Introduction to the role and application of food preservatives

Food preservatives have been used in the food industry for a long time as a type of permitted food additive. It is generally divided into four categories: acid preservatives, ester preservatives, inorganic preservatives and biological preservatives, whose role is mainly to prevent food from spoilage and deterioration caused by microbial reproduction during storage and circulation. 

The use of food preservatives is of great value as they can cause spoilage, mould and mildew, change the colour of the food, break down the nutrition, produce off-flavours and produce toxins that are harmful to health. The preservative principle of food preservatives is as follows: to interfere with the enzyme system of microorganisms, disrupting their normal metabolism and inhibiting enzyme activity; to coagulate and denature the proteins of microorganisms, interfering with their survival and reproduction; to change the permeability of the cell plasma membrane, causing the enzymes and metabolic products in their bodies to overflow and cause them to lose their vitality.

The safety factor of preservatives has always been of great concern. According to the definition and regulations of food additives, the production of food preservatives are subject to strict evaluation and toxicity tests to confirm that there is no safety risk to the body before they are allowed to be used. Then, based on this test, a safe range of preservatives is developed, within which the correct use of food preservatives will not cause harm to the body.

According to the preservative principle, preservatives only inhibit bacteria, but their effectiveness in killing them is minimal. Due to the lack of proper understanding of food preservatives, some companies believe that the more preservatives they add, the longer the shelf life of their food will be, thus leading to an excessive amount of preservatives. In fact, preservatives that inhibit bacteria cannot kill bacteria are needed to work with food ingredients and clean production to achieve the shelf life effect of food.

In the production and processing of food, due to the different situations of preservatives in terms of type, nature, scope of use, price and toxicity, the following points should be noted before using them in a rational manner.

1. Before adding preservatives, it should be ensured that the food is completely sterilised and there should not be a large number of organisms present, otherwise the addition of preservatives will not have the desired effect. For example, sodium benzoate, instead of being a preservative, can be a nutrient source for microorganisms to multiply.

2. The toxicity and range of use of various preservatives should be understood and added in accordance with the safe use amount and range of use. For example, sodium benzoate, which is highly toxic, has been banned in some countries and is strictly limited to use in sauces, jams, pickles, canned food and some wines and beverages in China.

Acidic preservatives can only be used in an acidic environment to have a strong preservative effect, but they have little effect in a neutral or alkaline environment, such as sorbic acid and benzoic acid.

Some preservatives are effective against moulds, some against yeast and some against lactic acid and acetic acid bacteria, so you can only grasp the characteristics of the preservative and prescribe the right medicine. In practice, more preservatives are used in the form of compounding for comprehensive preservative preservation.

According to the different types of food processing process, the price and solubility of preservatives should be taken into account, as well as whether there is an impact on the flavour of the food and other factors, and its advantages and disadvantages should be integrated and applied flexibly.