TRENDS IN FOOD MICROBIOLOGY Hin-chung Wong Department of Microbiology Soochow University _____________________________________________________________ 1. HISTORY OF FOOD MICROBIOLOGY 2. CONVENTIONAL SYLLABUS OF FOOD MICROBIOLOGY. 3. FOOD MICROBIOLOGY IN THE CHANGING WORLD 3.1. International Trade 3.2. Consumers Trends and Communication 3.3. Development of New Technology 3.4. Development of New Ingredients 3.5. Protection food supply against Food Terrorism Event 3.6. Green movement 4. EMERGING OF NEW FOOD-BORNE PATHOGENIC BACTERIA 5. ANTIMICROBIAL RESISTANCE 6. TRENDS IN RESEARCH ABOUT FOOD MICROBIOLOGY 7. TRENDS IN FOOD MICROBIOLOGY EDUCATION 8. REFERENCES _____________________________________________________________ 1. HISTORY OF FOOD MICROBIOLOGY In the 1930s, microbiologists were mainly concerned with food preservation and spoilage. It means the study of natural flora of foods and the spoilage organisms, and killing of microorganisms by various kinds of food preservations, e.g. canning, low temperature, low available water, low pH, or inhibitory chemicals, etc. In the U.S., Foodborne diseases were little heard in the 1940s. However, the only conventional food-poisoning bacteria mentioned in those days were Clostridium botulinum and Staphylococcus aureus, and Salmonella spp. Botulism was known quite clearly because of the works done to save the canning industry. Staphylococcal food poisoning was a frequent problem with cream-filled baked goods, cured ham, various salads, roast fowl, and occasionally, certain types of cheese. Salmonellosis was believed to be transmitted by sick animals. Other highlights in food microbiology are listed in (Table 1)(Foster, 1989). To name a few: 1959 Aflatoxins were discovered in 1959, when thousands of turkey died in Great Britain after eating moldy peanut meal. 1960-1969 Type E botulism caused dealth in the early 1960s. Salmonella continued to be an important pathogen in food. 1970-1979 A new and unfamiliar agent, Escherichia coli O27:H20, which caused outbreak of gastroenteritis in 1971. Disease outbreaks caused by Yersinia enterocolitica and Campylobacter jejuni were heard of near the end of the decade, but received little attention except from specialists in foodborne disease control. 1980-1989 C. jejuni emerged as the leading cause of gastroenteritis in U.S. Y. enterocolitica was also identified in several outbreaks of gastroenteritis, most of them from dairy products. E. coli O157:H7 first appeared in 1982 and ccaused serious outbreaks. Aeromonas hydrophila also was recognized in the early part of the decade as a possible cause of foodborne disease. Beside the conventional V. cholerae and V. parahaemolyticus, other Vibrio species also attrached attention. L. monocytogenes also re-emerged as an important foodborne disease. 2. CONVENTIONAL SYLLABUS OF FOOD MICROBIOLOGY Food microbiology is a course to study the relationship of habitat to occurrence of microorganisms of foods, the effect of environment on growth of various microorganisms in food, the microbiology of food spoilage and food manufacture, the physical, chemical, and biological destruction of microorganisms in foods, the microbiological examination of foodstuffs, and public health and sanitation bacteriology (Anonymous, 1990). The content of textbook "Microbiology of Foods" by Ayres et al. (Ayres et al., 1980) published in 1980 can be divided into the following parts: Part I. General considerations: a general discussion on microorganism occurring in foods and the relationship of methods of food processing and microorganisms. Part II. Fermentations including single cell proteins and some oriental fermentation. Part III. Specific Food Products, on the microbial flora and spoilage of various foods. Part IV. Foodborne Illnesses Other textbooks of food microbiology have similar contents. The emphasis of these authors on different parts can be estimated in term of ratio of pages covering each part to the whole volume (Table 2). A number of emerging foodborne pathogens and the recent development of new detection technologies are not included in these textbooks. Table 2. Comparison of the contents of several textbooks of food microbiology Number of Pages (/whole volume) ________________________________________________________ Textbook Part I Part II Part III Part IV Introduction and Fermentation Various Foodborne Processing Food Diseases ________________________________________________________ Ayres et al. 146 (21%) 102 (15%) 281 (41%) 152 (22%) 1980 Jay, 1984 251 (54%) 32 (7%) 85 (18%) 93 (20%) Frazier and Westhoff, 311 (61%) 87 (17%) 157 (31%) 67 (13%) 1978 Banwart, 325 (66%) 36 (7%) 30 (6%) 102 (21%) 1981 _________________________________________________________ 3. FOOD MICROBIOLOGY IN THE CHANGING WORLD 3.1. International Trade International trade has been growing rapidly. Raw foods and also prepared foods are distributing internationally. Also food industries have been seeking international coorperation and have different plants all over the world and that would enhance the distribution of local foods, e.g. the sales of Chinese or Japanese foods have been rising rapidly in the U.S. Importance of the microbiology of these foods will be increasing. To avoid importing foreign foodborne pathogens or to avoid exporting foods containing pathogens, more intensive monitor of foodborne pathogens is required, e.g. the V. cholerae in exporting aquaculture to Japan, L. monocytogenes in exporting foods to U.S.A. In Taiwan, the introduction of fast-food chain service systems has gradually changed the attitude of the local consumers. Microbiological quality control of the central kitchens of those chain systems is becoming very important. Foodborne infections may increase in the coming years as a consequence of increased globalization of our food supply (Onwulata et al., 2008). 3.2. Consumers Trends and Communication Changes of consumer attitudes are significant (Table 3) since World War II. Women are no longer "traditional"-- a career wife, mother, and shopper. Consumers play less time to prepare food and shifted to emphasis on cost/benefit rather than price alone. Also play more attention on the nutrition/health and well-being perspective (Breidenstein, 1988). Since foodservice operation (restaurants) is becoming more and more important, microbiological quality assurance should be enforced to prevent outbreaks of food poisonings. Residues, cholersterol, salt, sugar, artificial coloring, additives, etc. (Table 4) are the hot topics of food risks to consumers and it is highly affected by the mass communication and education (Jolly et al., 1989). News emphasizes extraordinary events and skews risk perception (Lee, 1989). Perceptions of the public and expert of risks from eating food do not coincide. The experts rank microbial safety, over-nutrition and non-microbial safety (contaminants, natural toxins, agricultural chemicals and food additives) on the top of the rank of hazards, while the public rank pesticides, new food chemicals, familiar hazards (fat and cholesterol, microbial spoilage, junk foods) on the top of this list (Lee, 1989). From the study of foodborne pathogens, we know that foodborne pathogens are widely distributing and it is not realistic to avoid absolutely the contamination of any of these pathogens. What we could do is to minimize the risk of each of these pathogens. So we have to determine the risk of pathogens in different foods under different conditions. The consumption of fruits and vegetables in the U.S. is growing. Fifty years ago, the total annual per capita consumption of fresh, canned, frozen, and dried fruits and vegetables was about 335 lb (fresh-weight basis); in 1985, it was about 406 lb. Between 1970 and 1985, per capita consumption of fruits and vegetables increased by 23%, and fruit juice by 20%. The factors responsible for this growth include new, high-quality products, higher disposable personal income, the desire of health-conscious Americans to include fruits and vegetables in their diet, and improved distribution systems. The U.S. fruit and vegetable processing industry has changed in terms of product mix and total product use. Consumption of most canned fruit and vegetable products has declined, while consumption of frozen and dried products has increased. The growing availability and use of fresh fruits and vegetables year-round has affected the demand or many traditional processed fruit and vegetable products (Pearl, 1990). The shift to "lite" is apparent. People are looking for lower-calorie, lower-fat, lower-salt alternatives in the marketplace. They are also looking for foods perceived to have a high degree of nutrition, such as high-fiber and high-calcium foods. Most importantly, people are changing their food selection patterns to achieve what they perceive to be a "healthier" diet. Grain-based products fit the "new" emerging dietary patterns. They are perceived to be relatively low in calorie, low in fat, high in fiber, and high in complex carbohydrates. Wheat flour consumption in the U.S., on a per capita base, decreased significantly from the early part of the century to the mid-1970s, but from that point on a significant rise is seen. Consumption of rice-based products has been increasing since about 1960 (Leveille, 1988). Public health professionals say the need for light dairy products is clear. Light dairy product is a dairy product which offers a material difference in a nutrition property which is of significant interest to consumers. It is not restricted to "reduced-calorie" dairy