1. Test content At present, the basic requirement of microbiological test for food in China is safety and non-toxicity. When testing food microorganisms, the main contents include three points:

(1) Testing the degree of food contamination, mainly testing the total number of colonies, coliforms and molds in food samples. This inspection method can only judge the pollution degree of the samples, but cannot explain whether there are safety problems in food.

(2) Qualitative inspection of pathogenic bacteria in food means to check whether there are some or more pathogenic microorganisms in food samples. The main pathogenic bacteria for routine inspection are Staphylococcus aureus, Salmonella, Shigella, Listeria monocytogenes, Escherichia coli causing diarrhea, hemolytic streptococcus, Bacillus cereus, Enterobacter sakazakii and Vibrio parahaemolyticus.

(3) The quantitative inspection of pathogenic bacteria in food means to check the quantity of one or more pathogenic microorganisms in food samples, and analyze the harm degree of food samples by combining the inspection results with scientific data.

2. Characteristics of food microbiological examination

(1) Food microbiological examination involves a wide range of microorganisms and many species. It is complicated and demanding to collect samples for microbiological examination of food.

The research objects of food microbial inspection include: a. Food-borne pathogenic microorganisms, which are pathogenic microorganisms of human diseases, infectious diseases of livestock and poultry, and infectious diseases of people and livestock, and these kinds of microorganisms can reach hundreds; B. Microorganisms causing human food poisoning and their toxins; C. microorganisms that cause food spoilage; D. microorganisms in the food industry. It can be said that there are more microbial groups and species in contact with food microbial testing than other professional microbial testing.

(2) The quantity of bacteria to be separated in food is small and the quantity of miscellaneous bacteria is large, which seriously interferes with the inspection work.

In food microbiological examination, the target bacteria, such as pathogenic microorganisms, food poisoning microorganisms and toxins, mainly come from pollution in the process of production, processing, storage, transportation and sales. Among the polluted microorganisms, the number of pathogenic microorganisms is relatively small, but there are a large number of non-pathogenic microorganisms, which is quite different.

(3) The inspection of microorganisms in food has the concept of quantity

In GB4798-94 food hygiene inspection method, the number of some microorganisms has been clearly stipulated, and besides the indicator bacteria of food pollution degree, such as the total number of colonies and coliforms, there are also pathogenic bacteria such as Staphylococcus aureus, Clostridium perfringens and Bacillus cereus that need to be counted. It is not enough to diagnose food poisoning only by qualitative test, but also by quantitative test of pathogenic bacteria. With the development of science and technology, the quantitative test of various pathogenic bacteria will be carried out in an all-round way. Workers in food microbiology inspection must constantly explore and accumulate quantitative inspection of pathogenic bacteria, so that quantitative inspection of other pathogenic bacteria can be carried out as soon as possible.

(4) food microbiological examination needs accuracy and rapidity.

After food is produced, in order to keep its freshness, it usually enters the market as soon as possible and is transferred to consumers, which requires that the inspection results be obtained as soon as possible to ensure the food safety. On the other hand, each batch of food produced on a large scale in factories has a large quantity, and the sampling quantity, sampling method and inspection method directly affect the correctness of inspection and the handling of batch products. If the inspection result is inaccurate, it will cause serious political influence and economic losses. This is a problem that must be paid attention to in food microbial inspection.

(5) Microbiological examination has certain legal nature.

all countries in the world have established inspection laws and regulations for microbial inspection of food. In international exchanges, the inspection methods of microorganisms in food are also clearly defined. In China, the Ministry of Health promulgated the national standard (GB) of the People's Republic of China-Microbiology. The State Commodity Inspection Bureau promulgated the professional inspection standard (ZBX) for import and export inspection. Internationally, the Food Law Committee has also formulated a series of inspection methods. These all specify some inspection procedures and methods for food-related microorganisms. As food microbiological inspectors, they should carry out food microbiological inspection according to the specified requirements, and shall not arbitrarily change other methods. The answer comes from