1. What is microbiological testing?
Food microbiological testing refers to the determination of the quantity or the existence of a certain type of microorganism in a unit sample according to certain testing procedures and quality control measures.
Microbiological testing of food is to study the species, quantity and nature of microorganisms in food and their influence on human health by using relevant theories and methods of microorganisms.
2. What is the role of microbiology in food industry? What is the purpose of microbiological testing?
The rich nutrients in food provide sufficient material basis for the growth and reproduction of microorganisms, so food is a good culture medium for microorganisms. Therefore, if microorganisms contaminate the food, they are easy to grow and reproduce, which will result in food spoilage, loss of the original nutrients, and the production of harmful and toxic substances. Once people eat the food that is contaminated by microorganisms, all kinds of acute and chronic poisoning, even long-term effects such as carcinogenesis, teratogenesis and mutagenesis will occur. Therefore, the food must be tested for microorganisms before consumption, which is an important means to ensure food quality and food safety, as well as an important content in the food hygiene standards. Food microbiological testing is an essential part of food quality supervision and management:
① It is one of the important indicators to measure the quality of food hygiene, and one of the scientific bases to judge whether the tested food is edible.
② Through food microbiological testing, we can determine the food processing environment and food hygiene environment, make a correct evaluation of the degree of bacterial contamination of food, provide scientific basis for the health management work, and provide prevention and control measures for infectious diseases and food poisoning.
③ Adhering to the implementation of the "prevention first" health policy, food microbiological testing can effectively prevent or reduce food poisoning and zoonoses and ensure the health of people. At the same time, it is of great significance to improve product quality, avoid economic loss and ensure export.
3. How do you test for microbes in food? Can pathogens be detected in food?
Microbiological testing of food samples: Food will be damaged or affected by microorganisms in the environment during production and placement. In some studies, the extent of damage caused by the amount of bacteria in food is regarded as the primary content of food safety testing. In the process of food microorganism testing, microorganisms that are harmful to human health are mainly tested; in the process of food safety testing, there is coexistence phenomenon of multiple microorganisms, so microbiological inspectors need to separate different bacteria before the test, so that the distribution and the number of microorganisms and bacteria can be understood more clearly. The microorganisms and bacteria include the production-type food microorganisms, like microorganisms that cause food spoilagesuch as acetobacter aceti and yeast, like mold and bacteria, and food-borne pathogenic microorganisms such as hemolytic escherichia coli, clostridium botulinum. The control of microorganism in food raw materials and the inspection of microorganism in finished products are important methods to ensure food safety.
Relevant tests for food pathogenic bacteria: Different pathogenic bacteria do harm to people's health to different extents. Take the rice that we often have in our daily life for example, some unscrupulous traders process the moldy rice again and put it back on the market for a second sale. Although the appearance of the reprocessed rice is the same as that of ordinary rice, there is aspergillus flavus, a kind of pathogenic bacterium, in the rice. Reliable information shows that aspergillus flavus is so harmful that if people eat this kind of rice for a long time, the risk of developing cancer is many times higher than normal people. It can be seen that the testing of pathogenic bacteria in food is a key microbiological testing technology to ensure that we can eat safe food, therefore, we conduct quantitative and strict testing of different kinds of pathogenic bacteria. For example, the pathogenic bacteria of dairy products and meat products are mainly aspergillus flavus and escherichia coli, while salmonella, coliform, escherichia coli and aureus are easy to be found in egg products, and clostridium botulinum, clostridium perfringens and bacillus cervicus are inclined to exist in canned food.
4. What are the 3 main types of bacteria found in food?
Indicator bacteria is a similar group of microorganisms in taxonomy or ecology, and can be used to indicate the past or present characteristics of a sample that cannot be directly proved. The testing results of indicator bacteria can evaluate the safety and hygiene of food, which is very important in food testing. Indicator bacteria can be divided into three types:
The first type is used to evaluate the general health quality, contamination level and safety of the tested samples. The most commonly used types are the total number of colonies, mold and yeast count.
The second type refers to the indicator bacteria of fecal contamination, which mainly includes escherichia coli and coliform bacteria, as well as enterococcus and sulfite reducing clostridium. The detection of these bacteria indicates that the samples have been contaminated by human and animal feces, and there is the presence possibility of enteropahtogenic microganism.
The third type is some specific bacteria (such as certain bacteria, some pathogenic bacteria or other indicator microorganisms) that cannot or cannot be easily detected, and the indicator bacteria can indicate the existence possibility of the above bacteria. Therefore, the monitoring of indicator bacteria instead of some specific bacteria has special and different indicative significance at this time.