United States Patent 3718486

A method and a packaging assembly for packaging foodstuffs which are to be preserved by the application of heat and comprising steps of wrapping the foodstuffs in thin, heat-resistant, gas and liquid-tight bags, evacuating and sealing the bags, depositing one or more sealed bags in receptacles, filling up the receptacle with a heat-transmitting liquid which dampens the movement of the bags within the receptacle and alleviates impact by external forces, and sealing the receptacle, which can then be subjected to heat treatment for the preservation of the food contents.

Application Number:
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Primary Class:
International Classes:
B65D81/20; B65D81/22; (IPC1-7): A23L3/10
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US Patent References:
2380134Method of preserving foods in flexible-walled fluid-tight bags1945-07-10Waters
2044245Packaging foods1936-06-16Irons

Primary Examiner:
Yudkoff, Norman
Assistant Examiner:
Bernstein, Hiram H.
What I claim is

1. A method of packaging foodstuffs for shipping, said method comprising inserting the foodstuff into bags of thin impermeable sheet material resistant to destruction by heat of temperatures of up to about 70° C., evacuating and sealing said bags, packing the bags tightly in an outer container, filling the remaining space of said outer container with a liquid which is substantially inert in relation to the material of the bags and the container and which dampens the movement of the bags within said outer container and tends to avoid damage to the bags by external forces, sealing the outer container, subjecting the total assembly of bags, container and liquid to a heat treatment sufficient for preserving the foodstuff contained therein, and shipping said assembly of the sealed container and bags with the foodstuff being preserved, the liquid which fills the outer container being a liquid which on contact with the foodstuff will develop a distinct discoloration of the foodstuff, the liquid being filled into the outer container at a temperature of at least 50°C.

2. A method according to claim 1 comprising storing the arrangement at a relatively low temperature and wherein the liquid which fills the outer container has a freezing point below the temperature at which the foodstuff is stored.

This invention relates to a method of packaging foodstuffs which are to be subjected to preservation by heat treatment. It is an object of the invention to provide a packaging that secures fulfilment of the most severe requirements for insuring that the finished article will not act as a disease carrier, which is of particular significance in connection with export. This aim has been accomplished in a manner which, moreover, produces a commodity whose appearance is attractive to the consumer and the fat or juice of which has not, to any appreciable degree, been able to escape into the packaging.

For this purpose the food is wrapped in conventional manner in gas and liquid tight bars of thin heat-resistant foil material, the bags are evacuated and sealed in such a manner as to be gas and liquid tight, and one or more bags are deposited in close relationship in an outer packaging, which is then filled with a liquid that is substantially inert with respect to the foil and packaging material and sealed in such a manner as to be gas and liquid tight. In this manner it is possible to preserve the food by heat treatment after it has been packed for transport and there will be no risk of the food's being contaminated by contact with infectious matter before the packaging is opened, for instance in the country to which the commodity has been exported. This is accomplished because the liquid which is placed into the outer packaging acts as a heat transmitting medium so that the heat preservation is carried out with the requisite efficiency. The liquid will not come into contact with the food itself, but serves to protect the bags by damping the movements of the bags against each other caused by shaking during transport and alleviates the impact of external forces. Moreover, the foil of the bags is maintained firmly pressed against the contents so that there will be no room for the escape of fat or juice during the heat treatment or during transport. Moreover, there is the further advantage that a leakage in a bag can readily be ascertained because the liquid in the outer packaging will leak into the bag and cause discoloration of the contents so that it will be evident immediately on the opening of the packaging that the article is no longer in a proper condition, and the damaged bag may easily be removed. A still further advantage is that for long distance transport, larger packagings may conveniently be used, for instance cans, which are substantially cheaper per unit of food than greater numbers of small packagings, whereas the cost of the thin foil bags is a minor item.

The invention thus provides a packaging that is particularly suited for long distance transport, is extremely economical and offers an effective protection of the contents. The user need only remove the wrapping and take out the food, which can be cooked after a simple rinsing and drying, or the bags may be removed from the outer packaging and stored in refrigerating or freezing cabinets as a well packed cooled or deep-frozen article requiring a minimum of space and which can be sold in small quantities, i.e., in the individual bags, and in a manner resembling that of other articles packed in bags and may thus be made highly attractive to the consumer.

Articles preserved in the manner taught by this invention will often be kept in refrigerating or deep-freeze storage for a considerable length of time, for instance during long-time transport, and it will therefore be expedient to fill the packaging with a liquid having a freezing point below zero, preferably below the temperature at which the food-stuffs are to be stored. Hereby it is insured that where the articles, for one reason or the other, are stored at very low temperatures the liquid provided in the packaging will not freeze at the temperature at which the food is stored.

Normally the liquid used for filling the packaging will be water, but other suitable liquids may be used as well. If water is used, the freezing point may easily be lowered, for instance by the addition of sugar, whereby no damage whatever can be done to the product or the packaging. But also anti-corrosive substances may be added to the water, since they cannot get into contact with the food itself.

The extra control referred to above for disclosing the presence of leaky bags may be further improved by using a liquid which on contact with the food will develop a distinct discoloration thereof. When the liquid is water one of the coloring media normally used in the food industry may be used, such as for instance erythrosine, which, in meat for instance, will develop a strong bluish red color. The said method has the further advantage that by filling the liquid into the packaging at a temperature of at least 50° C., preferably between 60° and 70° C., a negative pressure will be produced in a quite simple manner in the packaging and the denting of the packaging will immediately disclose whether the negative pressure has been maintained or a leakage has occurred. This control is known in connection with canned goods, but here the negative pressure is obtained in a particularly simple manner associated with the specific method of packaging.

In the accompanying drawing, the sole FIGURE is a partly sectional view of a container arrangement provided in accordance with the invention.

In the invention which also relates to a packaging for foods or foodstuffs 12 which are to be subjected to heat preservation after packaging, this packaging comprises bags 14 of thin, heat-resistant in the sense that it is resistant to destruction by heat, foil material 10 for receiving the food and an outer packaging 10 in which the filled bags are packed closely together and which is then filled up with a heat-transmitting damping medium consisting of a liquid 18 which is substantially inert with respect to the foil and packaging material. The packaged articles may then be preserved by the application of heat and when finished they will be effectively protected both mechanically and chemically and can be subjected to long and rough transport without being damaged.