AU644579B2 - Meat preservation - Google Patents

Description

OPI DATE 18/04/90 AOJP DATE 24/05/90 APPLN. ID 43017 89

PCT

PCT NUMBER PCT/AU89/00405 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) International Publication Number: WO 90/03118 A23B 4/12, 4/02 Al (43) International Publication Date: 5 April 1990 (05.04.90) (21) International Application Number: PCT/AU89/00405 (81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (European pa- (22) International Filing Date: 19 September 1989 (19.09,89) tent), DK, FR (European patent), GB (European patent), IT (European patent), JP, KR, LU (European patent), NL (European patent), SE (European patent), US.

Priority data: PJ 0685 29 September 1988 (29.09.88) AU Published With international search report.

(71) Applicant (for all designated States except US): MEHECO With international search report.

PROPRIETARY LIMITED [AU/AU]; 41 Gedye Street, Doncaster East, VIC 3109 6 4 (72) Inventor; and Inventor/Applicant (for US only) MOYE, Clarence, James [AU/AU]; 41 Gedye Street, Doncaster East, VIC 3109

(AU).

(74) Agent: DAVY, John, ICI Australia Operations Proprietary Limited, Industrial Property Section, 1 Nicholson Street, P.O. Box 4311, Melbourne, VIC 3001 (AU).

(54)Title: MEAT PRESERVATION (57) Abstract The sheft-life of fresh meat may be extended by the application to the surface of the meat of a solid material which is capable of releasing acetic acid in the presence of moisture. The meat to be treated is preferably substantially dry and sufficient solid material is added to provide from 0.19-1.88 mg/sq.cm. of acetic acid. Preferred compounds are the complexes of acetates and acetic acid, particularly sodium diacetate. Application may be by dusting or electrostatic spray. The method is applicable to any kind of meat (beef, pork, poultry, fish, shellfish) and shelf-lives as determined by the standard plate count procedure can often be more than doubled.

RECEIVED 2 5 'JN 19 C/AU 0 0 4 q 1447/TMcS 1 MEAT PRESERVATION This invention relates to the preservation of meat products.

The marketing potential of a wide range of meat (by which is meant all varieties of animal flesh, including poultry and marine animals) is often limited by shelf life considerations, particularly when the products are to be exported.

Deep freezing is an effective but costly approach to reaching export markets, and quality is invariably affected adversely.

As a consequence, there is great interest in the development of processes to improve the keeping quality of fresh products, non-frozen products.

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WA an/nIiIR Trr 11 i n on nAn yvT V .J, 2 I 0uo7IUUqu One method of meeting this need is to use acetic acid which, in the form of vinegar, has been known as a preservative since ancient times, and has been applied in such processes as pickling.

Microbiological studies of its effectiveness date from more recent times for example the work of Levine A.S. and Fellers C.R. (Bacteriology, Vol. 39.

p. 499 (1940)).

The abovementioned method has resulted from work done in Australia by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and it utilises acetic acid washing to increase the shelf life of chilled fresh vacuum-packed beef and sheep carcasses.

The method involves treating the carcass at C with 1.5% acetic acid and results in an increase of approximately 50% in the shelf-life of the products. This procedure has been accepted by local exporters and foreign importers, and approval for its application with respect to the United States has been given via appropriate food regulations.

The disadvantages of this method include the need to operate at higher than normal ambient temperatures and the requirement for solution treatment of the carcass with resultant requirement for constant monitoring of the acetic acid concentration to ensure that carcass water and exudates do not dilute it and thereby reduce its effectiveness. In addition, an increased shelf-life of approximately 50%, while of benefit, leaves substantial room for further improvement.

There has now been discovered a process which not only overcomes the abovementioned disadvantages but which also allows the attainment of a substantially increased shelf-life. There is therefore provided, according to the present 3 PCTZA 9 0 04 0 -3 invention, a method for the treatment of fresh meat such that Its shelf life is extended, the method comprising applying to the surface thereof a solid material which will liberate acetic acid in the presence of moisture.

As previously indicated, "meat" in the context of this invention refers to any animal flesh suitable for human consumption and is considered to include not only beef, mutton, lamb and pork but also poultry or game birds and marine animals such as fish, shellfish and crustaceans.

The solid material is one which will liberate acetic acid in the presence of moisture. One wellknown substance which will do this is sodium diacetate which on complete dissolution in water is present as a mixture of sodium acetate and acetic acid. This substance is already known and used as a food additive. For example, rope and/or mould in bread, cheese and malt syrups can be controlled by the addition of sodium diacetate to the foodstuff concerned. The use of this substance for grain and silage preservation has also been proposed, as has its use to improve the palatability of animal feed.

A further food-related use is the use to provide the vinegar flavour in various snack foods such as "salt and vinegar"-flavoured potato crisps. In connection with meat, sodium diacetate is known as an additive in some sausage meats (see, for example, "Ordinance on amendment of meat ordinance" ("Verordnung zur Xnderung der Fleisch-Verordnung") of 25th August, 1969 by the Bundesminister fur Gesundheitwesen, Federal Republic of Germany as reported in the "Archiv fUr Lebensmittelhygiene" 20(9) (September 1969) at p.213). However, there Is no known use of, or proposal to use, sodium diacetate in the manner HuBST^LE RECEIVED 3 AU 990 89 /00405 of this invention. Sodium diacetate is preferred for use in this invention as it has the advantage of already being a recognised food additive. It has been declared "generally regarded as safe" by the United States regulatory authorities and is exempted there from residue tolerance limits.

Substances other than sodium diacetate which release acetic acid on exposure to moisture are also useful in this invention. These substances are, like sodium diacetate, "complexes" of monovalent and divalent acetate salts and acetic acid, wherein the acetic acid is believed to be held in the molecule in a manner analogous to the water of crystallisation in a crystalline hydrated salt.

On dissolution, the "complex" readily dissociates and, in the case of sodium diacetate, the result is a solution containing sodium acetate and acetic acid. The acetic acid is present in an approximately equimolar mixture of undissociated and dissociated species due to the production of a buffered medium at a pH approximately equal to the pKa of acetic acid. Depending on the amount of water present, the acetic acid concentration can be very high. In the case of similar compounds, an analogous but not identical situation results, the pH of the buffered medium being different, depending on the nature of the acetate salt.

Thus, typical substances useful in the working of this invention include the ammonium, potassium and calcium analogues of sodium diacetate.

Other substances which are capable of liberating acetic acid may be used in this invetion. For example, certain substances which themsilves do not liberate acetic acid when exposed to moisture do so when used in admixture with another solid substance. For example a mixture of sodium acetate and sodium dihydrogen orthophosphate SUBsTITUTr E "'13 ,f Y OMZAU 8 .9 will liberate acetic acid, whereas sodium acetate used alone will not.

The meat to be coated is preferably substantially dry, by which is meant that no water drips from the hung meat. Many meat products are washed with water prior to storage for transport and for later use, and in the case where meat has been thawed it will naturally have a wet surface; in such cases, it is desirable to remove excess superficial water from the meat, for example, by blowing the water from the meat surface. Minimal water on the meat surface provides a better environment for microbial control in that, when the solid material is coated thereon, there is produced thereon a very effective concentrated mixture of species: in the case of sodium diacetate there is sodium acetate (acting as a buffering agent), acetic acid (in both the molecular and dissociated forms), and sodium diacetate molecules (in the process of dissolution). The natural water content of the meat generally provides sufficient moisture to release acetic acid from the solid material.

The solid material may be applied to the meat in any suitable manner, preferably so as to provide a substantially uniform fine coating. For example, electrostatic coating equipment can be adapted to the application of the present dry material to the meat surface. This is a highly satisfactory method.

For the best results in the case of whole chicken carcass, the geometry of the spraying arrangement is such that the inner cavity of the carcasses receives spray. Alternatively, a dusting box may be used in which the solid material is introduced and maintained in suspension during the residence of the meat within the box. The extent of coating may be gauged by any suitable means. An especially suitable apparatus is described in co-pending

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-6- RECEIVED 1 3 AUG 1990 eCT/AU 8 9 0 0 40 Australian.patent application No. PJ3940. An alternative method is the measuring of surface pH by using a contact pH measuring device.

The solid material should be applied to the surface of the meat to such an extent that on complete liberation of acetic acid, there would be liberated from 0.19 to 1.88 mg acetic acid/sq.cm.

In the case of sodium diacetate, this means that the sodium diacetate should be applied to the extent that the meat receives from 0.5 -5.0 mg solid material/sq cm. Preferably, sodium diacetate should be applied at the rate of from 1-3 mg/sq cm. The solid material applied to the meat may be entirely composed of the acetic acid-releasing substance or it may optionally contain other materials, either inert materials as diluents or materials which alter in some way the properties of the overall material.

Typical materials are free-flow agents such as tricalcium phosphate and calcium silicate, water activity reducing agents such as pre-gelled starch and complementary antimicrobial agents such as the sodium, potassium or calcium salts of sorbic or propionic acid.

When materials additional to the acetic acidreleasing substance are used, it is preferable that the total coating material should be comprised of at least 25% by weight of the substance. It is possible to use less than 25%, but this requires that a very large quantity of material must be applied to achieve the desired effect and this has considerable practical drawbacks.

The method provided by the present invention has numerous advantages over prior art methods used to extend the shelf-life of meat products. In particular, the present method is compatible with the further processing of meat products as currently used such as vacuum and controlled atmosphere packaging. In addition, the current cost of sodium r7 SU3STITUTE SHEET WO 90/03118 PrT/AIIRQ/nlfNAn -7diacetate, coupled with its rate of use, makes the method of this invention economically attractive.

This is particularly so when the simple application technology can be combined with such complementary technologies as specialised packaging systems.

Particular advantages of the present method over the dilute acetic acid treatment developed by CSIRO mentioned hereinabove include the greater effectiveness in reducing microbiological degradation; it is possible to achieve after several days virtually complete elimination of all microorganisms of enterobacterial origin such as salmonella. Further advantages are the ability to use the method for marine products where warm water treatment would generally be considered inappropriate and the convenience of application of the method In situations where the transport and use of acetic acid in glacial or solution form would be inconvenient or hazardous, for example in fishing boats. It has also been found that meats treated in accordance with the present method have a more attractive appearance Immediately after treatment than meat cuts treated by alternative processes.

The invention is further illustrated by the following examples which are not to be construed as limiting the scope of the invention in any way.

WO 90/03118ni Pr/ I AlOn/nnAnr v 8- rJoIU Example 1 This example describes the use of sodium diacetate on beef.

Prime cuts of silverside were obtained the day after slaughter. The meat was sliced into pieces of approximately 1.5 cm thick and of total surface area about 150 sq.cm. These slices were then divided into three series and treated as described below.

Series 1 This was a control series and was left untreated.

Series 2 This was treated according to the CSIRO process previously described, that is, it waq treated by immersion for seconds in 1.5% acetic acid at 55 0

C.

Series 3 This was treated by lowering the temperature of the meat to 8°C, wiping off excess water and dusting the meat on both sides with sodium diacetate by means of a vibrated sieve of aperture 45 um, to the extent of about 5 mg/cm 2 All series were then put in standard Stomacher bags and maintained at 80 10 C. Total plate counts were carried out regularly.

It was found that the Series 1 samples had deteriorated to an unacceptable degree in less than one week. The Series 2 samples reached this unacceptable level after two weeks. The Series 3 results remained acceptable until more than five weeks had passed.

Similar testing on other animal and marine products has shown similar extensions of shelf life over that obtainable from methods known to the art.

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WO 90/ nll 1 DrP A IOQ lnn/i4Ang W UOJA0 O am9D1IA I TOO IUI .J1U 9 1 'II f.u I Example 2 Use of a method according to the invention on chickens.

Substantially dry chicken carcasses from which all internal organs had been removed were suspended by the legs and their exterior surfaces sprayed with sodium diacetate by means of electrostatic spray equipmentto give a level of about 3 mg/sq cm. The carcasses were stored at 2°C and were subjected to regular microbiological testing, there also being included a number of similar carcasses which had not been sprayed.

It was found that the unsprayed carcasses had a shelf life of about 6 days, whereas the sprayed carcasses remained acceptable at 12 days. The tests revealed the presence of salmonella species in all control carcasses and in most of the sprayed carcasses.

The test was repeated with the alteration that an additional spray was directed into the body cavities of the carcasses. Testing revealed the same excellent extension of shelf life with the added attraction that salmonella was absent from most of the carcasses only one carcass in twelve showed the presence of salmonella.

Example 3 Use of a method according to the invention on fish.

Substantially dry rockling fish fillets obtained commercially were dusted with sodium diacetate from a vibrating 45 um sieve to a level of about 3 mg/sq.cm.

lrnJ RECEIVED 1 3 AUG 1990 PCT/AU 0 0 4 0 These fillets were sealed in Stomacher bags as were a number of control (untreated but otherwise similar) fillets. Regular plate counts were taken and these revealed that the control samples had an unacceptable level of microorganisms after 3 days with a standard plate count in excess of 107 counts/g; while after 18 days, the treated fillets standard plate count had still not reached 10 6 counts/g.

Example 4 Use of a method according to the invention on pork.

Slices of pork were treated with sodium diacetate from a vibrating 45 um sieve at two rates, about 1 mg/sq cm and about 3 mg/sq cm. These along with similar but untreated controls were kept in commercial polystyrene trays covered with clear plastics film at 2 C and standard plate counts were taken at regular intervals.

The control samples were unacceptable after 11 days whereas the treated meat (1 mg/sq.cm) samples were unacceptable after 21 days and the treated (3 mg/sq.cm.) samples were still microbiologically acceptable after 23 days.

Example Use of a solid material which is a mixture of sodium acetate and sodium dihydrogen orthophosphate.

Three series of chicken fillets were sprayed with three different solid materials at a rate of about 3 mg/sq.cm. The three solid materials were:sodium diacetate sodium dihydrogen orthophosphate equimolar mixture "of and sodium acetate.

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1 3 01 199UJ 004 0 11 A control series of untreated fillets was not treated in any way.

The fillets were stored at 2°C and regular microbiological testing was carried out. It was found that the control samples were unacceptable after 4 days with a total plate count on day 5 of 8 On day 5, the sodium dihydrogen orthophosphate-treated samples had a plate count in excess of 10 and were also deemed unacceptable.

The fillets treated with the equimolar mixture of sodium acetate and sodium dihydrogen orthophosphate became unacceptable on day 8 and the sodium diacetate-treated fillets became unacceptable on day 9.

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Claims (14)

1. A method for the treatment of fresh meat such that its shelf-life is extended, the method comprising applying to the surface thereof a solid material which will liberate acetic acid in the presence of moisture.

2. A method according to claim 1, wherein the solid material comprises an acetic acid-releasing susbtance selected from complexes of monovalent and divalent acetate salts and acetic acid.

3. A method according to claim 1 or claim 2, wherein the acetic acid-releasing substance is sodium diacetate.

4. A method according to any one of claims 1-3 wherein there is applied to the meat sufficient solid material such that on complete liberation of acetic acid, there will be liberated from 0.19 to 1.88 mg acetic acid/sq.cm.

A method according to claim 3, wherein there is applied to meat sufficient sodium diacetate to give a concentration of from 0.5 -5 mg/cm 2

6. A method according to claim 5, wherein the 2 concentration is from 1-3 mg/cm 2

7. A method according to any one of claims 1-6, wherein the solid material comprises at least one other material in addition to the acetic acid-releasing substance.

8. A method according to any one of claims 1-7, wherein the acetic acid-releasing substance comprises at least 25% by weight of the solid material, I. S -BSTITUT SHEET

9. A wherein the the time of method according to any one of claims 1-8, surface of the meat is ru-Tstantially dry at application of the soliu material thereto.

A solid material when applied to the surface of fresh meat so as to increase the shelf-life thereof, wherein the solid material comprises at least 25% by weight of a substance which will liberate acetic acid in the presence of moisture.

11. A solid material according to claim 10 wherein the substance is sodium diacetate.

12. claim 11, one other releasing A solid material according to claim 10 and wherein the solid material comprises at least material in addition to the acetic acid- substance.

13. A method substantially as described with reference to the examples.

14. A solid material when applied to the surface of fresh meat substantially as described with reference to the examples. ICI AUSTRALIA OPERATIONS PTY LTD 12 OCTOBER 1993 INTRATONAL SARCH RE~PORT II. C.ASSIFICATI OF SU&=JT M&TIM (if several class Inut, rational Application No, PCT/AJ 89/004035 ificat ion symbols appty, indicate alL) 6 According to International Patent Classification (IPC) or to both National Classification and IPC Int. C.A23B 4/1.2t 4/02 11i. FM1.S ECH Minimum Documentation Searched 7 Classification System IClassification Symbols Ip A23B 4/12, 4/02 Documentation Searched other than Minimum Documentation to tlie Extent that such Documents ore Included in the Fields Searched 8 IPC asabv I II. DOMOM 0OSW TO BE ?MMANT 9 Category* citation of Document, iiwith indication, where zippropriate, IRelevant to I of the relevant passages 12 IClaim No 13 X I A, B, 30179/77 (511651) (KABJSHD~E KAISH& U2NO SEIYAKJJ OYO I(1, MEMiUO) 10 May 1979 (10.05.79) See pages 4a to 5 and claims 1, Iand 6. A IAUT, B, 35476/63 (283653) (THE GRIFFTH LABORATORIES lI%.)g I18 March 1965 (18.03.65) I A. I AU, B, 7671/32 (SHKfl, WflIK4SO PROPRIETRY LfE) 22June 1933 I I (22.06.33)I I X IPatents Abstracts of Japan, C-i.57, page 67, JP, A, 58-860 (HE I11 OGWA) 6 Janu~ary 1983 (06.01.83) I A IPatents Abstracts of Japan, C-216, page 103, JP, A, 58-220677 I I (TAIEDA YAMWIfl KOGYD 22 December 1983 (22.12.83)I I X The Ccrndsed Chiemical Dictionary, Ninth Edition, published 1977 I(1-3, 10-3.) I I(Van Nostrn IReinholdCompany, New York, 'Sodiumn I I diacetate' see page 789 *special categories of cited documents: 10 Later document published after the international filing date or priority date I'A, document defining the general state of the and not in conflict with the application but art which is not considered to be of cited to understand the principle or theory I particular relevance underlying the invention E* earlier document but published on or, *X document of particular relevance; the after the international filing date claimed invention cannot be considered novel S Ll document which may throw doubts on priority or cannot be considered .to involve an claim(s) or which is cited to establish the inventive step I pubtication date of another citation or *Y document of particular relevance; the other special reason (as specified) claimed invention cannot be considered to "01 document referring to an oral disclosure, involve an inventive step when the document use, exhibition or other means is combined with one or more other such document pubLished prior to the documents, such combination being obvious to I international. filing date but Later than a person skilled in the art. the priority date claimed &'document member of the same patent family IDate of the Actual Completion of the IDate of Mailing of this International IInternational Search ISearch Report I23 Novmber 1989 (23.11-89) I 9c.' 'e9 (1 International Searching Authority Isignature of Author i,*f Itlier IAustralian Patent Office I R.E. GRANT tL 4 ANE TO THE 1RETI*IAL SEARCH REPORT ON IIUERNATIONAL APPLICATION NO. !CfAU 8/M This Ame~x lists the known "Al publication level patent family memibers relating to the patent ckocuzrnts cited in the abovemntioned internation search report. The Australian Patent Office is in nio way Liable for these particulars which are merely given for the purpose of infoinmtion. Patent Document Cited in Search Patent Family Memb~ers Report AU 30179/77 BE 860793 BE 860794 CA 1096692 CA 1105307 DE 2749750 DE 2749751 FR 2383610 FR 2383615 GB 1566973 GB 1570836 JP 53116315 NL 7712678 NL 7713074 'US 4207350 US 4308281 US 4399150 US 4410547 EMD OF XUNC