the present invention was compared with the results of processing the same food recipe using a process of the prior art. Tf ~e differences between the process parameters for the two processes are summarised in Table 2;
T~ABLIF 2 Proc~'s of this lnr~ention Prior Art Process Acidification: Yes No Blanching: Yes Sometimes Retort li3a°C for 10 minS 121°C
Temperature: then 90°C for 20 reins Time: 35-45 minutes 70-90 mir~utas Pressure: Ambient 90--95 kPa Packaging: Contains normal air Total vacuum (no air) comparison of the values in Table 2 show that the cur rent process subjects the food to a lower temperature for a far shorter time compared to the process cf the prior art. Accordingly the process of the current invention is riot as harsh on the fr~od and is therefore less likely to damage or change the physical or chemical c urnNwowow~H. woaeeTesa euss.~ooo ooc 'f~, N~'v', 1~'~9 ?~:UC N0, 1242 P, 4:~
structure of the ingredients. The process ef the current invention requires less energy inpu; and is therefore more economicaP than the process of the prior art.
example z 5 Red Kidne~r Bean Pre processing Red Kidney Seans are soakea in hot water far 1 Hr then blanched in boiling water with a soluiivn of .5% Ci;ric Acid for a period of 4 Minutes. The beans are 10 removed frarn the blanching mixture and all liquid allowed to drain off.
Packing The Red kidney Beans are then packed in retort quality barrier bags or other appropriate packaging The beans are not packaged with any brine or liquids.
The package is heat sealed. The packaging rnay be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh 2~ppear2~nce and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
Sterilisation The packages are placed in a retort. Tha retrrt is fPlied with hot water and the temperature is increased to 110C o,rer 7 minutes. Pressure in the retort is kept at 140 kPa. The water in the retort sfays at i iUC for 30 minutes before being quickly cooled by evacuating the hot water and replacing with cald water.
At this stage the product is shelf stable.
C ~M4YVO~IDVnNV...wDGPAETF~EPECIERPDOD.DAC
' ~. NOV. r 9 ~9 ' 8 : i.0 ~C. ' 242 P. 44 Exarn~~le 3 Sweet Corn The sweet corn is de husked and cleaned.
Pre-Processing A blanching solution is prepared by adding to water 1 ~% citric acid. The blanching solution is brought to the boil and the sweet corn is then blanched for 1 minute at boil. The sweet com is removed from the blanching mixture.
Packaging The sweet corn is then packed in retort quality barrier bags or ocher appropriate packaging. The package is heat sealed, The packaging may be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
Sterilisation Because the sweet corn is a dense product requiring a higher degree of heat penetration it requires the sterilisation process to be carried out in a retort.
The packages are placed in a retort, The retort is filled with hot water and after 7 minutes reaches 115C at 140 kPa. The water in the retort is kept at '1150 for minutes before being quickly cooled by evacuating the hot water and replacing with chilled water.
At this stage the product is shelf stable.
c wnrnuorov~.uw~mcre.sPSC~ea~uoo ooc ' ~, ~~'J~~ 199 '.8 . CfJ ~JO. 1242 P. 4F
Example 4 Chicken and Curr)r Dish The above example involved the purchase of a chilled home replacement meal available from a retailer. The meal was tested for its organoleptic qualities and then for its chemical characteristics. The ingredients were found to have a high pH and hence required adjustment to comply with the present process.
Pre-Processing A sofution of 2°Jo by weight of Glucono Oelta l.actone was added to the ingredients sufficient to lower the ingredients pH to 4.3 pH. The addition cf Giucono Delta Lactone did not effect basic organoleptic qualities.
Packaging The chicken and curry meal is then pacr'Ced in retort quality barrier bags or ather appropriate packaging. The paokage is heat sealed. The packaging may be vacuum packed if desired however it is recommended that arey vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
Steritisativn The packaged food is immersed in boiling water ( 100C) far 10 minutes and then left to simmer (90C) for a further 20 minutes. '!-he heated packaging is then immediately Bushed with chilled water sufficient to cool the contents of the package.
At this stage the product is shelf stable.
.~..WY1MNOND1ANN~WC~ELE7EtBPEGIES1FOC0 OOG
The food may be brought into contact with the aciduiar~t in a number of ways.
In 6 a preferred embodiment, where the acidulant is a solution, t~,e food is blanched in the solution.
The blanching may be carrying oufi by bringing the solution to the boil and for a period of 5 seconds to 10 minutes, more preferably 1-4 minutes. After blanching, the food may be removed from the solution and packaged in the absence of any added liquid, such as brine solution.
Preferably, blanching is carried out only for so long as to partially cook said food.
The cooking is then completed in the heating step (iii).
~5 Blanching of thre food will typically be carried oi.~t using an apparatus comprising a processing tank into which the food is Qiaaed, a reservoir for storage of a processing liquid which can be added to the tank and optionally a pump for circulating the liquid in the tank, a heater for heating the liquis~ arid detectorslcontrollprs for monitoring any Changing physical parameters associated yvith the environment created in the tank for E3rocessing the food. The tank may be able to be pressurised with liquid or gas.
In another embodimEnt, the aCidulant either by itself or in solution, is added to the food during a pre-manufacture stage and thereby becomes incorporated as part of the food. For example, in the manufacture of hamburgers, an aciduiant either by itself or in solution, is added to the raw ingredients combined to form the hamburger, 3D Where the acidulant is incorporated into the food, the food may undergo a fr.:u soaking process after step Vii) but before packaging.
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'~e. lGf, "999 ~?;9 Typically the packaging step comprises hermetically sealing the pre-processed food in a polymeric bag or other suitable polymeric container such as those with sufficient barrier qualities to ensure long shelf I;fe Other containers suitable far processing and storage of the product will be readily apparent to those skilled in 5 the relevant technology.
it is preferred that the food is packaged in a manner so that the package contains air. For example air may be added to the package. Aiternativefy only part of the air already present in the package is evacuated. For example vacuum packaging to about 30% can be undertaken, An advantage of leaving air in the package is that oxygen in the package is toxic to most anaerobic organisms including clostridium botulinus.
l'he packaging step may be a typical canning process, The pre-processing step is not sufficiEnt on its own to preserve the food andlor provide a shelf sable product. Hence a further step is also required.
The additional step may be a sterilising step of the type typically used in the food 2D preparation industry. For example, it may comprise a sterilisation process using heat such as in a retort process ar by heating at ambient pressure, Preferably the food is heated to a temperature between 70°C to 115°C. For food to achieve a certain temperature It is usual that the surrounding environment must be raised to above 5°C above the desired food temperature.
The additions! sterilisation step may be quite simple but the processing parameters wi!I vary from foodstuff to foodstuff. For example food that is not dense may be heated by exposing it to hot water or steam. Food that is dense may require heating at a higher temperature such as in a retor' under pressure.
The following is a description of a p. eferr ed retort process, The foasd is placed irs retort quality barrier bags such as those comprising a film of nylon laminated ' c, "~~C'd, 1 ~ 99 i r : 59 U, 1242 P, 39 between layers of polypropylene. As earlier note, it is preferred that atmospheric air remains within the sealed package sufficient to assist in inhibiting the growth of anaerobic micro-organisms. The bags are then laid out on trays, allowing for bag expansion during processing. The trays are then placed in a retort and the retort 5 secured. The retort is filled with water to a level near a sensor at the top of the inside of the retort. A vapour spa;.e is left for condensation of the heated water.
The blowing of steam into the water is then commenced. A circulation pump is started, sucking water from two inlets at the lowest point of the retort and spraying the water back through an apening at the tap of the retort. The recycle time is 5 minutes The steam blowing is continued until the core ef the foodstuff reaches the desired temperature. The hot water is then pumped ou! and immediately replaced with cold water, reducing the foodstuff temperature to below 55°C, the temperature at whicJ~t the cooking process stops.
Typically, the packaged food is heated in the retort apparatus to a temperature of betuveen 100°C to 115°C for a period of 10-35 minutes at a pressure of 120 kPa to 145 kPa Typiraiiy the apparatus far retort processing comprises a retort in which the food is placed, hot and cold water resertroirs from which. hot and cold water respectively can be pumped into the retort, a boiler for supplying steam to the retork, an air compressor far supplying air to the retort and appropriate sensors and controllers for controlling the supply of water, steam and compressed air to the retort, Alternatively the packaged pre-processed food may be heated using an ambient pressure system such as a bath of boiling water, or heating via a spiral steam cooker.
3D In another embodiment the packaged food may be placed on a conveyor belt which travels slowly through a long closet. In the mentioned closet the packaged food is exposed to heat through the spraying of hot water ar steam at a G uuuWp40WIN~.wO°6Lk'~'Ev6P~G'Eo~OC° DOC
' 6, v0~. 1999 ' ? : g ~~!. ; 242 F. 40 temperature of 95° ;such that the temperature of the packaged food reaches around 90°C) for a certain time period, hater, as the package travels on the conveyer belt the external temperature is reduced to around 90°C (so that the temperature of the packaged food i5 85°G) for a certain time period depending upon the food being processed, At the end of the conveyor belt the bag drops onto a cooling plate where its temperature is quici~ly reduced to ambient.
In a preferred embodiment, the food is heated to a first temperature and then maintained at a second temperature, More preferably the food is heated to a first temperature of about BO°C to 95°G for around 5-15 minutes and then maintained at a second temperature of around 70°C to 95°C for around 5-25 minutes, the whole sterilisation process being carried out at ambient pressure.
It should be noted that the severity of the main preserving ar heating process may be reduced to a level where the main preserving process alone would not provide an acceptable preserved product, but the combination of the pre-processing step plus the main preserving process is suffcient to provide such a product.
Typically the pre-processing step vP the present invention will be used for one particular food or type of food. For example, the pre-processing step may be used to process a batch consisting of a single vegetable such as corn or several different types of vegetables such as corn and peas. T he pre-processed vegetables may then be packaged and sent for further processing or they may be rnixec with other food such as meat, lentils, cereal, flour, rice, pasta ar the !ike, 2.5 and the mixture is then packaged and subjected to further processing.
In another embodiment the present invention is directed to food prr~served by the method of this invention and in packaged form. preferably this food product is a vegetable, fruit, mast or cereal or is formed frr~m a combination of foods ie pasta, c .wuNwureow~H.wao~.ere~aeer~s~o°~.ooc i r, NO'v, i 999 1 ~ ~~ Nu, 1 t42 p Preferably, the method of this invention is used to produce a shelf stable food product. A food product is considered shelf stable if it has a use by date of at least 2 years after its date of manufacture.
The invention will now be further descri5ed by the following non-limiting Examples:
Exam ale 1 The method of the present invention was applied to a food manufactured from a recipe which comprised prime sliced meat, soy sauce, egg, starch, wine, sodium bicarbonate, chilli powder. Chinese pepper, frve spice powder, mono-sodium glutamate and sugar. The recipe was prepared by separating the ingredients into dry ingredients and wet ingredients. The wet ingredients were combined and thoroughly mixed and the pH of the mixture measured at 6.7. At this pH moll micro-organisms will grow prolifically if given sufficient nutrients, moisture, temperaturE and air.
P re-P rocessi ng To stabilise the micro-organisms, fungus, mould ete on the food, the wet ingredients were steamed for two minutes. Such steaming is sufficient to kill most of the surface organisms mentioned before. At this point the proliferation of micro-organisms had been halted and a significant number of micro-organisms had been killed-The pre-processed wet ingredients were then combined with the dry ingredients At this point the pH of the ingredients was lowered by the addition of 1.5°.%
Glucono Delta lactone diluted in an amount of pure water sufFrcient to lower the pH of the total ingredients to 4.3. The ingredients were then portioned and placed in retort barrier bags and hermetically sealed. Care was taken that the bag contained atmospheric air containing oxygen to inhibit anaerobic microbial growth.
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'b. I~OV, 1999 18; ~u ~J0. 1242 '. 42 Sterilisation P'rocesys The plastic retort bags containing the recipe mixture were placed into a retort which was then filled with water. ( It is noted that the same sterilisation can be carried out by filling the retort with hot water). The food was exposed to a temperature of 100 Celsius for 1 C~ minutes at then 90 Celsius for 20 minutes at ambient pressure.
The water was then pumped out of the retort and the retort bags containing the recipe mixture were left to cool over a 5 minute period in the retort before being removed. The food thus prepared was shelf stable and required no refrigeration.
No micro-organism growth could be detected and the food maintained most of the organoleptic properties of the freshly cooked ingredients.
The food recipe prepared by the process of the present invention was compared with the results of processing the same food recipe using a process of the prior art. Tf ~e differences between the process parameters for the two processes are summarised in Table 2;
T~ABLIF 2 Proc~'s of this lnr~ention Prior Art Process Acidification: Yes No Blanching: Yes Sometimes Retort li3a°C for 10 minS 121°C
Temperature: then 90°C for 20 reins Time: 35-45 minutes 70-90 mir~utas Pressure: Ambient 90--95 kPa Packaging: Contains normal air Total vacuum (no air) comparison of the values in Table 2 show that the cur rent process subjects the food to a lower temperature for a far shorter time compared to the process cf the prior art. Accordingly the process of the current invention is riot as harsh on the fr~od and is therefore less likely to damage or change the physical or chemical c urnNwowow~H. woaeeTesa euss.~ooo ooc 'f~, N~'v', 1~'~9 ?~:UC N0, 1242 P, 4:~
structure of the ingredients. The process ef the current invention requires less energy inpu; and is therefore more economicaP than the process of the prior art.
example z 5 Red Kidne~r Bean Pre processing Red Kidney Seans are soakea in hot water far 1 Hr then blanched in boiling water with a soluiivn of .5% Ci;ric Acid for a period of 4 Minutes. The beans are 10 removed frarn the blanching mixture and all liquid allowed to drain off.
Packing The Red kidney Beans are then packed in retort quality barrier bags or other appropriate packaging The beans are not packaged with any brine or liquids.
The package is heat sealed. The packaging rnay be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh 2~ppear2~nce and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
Sterilisation The packages are placed in a retort. Tha retrrt is fPlied with hot water and the temperature is increased to 110C o,rer 7 minutes. Pressure in the retort is kept at 140 kPa. The water in the retort sfays at i iUC for 30 minutes before being quickly cooled by evacuating the hot water and replacing with cald water.
At this stage the product is shelf stable.
C ~M4YVO~IDVnNV...wDGPAETF~EPECIERPDOD.DAC
' ~. NOV. r 9 ~9 ' 8 : i.0 ~C. ' 242 P. 44 Exarn~~le 3 Sweet Corn The sweet corn is de husked and cleaned.
Pre-Processing A blanching solution is prepared by adding to water 1 ~% citric acid. The blanching solution is brought to the boil and the sweet corn is then blanched for 1 minute at boil. The sweet com is removed from the blanching mixture.
Packaging The sweet corn is then packed in retort quality barrier bags or ocher appropriate packaging. The package is heat sealed, The packaging may be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
Sterilisation Because the sweet corn is a dense product requiring a higher degree of heat penetration it requires the sterilisation process to be carried out in a retort.
The packages are placed in a retort, The retort is filled with hot water and after 7 minutes reaches 115C at 140 kPa. The water in the retort is kept at '1150 for minutes before being quickly cooled by evacuating the hot water and replacing with chilled water.
At this stage the product is shelf stable.
c wnrnuorov~.uw~mcre.sPSC~ea~uoo ooc ' ~, ~~'J~~ 199 '.8 . CfJ ~JO. 1242 P. 4F
Example 4 Chicken and Curr)r Dish The above example involved the purchase of a chilled home replacement meal available from a retailer. The meal was tested for its organoleptic qualities and then for its chemical characteristics. The ingredients were found to have a high pH and hence required adjustment to comply with the present process.
Pre-Processing A sofution of 2°Jo by weight of Glucono Oelta l.actone was added to the ingredients sufficient to lower the ingredients pH to 4.3 pH. The addition cf Giucono Delta Lactone did not effect basic organoleptic qualities.
Packaging The chicken and curry meal is then pacr'Ced in retort quality barrier bags or ather appropriate packaging. The paokage is heat sealed. The packaging may be vacuum packed if desired however it is recommended that arey vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
Steritisativn The packaged food is immersed in boiling water ( 100C) far 10 minutes and then left to simmer (90C) for a further 20 minutes. '!-he heated packaging is then immediately Bushed with chilled water sufficient to cool the contents of the package.
At this stage the product is shelf stable.
.~..WY1MNOND1ANN~WC~ELE7EtBPEGIES1FOC0 OOG
6, ACV, 1999 ? 8 . G' v~C. 1242 ~. c~
Example 5 auJiflower The cauliflower is cleaned thoroughly and the florets are separated to adequate serving size.
Pre-Processing A blanching solution is prepared containing 1% citric acid. The blanching solution is brought to boil and the cauliflower is blanched for 1 minute. The cauliflower is removed from the blanching solution and then immersed in a bath of 1% sodium meta bisulphate at 45G for 5 minutes.
Packaging The cauliflower is removed from the bath and then packed in retort quality barrier bags or other appropriate packaging. The package is heat sealed. The packaging may be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30°!o to minimise damage, to give a fresh appearance and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
8teriiisation The packaged food is immersed in boiling water for 10 minutes and then left to simmer for a further 1Q minutes. The heated packaging is then immediately flushed with chilled water sufficient to cool the contents of the package.
At this stage the product is shelf stable.
~xamole 6 F~amburaer Ingredients for the manufacture of hamburgers were comf~ined Ingredients may includE beef, Iamb, chicken or any other meat. These are combined with egg, C~tWWYnOIIOt~NAWOOGLEIEIiPEGEi~F3CQ.OGC
'~.E.'4~~V.199~ 1~.)' NC.lc42 P, 4 1~
flour, garlic, diced anion and other minor ingredients such as spices. A
chemical analysis was then completed to find ttte ingrEdients pH level.
Pre-Processing To the hamburger ingredients a solution of Glucono delta lactone was added sufficient to decrease the acid level to a 4.3 The hamburgers were then formed and fried in boiling oil until cooked The hamburgers were taken from the fryer and immediately packed Packaging The hamburgers were then packed in retort quality barrier bags or other appropriate packaging. The package is hAat sealed. The packaging may be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package wontain~ some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms, Sterilisation The packaged food is immersed in boiling water for 1 t7 minutes and then left to simmer for a further zo minutes. The heated packaging is then immediately flushed with chilled water sufficient to coo! the contents of the package.
At this stage the product is shelf stable.
Example 7 Carrot The carrot is cleaned and the skin peeled away. The carrot is then sliced julienne style.
C~~WIMNOFDwwwv.~00GLETE~SPEUEB~F'000 DOG
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Pre-Processing A blanching solution i5 prepared containing 1 % Glucono delta L_actone The blanching solution is brought to the boil and the julienne carrot is then blanched for 1 min~rte at 100C.
Packaging The julienne carrots were removed from the blanching solution and then packed in retort quality barrier bags or other appropriate packaging. The package is heat sealed. The packaging may be vacuum packed if desired however it is 10 recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package contains some levee of atmospheric oxygen fo inhibit growth of anaerobic micro-organisms.
Sterilisation 5 The pacf~aged food is immersed in boiling water for 10 minutes and then left to simmer- for a further 10 minutes. The heated packaging is then immediately flushed with chilled water sufficient to cool the contents of the package.
At this stage the product is shelf stable Throughout the description and claims of this specification, the word "comprise"
and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, components, integers or steps.
It will be appreciated that various modificatior;s can be made to the method and apparatus of this invention without departing from the spirit and ambit of the invention, C Nnrr~pqpw~vAWODE~ETEnSPECIEB~FOOp aCG
Example 5 auJiflower The cauliflower is cleaned thoroughly and the florets are separated to adequate serving size.
Pre-Processing A blanching solution is prepared containing 1% citric acid. The blanching solution is brought to boil and the cauliflower is blanched for 1 minute. The cauliflower is removed from the blanching solution and then immersed in a bath of 1% sodium meta bisulphate at 45G for 5 minutes.
Packaging The cauliflower is removed from the bath and then packed in retort quality barrier bags or other appropriate packaging. The package is heat sealed. The packaging may be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30°!o to minimise damage, to give a fresh appearance and ensure the package contains some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms.
8teriiisation The packaged food is immersed in boiling water for 10 minutes and then left to simmer for a further 1Q minutes. The heated packaging is then immediately flushed with chilled water sufficient to cool the contents of the package.
At this stage the product is shelf stable.
~xamole 6 F~amburaer Ingredients for the manufacture of hamburgers were comf~ined Ingredients may includE beef, Iamb, chicken or any other meat. These are combined with egg, C~tWWYnOIIOt~NAWOOGLEIEIiPEGEi~F3CQ.OGC
'~.E.'4~~V.199~ 1~.)' NC.lc42 P, 4 1~
flour, garlic, diced anion and other minor ingredients such as spices. A
chemical analysis was then completed to find ttte ingrEdients pH level.
Pre-Processing To the hamburger ingredients a solution of Glucono delta lactone was added sufficient to decrease the acid level to a 4.3 The hamburgers were then formed and fried in boiling oil until cooked The hamburgers were taken from the fryer and immediately packed Packaging The hamburgers were then packed in retort quality barrier bags or other appropriate packaging. The package is hAat sealed. The packaging may be vacuum packed if desired however it is recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package wontain~ some level of atmospheric oxygen to inhibit growth of anaerobic micro-organisms, Sterilisation The packaged food is immersed in boiling water for 1 t7 minutes and then left to simmer for a further zo minutes. The heated packaging is then immediately flushed with chilled water sufficient to coo! the contents of the package.
At this stage the product is shelf stable.
Example 7 Carrot The carrot is cleaned and the skin peeled away. The carrot is then sliced julienne style.
C~~WIMNOFDwwwv.~00GLETE~SPEUEB~F'000 DOG
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',6. NOV. 1999 ',8;~)"~
Pre-Processing A blanching solution i5 prepared containing 1 % Glucono delta L_actone The blanching solution is brought to the boil and the julienne carrot is then blanched for 1 min~rte at 100C.
Packaging The julienne carrots were removed from the blanching solution and then packed in retort quality barrier bags or other appropriate packaging. The package is heat sealed. The packaging may be vacuum packed if desired however it is 10 recommended that any vacuum packing should be limited to 30% to minimise damage, to give a fresh appearance and ensure the package contains some levee of atmospheric oxygen fo inhibit growth of anaerobic micro-organisms.
Sterilisation 5 The pacf~aged food is immersed in boiling water for 10 minutes and then left to simmer- for a further 10 minutes. The heated packaging is then immediately flushed with chilled water sufficient to cool the contents of the package.
At this stage the product is shelf stable Throughout the description and claims of this specification, the word "comprise"
and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, components, integers or steps.
It will be appreciated that various modificatior;s can be made to the method and apparatus of this invention without departing from the spirit and ambit of the invention, C Nnrr~pqpw~vAWODE~ETEnSPECIEB~FOOp aCG
Claims (18)
1. A method of preserving food comprising;
(i) pre-processing said food comprising bringing said food in contact with an acidulant to lower the pH of the food to around 4.5 or lower to thereby stabilise unwanted micro-organisms and enzymes present on, said food, said pre-processing being insufficient to sterilize said food;
(ii) packaging said food; and (iii) heating said packaged food to a sufficient temperature and for a sufficient time to sterilise said packaged food.
(i) pre-processing said food comprising bringing said food in contact with an acidulant to lower the pH of the food to around 4.5 or lower to thereby stabilise unwanted micro-organisms and enzymes present on, said food, said pre-processing being insufficient to sterilize said food;
(ii) packaging said food; and (iii) heating said packaged food to a sufficient temperature and for a sufficient time to sterilise said packaged food.
2 The method according to claim 1 wherein said pre-processing step comprises blanching said food in a solution containing said acidulant.
3. A method according to claim 2 wherein said blanching is carried out for a sufficient period of time to partially cook said food, cooking of said food being completed in said heating step.
4. The method according to any one of claims 1 to 3 wherein after step (i) and before step (ii), said food is removed from said solution and is packaged in the absence of any added liquid.
5. The method according to any one of Claims 1 to 4 wherein said solution is not a brine.
6. The method according to any one of claims 1 to 5 wherein said food is blanched for 5 seconds to 4 minutes.
7. A method according to claim 1 wherein said pre-processing step comprises incorporating said acidulant into said food.
8. A method according to claim 7 wherein after step (i) and before step (ii) said food is cooked.
9. The method according to any one of claims 1 to 8 wherein said acidulant is an organic food acid.
10. The method of any one ef claims 1 to 3 wherein the acidulant is glucono delta lactone.
11. The method of any one of claims 1 to 10 wherein said food is packaged in a manner so that said package contains air.
12. The method of any one of claims 1 to 11 wherein during packaging of said food, up to 30% of the air present in the package is removed.
13. The method of any one of claims 1 to 12 wherein during step (iii) the packaged food is heated to a temperature of around 70°C to 115°C.
14. The method of any one of claims 1 to 13 wherein during step (iii) the packaged food is heated to a first temperature of around 80°C to 95°C for around 5-15 minutes and then maintained at a second temperature of around 70°C to 95°C for around 10-25 minutes, said heating being carried out at ambient pressure.
15. The method of any one of claims 1 to 13 wherein during step (iii) the packaged food is heated to a temperature of 100°C to 150°C for a period of 10-35 minutes at a pressure of 120 kPa to 145 kPa.
16. The method of any one of claims 1 to 15 wherein said food comprises meat.
17. Packaged food produced by the method of any one of claims 1-16.
18. Packaged food according to claim 17 wherein paid packaged food has a shelf life of at least two years.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUP06853 | 1997-05-16 | ||
| AUPO6853A AUPO685397A0 (en) | 1997-05-16 | 1997-05-16 | Method and apparatus for preserving food |
| PCT/AU1998/000357 WO1998052421A1 (en) | 1997-05-16 | 1998-05-18 | Method and apparatus for preserving food |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2290689A1 true CA2290689A1 (en) | 1998-11-26 |
Family
ID=3801144
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002290689A Abandoned CA2290689A1 (en) | 1997-05-16 | 1998-05-18 | Method and apparatus for preserving food |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AUPO685397A0 (en) |
| CA (1) | CA2290689A1 (en) |
| WO (1) | WO1998052421A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140272042A1 (en) * | 2013-03-15 | 2014-09-18 | Thomas D. Gillette | Systems and methods for packaging food products |
| WO2018234197A1 (en) * | 2017-06-20 | 2018-12-27 | Tetra Laval Holdings & Finance S.A. | A method of heat-treatment of a product in a sealed container of a packaging material |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI860377A (en) * | 1985-01-28 | 1986-07-29 | American Can Co | FOERFARANDE FOER VAERMEBEHANDLING AV MATBURKAR AV PLAST. |
| CA2052343C (en) * | 1991-06-07 | 1997-11-04 | Fredric G. Bender | Process for treating animal carcasses to control bacterial growth |
| GB9207344D0 (en) * | 1992-04-03 | 1992-05-13 | Vetostar Ltd | Preservation of vegetable foodstuffs |
-
1997
- 1997-05-16 AU AUPO6853A patent/AUPO685397A0/en not_active Abandoned
-
1998
- 1998-05-18 CA CA002290689A patent/CA2290689A1/en not_active Abandoned
- 1998-05-18 WO PCT/AU1998/000357 patent/WO1998052421A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO1998052421A1 (en) | 1998-11-26 |
| AUPO685397A0 (en) | 1997-06-12 |
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