GB2342273A - Aqueous preservative solution for food comprising ozone and salt - Google Patents

Abstract

An aqueous preservative solution for foodstuffs, particularly shelled hard boiled eggs, comprises a chemical salt solution, such as brine, and ozone. The solution is ozonated to a predetermined degree or has a predetermined amount of ozone dissolved in it prior to coming into contact with the foodstuff. The solution, which is preferably ozonated by having one gas passed through it, can increase the shelf-life of foodstuffs without affecting their organoleptic properties.

Description

Solution for Improving Foodstuff Shelf Life This invention relates to a method for improving the shelf life of perishable foodstuffs, in particular hard boiled eggs, but the invention should not be considered limited thereto. Indeed, it will be understood from the following description that the invention has application to a wide variety of foodstuffs which are currently preserved under liquid and where there is a requirement that the liquid under which said foodstuffs are stored does not significantly impair the taste of the said foodstuff. In the interests of brevity however, the following description is provided with exclusive reference to hard boiled eggs.

Eggs are currently processed in a variety of different ways depending on their ultimate use. In general, however the eggs are either pasturised or hard boiled and stored under a liquid preservative solution. Pasturisation involves heat treating the liquid content of the eggs at 64.4 C for a period of 2'/2 minutes as prescribed by European Food preparation standards, and subsequently filtering the pasturised liquid egg to remove any broken egg shells and transporting said liquid to where it is required in containers which may be any size between'/2kg and 20 tonnes.

In the alternate hard boiling processing method, eggs are boiled for a period of up to 15 minutes, whereafter the eggs are shelled and immediately dropped into a preservative solution. Eggs which are damaged for example by being torn during the peeling step or which are otherwise deformed are often mashed and mixed with mayonnaise and other foodstuffs in which there is no requirement for the whole egg.

This invention has particular application to the preservative solution in which the eggs are stored immediately after having been shelled.

Common preservative solutions currently in used include citric acid, citric brine, brine, and other standard organic acids known to those skilled in the art to have preservative characteristics. All said solutions have disadvantages,. In the case of brine the primary disadvantage is that the shelf life of eggs stored in brine solution may be as small as 4 days. In the case of the organic acids and other solutions mentioned, the shelf life of eggs stored therein may be increased to between 14 and 21 days, but these solutions are disadvantaged in that the acidic nature of the solution has a desiccating effect on the egg which therefore has a drier and less palatable texture. Furthermore, the organic acid solutions may impart a detectable and unsavoury flavour to the egg which is why brine is the favoured preservative solution in many cases.

Henceforth, a container load of eggs leaving the egg processing plant at the end on a Friday must be utilise on Monday of the following week to minimise the risk of any perishing of the eggs.

Additionally, international transport of such eggs has heretofore been limited by the short shelf life. Any preservative solution which could increase the shelf life of eggs stored therein above 4 days would obviously be of great benefit to the industry.

It is an object of this invention to provide an improved liquid preservative solution for foodstuffs which markedly increases the shelf life of said foodstuffs when stored thereunder as compared to the storage of like foodstuffs in currently available preservative solutions.

It is a further object of the invention to provide a liquid foodstuff preservative solution which imparts substantially no flavour to the foodstuff which is detectable on tasting said foodstuff.

According to the invention there is provided a foodstuff preservative solution which has been ozonated to a predetermined degree, or in which a predetermined quantity of ozone has been dissolved.

Preferably the solution is a salt solution.

Preferably the salt solution is brine.

Preferably the salt solution is ozonated by passing gaseous ozone therethrough.

Ozone has previously been widely used in the food industry as a sterilising and bactericidal agent, but until now, its use in a foodstuff preservative solution has not been taught. Recent experiments demonstrated the efficacy of ozonated brine solution as a foodstuff preservative solution, the shelf life of eggs stored therein being increased from 4 days to over 10.

It will be appreciated that although the solution according to the invention is ideally applicable to the preservation of eggs, other foodstuffs, for example vegetables, may be stored therein with analogous increase in shelf life.

A possible explanation for the increase in shelf life of hard-boiled eggs when stored in ozonated brine is provided hereinbelow: Ozone, is a powerful oxidising agent, and is generally unstable in either its gaseous form, or when in solution. As a powerful oxidant, ozone reacts readily with almost all organic compounds with which it comes into contact, and during the reaction is reduced to oxygen.

The specific reactivity of ozone with organic compounds has already been employed in food processing plant to eliminate unsavoury odours which may build up within and without the said plant as a result of the ageing or other degradation of certain foodstuffs. The oxidation reaction of ozone with the organic compounds having these odours neutralises the said odours.

In arriving at the invention, the applicant considered that in general the eggs were effectively sterile after the boiling procedure, and therefore any contamination of the eggs which would increase their proclivity for perishing had to occur on their surface and either during the transfer of the eggs from the receptacle in which they were boiled to the storage container, which may or may not contain brine at that stage, or actually during the storage of the eggs in the preservative solution, or during both these events. It was further considered by the applicant that if an ozonated solution was utilise in the container in which the eggs were to be stored, and that a sufficient quantity of ozone could be dissolved in this solution, then not only would both the surface of the eggs and the container be sterilised, but the solution itself would be also be sterilised, and any bacteria therein neutralised.

Ozone has only a relatively short half-life in solution (about 1/2 hr), but even this period is ensure sufficient sterilisation of the container, egg surface, and solution thus providing the much increased shelf life of products stored therein.

Ozonated water has also been used in industry for sterilising and reducing bacterial levels on implements and equipment used in the processing of food. The use of ozonated solutions in connection with foodstuff preservation has previously not been considered because ozone has a degree of toxicity formerly believed to be detrimental to the health of humans, and furthermore its reactivity with organic compounds suggested to those skilled in the art that a significant degradation in the quality of the foodstuff would arise as a result of contamination with said ozonated solutions. It transpires that neither of these factors has any detrimental impact on either the foodstuff being preserved, or humans, while nevertheless providing a surprising increase in shelf life in foodstuffs stored therein.

Claims (3)

1. CLAIMS 1. A foodstuff preservative solution consisting essentially of a chemical salt/water solution characterised in that the solution is ozonated to a predetermined degree, or has dissolved therein a predetermined quantity of ozone prior to coming into contact with the foodstuff.
2. 2. A solution according to claim 1 characterised in that the salt solution is brine.
3. 3. A solution according to any of the previous claims characterised in that the solution is ozonated by passing gaseous ozone therethrough.