[what is the shelf life of food?]
The latest definition of shelf life in the labeling standard for prepackaged food issued by the Ministry of health on May 13, 2011 is: the period for prepackaged food to maintain quality under the storage conditions specified in the label. During this period, the products are fully suitable for sale and maintain the unique quality that does not need to be stated or has been stated in the label.
How is the shelf life determined
The shelf life of food is determined by the provisions of the Pharmacopoeia and laboratory data. Before formulating the shelf life of a food, it is necessary to analyze the objective quality changes of food, such as microbial test, physical and chemical test and sensory inspection. When conducting microbiological tests, it is often necessary to check E. coli and Staphylococcus aureus. Due to gastrointestinal diseases or food poisoning caused by unclean food, the culprit is usually related microorganisms exceeding the standard.
Physical and chemical tests generally check the turbidity, viscosity, pH and vitamin composition for changes. Sensory inspection refers to the quality evaluation of food color, taste and shape by professional inspectors to judge whether the food has deteriorated. In general, the shelf life of the food is determined by multiplying the number of days that the food starts to taste bad by a coefficient of 0.7-0.8. It can be said that the evaluation of food shelf life in China is still very strict. As long as there is no obvious environmental change or improper storage mode in the sales and circulation link, theoretically, food can be eaten safely within the food shelf life.
[consumers should pay attention to several problems related to the shelf life when purchasing food]:
There are many foods that do not need preservatives. For example, pickled cabbage, vinegar, Baijiu and other high sugar, high salt or high acid foods, food itself has inhibition on biological flora, and achieves natural sterilization, thus greatly prolonging its own storage time. Of course, in order to eat fresh food as much as possible, we should also finish the food as soon as possible within the shelf life of the product label.
For foods such as normal temperature milk, cans and canned drinks, long-term storage without preservatives can also be realized through modern food science and technology such as vacuum, sealing, sterilization and aseptic packaging.
For example, candied fruit and quick-frozen food, due to their little water and low temperature during transportation and storage, bacteria will lack basic biological reproduction conditions, so they can also achieve the purpose of quality assurance without adding preservatives.