Why do pickles become rancid, moldy, and swollen?

Why do pickles become rancid, moldy, and swollen? Quality problems: After some of the finished pickles are stored for a period of time, there will often be problems such as
rancidity, mildew, and swelling bags.

Cause analysis: (1) Poor barrier of packaging materials - the amount of penetration of oxygen and water vapor into the inside of the packaging in the environment is large, causing the growth and reproduction
of residual microorganisms.

Poor compound fastness of composite fastness - the peeling strength of the composite film used in the packaging bag is poor, that is, the composite fastness between the single-layer films in the composite film is poor, especially in the acidic environment of pickles, the phenomenon of composite film delamination is more likely to occur, resulting in the overall barrier of the composite film and other performance declines
.

(2) Poor sealing in the production process of finished product packaging - the sealing of the packaging bag body or heat sealing part is poor, and in the long-term storage process of finished product packaging, it is easy to cause slow air leakage in
finished product packaging.

In particular, the sealing quality of the heat sealing part is poor, such as the heat sealing strength is too low or too high, and the heat sealing strength is uneven, it is more likely to cause deterioration caused by air leakage
.

Incomplete sterilization - that is, there are still some microorganisms left in the finished packaging, which will grow and multiply in large quantities when they encounter the right temperature and humidity environment and oxygen concentration, resulting in swelling bags
.

Testing recommendations: - pay attention to the monitoring
of the main properties of the packaging material such as oxygen transmission, sealing performance (negative pressure method), heat sealing strength, peel strength and so on.

- Selection of packaging materials with high barrier properties or quality improvement
of existing packaging materials.

----------------- Improve the sterilization effect and improve the sealing quality of the heat sealing (that is, the heat sealing effect
).

Typical quality case:—— Test sample: plastic composite film for vegetable packaging (the customer reported that the product was complained of having a swelling bag problem).

——Targeted test items: oxygen transmission, sealing performance (negative pressure method
).

——Test results: In the sealing performance (negative pressure method) test, the finished product did not leak when it was packaged at -89KPa, and the sealing was good; The oxygen transmission of the bag is 600.
3419 cm3/(m2·24h·0.
1 MPa), which is far lower than the average
of excellent products on the market.

Therefore, the low barrier of packaging is an important reason for
the above problems in the product.