Food or edible material: processes – compositions – and products – Processes – Packaging or treatment of packaged product
Reexamination Certificate
1998-08-24
2002-04-16
Bhat, Nina (Department: 1761)
Food or edible material: processes, compositions, and products
Processes
Packaging or treatment of packaged product
C426S412000, C426S129000, C426S130000
Reexamination Certificate
active
06372274
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a packaged product in which an article, such as a bag, pouch, or casing, is used to package a product, such as food. The invention also relates to a process for making the packaged product according to the present invention.
BACKGROUND OF THE INVENTION
Injecting fresh meat with liquid, such as brine, is a means to tenderize the meat. The brine interacts with the muscle proteins, with the resulting liquid mixture exuding from the meat. During packaging, the liquid which is on the surface of such injected meat products is a blend of the injected brine, muscle proteins, and natural juices and blood from the meat product. This liquid blend tends to smear onto the packaging film in the region to be sealed. The liquid blend is difficult to seal through. We have analyzed the seal strength of seals made under various conditions, and have discovered that the strength of seals made through the liquid blend can be even more than 80% less than the strength of seals made without the liquid blend being present in the seal area while the seal is made.
While some processors have successfully solved this weak-seal problem with equipment and line layouts which prevent the liquid blend from depositing on the seal area, other processors continue to have significant problems. Moreover, it has been found that high-shrinking bags exacerbate the seal failure problem. That is, as the bag shrinks, the seal contacts the product which puts pressure on the seal, which can cause seal failure as the seal shrinks tightly up against the product.
One solution to the seal failure problem has been to provide an oversized shrink bag, so that the seal is made far enough from the product that the shrinkage of the bag does not result in the seal contacting the product within the bag. Although this may reduce the seal failure problem, it causes other problems. More particularly, it produces a packaged product of lesser aesthetic value due to excess film extending outward from the product being packaged. Secondly, the excess film provides an envelope which tends to collect juices from the meat product, which are unsightly and also exhibit an accelerated spoilage rate relative to the remainder of the meat product. It would also be desirable to avoid the seal failure problem while also avoiding the problems of diminished aesthetic appearance due to excess film, unsightly juice accumulation in the envelope of the excess film, and reduced shelf life due to accelerated spoilage rates caused by the juice which accumulates in the envelope of the excess film. The inventors of the present invention have arrived at a solution to these problems.
SUMMARY OF THE INVENTION
We have discovered that seal failure rates can be dramatically reduced for the packaging of a boneless meat product in which the meat has been injected with brine, without using an oversized bag and while providing a package in which the film is shrunk tightly against the meat product. We have discovered that bags made from particular films can be sealed through a brine-containing liquid blend, with significantly fewer seal failures even after the film is shrunk tightly against the boneless meat product. Moreover, it has been found that the use of lower shrink tension and/or lower free shrink can assist in reducing the seal failure due to the seal pulling down tightly against the product being packaged during shrinkage of the film after it is sealed around the product. Our invention enables us to package a product using a bag which is sized closer to the size of the product, thereby providing a final packaged product with an appearance which is of greater aesthetic appeal, i.e., versus the use of an oversized bag.
Using a highly abusive test, we have assessed a seal failure rate of about 66 percent using bags which are currently in commercial use for the packaging of brine-injected boneless pork products. However, through the use of bags made from films of particular polymers (especially metallocene-catalyzed ethylene/alpha-olefin copolymers in the seal layer), as well as by providing the film with a relatively low free shrinkage (and/or substantially lesser shrink tension) in a direction which, in general, is perpendicular to the seal made through the liquid blend, we have discovered that we can reduce the seal failure rate to a level as low as 26 percent, using the same highly abusive test. This is a 60 percent reduction in seal failure rate, using a test we believe to be significantly more abusive than the actual conditions of use of the packaged products. In view of the substantial improvement in seal integrity during our highly abusive testing, we believe that in commercial use our packaged products will exhibit a seal failure rate which is a substantial improvement over the seal failure rate currently being experienced in the commercial market.
As a first aspect, the present invention is directed to a packaged product comprising: (A) a boneless food product comprising at least one member selected from the group consisting of meat and cheese, the food product having a free liquid additive thereon; and (B) a film article which is both surrounding and in contact with both the food product and the free liquid. The film article exhibits a Standard Drop Test failure rate of less than 60 percent; more preferably, less than 55 percent; still more preferably, less than 50 percent; yet still more preferably, less than 45 percent; still more preferably, less than 40 percent, still more preferably, less than 35 percent; still more preferably, less than 30 percent; still more preferably, less than 25 percent; still more preferably, less than 20 percent; still more preferably, less than 15 percent.
Preferably, the film article comprises a heat-shrinkable film. Preferably, the film is a multilayer film comprising a seal layer comprising a homogeneous ethylene/alpha-olefin copolymer. Preferably, the film has a thickness of from about 1.5 to 3 mils; more preferably, from about 1.8 to 2.7 mils; still more preferably, from about 2 to 2.4 mils. Preferably, the film has a free shrink at 185° F. of from about 15 to 60 percent in at least one direction; more preferably, from about 20 to 50 percent. Preferably, the film has a shrink tension at 185° F. of from about 50 to 350 pounds per square inch (i.e., “psi”) in a first direction, and from about 300-1000 in a second direction; more preferably, from about 100 to 200 psi the first direction, and from about 360 to 600 psi in the second direction. Shrink tension is measured in accordance with ASTM D 2838, the entirety of which is hereby incorporated by reference thereto.
If the film article is an end-seal bag, preferably the first direction is the machine direction (i.e., longitudinal direction), so that a seal made through the liquid blend is forced against the product by the shrink tension in the first direction. Likewise, if the film article is a side-seal bag, preferably the first direction is the transverse direction. Preferably, the second direction has a shrink tension of at least about 120 percent of the shrink tension of the first direction; more preferably, from about 150 to 2000 percent of the shrink tension of the first direction; still more preferably, from about 150 to 350 percent of the shrink tension of the first direction; and, yet still more preferably, from about 150 to 300 percent of the shrink tension of the second direction.
Preferably, the multilayer film has a seal layer comprising at least one member selected from the group consisting of polyolefin, polyamide, polyester, polyvinyl chloride, and ionomer; more preferably, homogeneous ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer (especially ethylene/vinyl acetate copolymer), and ionomer. Preferably, the seal layer comprises homogeneous ethylene/alpha-olefin copolymer in an amount of at least about 90 weight percent. A particularly preferred seal layer comprises homogeneous ethylene/alpha-olefin copolymer in an amount of about 80 percent, based on layer weight, and linear low densi
Mize, Jr. James A.
Noel David C.
Bhat Nina
Cryovac Inc.
Hurley Jr. Rupert B.
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