#3 Microbial Control of Food
Professor Emeritus at Hokkaido University
Advisor at Japan Food Research Laboratories
Microorganisms are deeply involved in the deterioration of quality and safety of food. Microorganisms and food materials are living organisms as well as human beings. They are all subject to change, and in order to ensure a stable supply of safe foods, constant improvement is required. Every activity aimed at ensuring quality of food is called “quality control”.
Microbial control, also known as antimicrobial intervention, is one of the toughest challenges among quality control efforts of most foods. Microbial control is based upon our ancestors’ way of food handling, and new methods have been added to this basis thanks to scientific research and development. Japanese diet includes a variety of fermented foods and this country follows in a long line of microbial control challenges. In fact, as early as in Muromachi Period(1336-1573), sake(Japanese rice wine) was sterilized by heat. Japanese history of microbial control dates back to much earlier than the Pasteur’s discovery.
Various methods of food microbial control have been developed in consideration of target foods, target microorganisms, and the difference in their circumstances. In addition, food cultures have an influence on this development of microbial control methods. As represented by the hurdle technology, some methods adopt multiple principles to control microorganisms. Figure 1 and Table 1 show the classifications of these methods.
Some people dealing with food lose credibility by misusing the microbial control terms. I hope the glossary in Table 2 would be of help. Even if you remove just 1 microorganism out of food leaving one hundred million of them, the act is called “removal”. If you conduct “microbiocide/pasteurization” toward 99% of one hundred million microorganisms in food, still there are one million microorganisms left. Epidemiological studies have revealed that only one hundred severely-pathogenic microorganisms, such as O157 or norovirus, taken in through the mouth could cause a disease. Theoretically speaking, if one O157 or norovirus reaches the intestinal wall of an eater, he or she might become sick. It is indispensable for microbial control of food to consider how and by whom the food at hand will be consumed (i.e. “Vitamin I (love)”).
References (all in Japanese)
Isshiki, K. (2013). Namasyoku no Oishisa to Risuku (Palatability and Risk of eating raw). NTS.
Japanese Society of Food Microbiology (2010). Syokuhin Biseibutsu Jiten (Dictionary of Food Microbiology). Chuohoki Publishing Co., Ltd.