Potter Food Consumption and Disease Risk

Consumer-Pathogen Interactions
1. Auflage 2006
ISBN: 978-1-84569-202-5
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 472 Seiten

Reihe: Woodhead Publishing Series in Food Science, Technology and Nutrition

The public health impact of foodborne disease in both the developed and developing world is high. Foodborne illness is a major cause of disease and some infections can be fatal. With the rise of globalisation, trends towards minimal processing, and changes in food consumption patterns, the food industry, food safety agencies, and public health officials must coordinate their activities to monitor the interactions between foodborne pathogens and food consumers. This important collection reviews vital issues in the relationship between consumers and foodborne bacteria, viruses and parasites, and surveys how interactions between microorganisms and their human hosts influence foodborne disease.Part one considers factors which increase the risk of exposure to foodborne hazards, exploring issues such as the demographics of our changing population and trends in agricultural management. Part two examines human host factors which influence foodborne disease. It includes chapters on non-specific host defences, immunity to foodborne pathogens and heightened susceptibility to foodborne disease due to underlying illness or pregnancy. The final part of the book reviews the mechanisms used by numerous pathogenic agents to invade, evade, colonise and reproduce in the human host. Quantitative microbiological risk assessment (QMRA), essential for the protection of public health, is also covered.With its distinguished editor and international team of contributors, Food consumption and disease risk: consumer-pathogen interactions will be an essential reference for microbiologists, R&D and QA staff in the food industry. - Considers factors that increase the risk of exposure to foodborne hazards - Examines the human factors that influence disease - Distinguished editor and international team of contributors

Autoren/Hrsg.

Potter, M. A.

Leseproben

1 Introduction to foodborne illness: public health impact, pathogens, and consumers
J.G. Morris, Jr.    University of Maryland, USA 1.1 Introduction
Food is a key element of life. We cannot live without it, yet it also serves as a route by which we can become ill. It is a driver of much of who and what we are. It is in many ways a reflection of social status and living standards: in the most developed countries, we have supermarkets filled with foods from across the globe, brought to our doorstep regardless of season or cost. Food choices are driven by a desire to ‘cut carbs’ or other dietary concerns, with obesity a major societal concern. In the less-developed world, in contrast, there are real concerns about food availability/security, with children threatened by well-recognized risks associated with protein-calorie malnutrition. Interwoven among all of this is the ongoing role of food as a vehicle by which pathogenic microorganisms can be introduced into human hosts, as modified by the evolutionary potential of microorganisms, which allows them to take advantage of very different transmission pathways in developed and developing countries, and today’s rapidly changing environmental and host characteristics. The public health impact of infectious foodborne illness is substantial. In the classic paper by Mead and colleagues published in 1999, the US Centers for Disease Control and Prevention (CDC) estimated that there were 76 million illnesses, 325 000 hospitalizations, and 5000 deaths caused by foodborne disease in the United States each year (Mead et al., 1999). While these estimates may be high, similar ranges have been reported from other major developed countries. For 2002, Australia estimated that there were between 4.0 and 6.9 million cases of foodborne illness per year (OzFoodNet, 2003). England and Wales, for 2000, came up with a much lower estimate of 1.3 million foodborne cases; however, estimated rates of bacterial foodborne illnesses (for which the best data are available) were comparable to those from the United States (Adak et al., 2002). Rates of illness are much more difficult to estimate for the developing world. WHO estimates that in 2000 alone 2.1 million people died from diarrheal diseases (WHO, 2002). While it is not possible to say what percentage of these deaths was due to foodborne illness or how many people were ill for each person who died, in the mélange of transmission routes by which these illnesses and their causative pathogens were acquired, food and water undoubtedly played a major role. These estimates, despite their uncertainties, are sufficient to place foodborne illnesses among the major global public health problems. They also underscore the ongoing difficulties that arise in both developed and developing countries in trying to ‘count cases’. This is due in part to deficiencies in public health infrastructure, which make case identification problematic, at best. In the United States, the foodborne disease surveillance system known as FoodNet was established, in part, to address these concerns, providing intensive, active (and expensive) surveillance for foodborne pathogens in a limited number of defined geographic areas. However, even with this intense surveillance, there is clear undercounting of cases, as reflected in the continued use by CDC of multipliers to come up with estimates of actual disease rates. An even more basic problem arises in identifying the food(s) responsible for transmission of a foodborne pathogen (or even saying that transmission was due to a food). Interventions tend to be product- or food-specific, so development of rational control strategies requires that we be able to attribute cases, and the pathogens that cause them, to specific products or product lines (such as poultry, or produce). While we have a basic idea of where pathogens originate, we are finding that there are limits on the availability of quantitative data on ‘food attribution’, of the type necessary to develop up-to-date risk rankings and risk assessment and management models (Batz et al., 2005). The recognition of the need for interventions to try to prevent foodborne diseases is long-standing, and has led to ongoing efforts to establish regulatory frameworks for disease prevention. Dietary laws, dictated, at least in part, by empiric observations regarding ‘high-risk’ foods, date back to early civilizations, and are preserved today in a number of religious systems, including Jewish Kosher and Moslem Halal law. In the more recent past, concerns about foodborne illness paralleled the migration of increasing numbers of people from rural to urban areas. In the United States, prior to the 1870s, almost all of the food consumed was either made in the home or purchased from neighbors, with the exception of a few staples such as flour. Gradually, however, more and more food came from factories or was shipped long distances to market, so that consumers were unaware of the source of the food, the ways in which it had been processed and handled, or even what it contained (Alsberg, 1970; Roe, 1956). At the same time, ‘competition in sales and in the development of products created incentives for illegal profits through the debasement of manufactured foods and the mislabeling of those products’ (Roe, 1956). Concerns that life expectancy was decreasing in the rapidly growing nineteenth-century cities led to demands for government intervention to control epidemics of disease and assure safe food and water for a population that was increasingly dependent on other people for their provision (Hutt and Merrill, 1991). These demands, in turn, played an important role in the development of the modern public health system, and the associated system of public health laws (including food safety laws) that were put in place in the United States in the early part of the twentieth century. These approaches were guided by the best available science at that time, and were effective in controlling what were perceived in the early 1900s as major problems, including exclusion of dead, diseased, disabled, or dying animals from the food supply; accurate labeling of food products; and monitoring of shellfish growing areas for fecal contamination (NRC, 2003). However, in the past 50 years there have been substantive increases in our understanding of foodborne pathogens and their modes of transmission, which, when combined with the emergence of new problems, have underscored the need for new approaches to the control of foodborne illness. At a regulatory level, these factors have led to the implementation of new, science-based regulatory systems, including the US Department of Agriculture’s Pathogen Reduction: Hazard Analysis and Critical Control Points (HACCP) System (in 1995) and the US Food and Drug Administration’s Seafood HACCP system. While these systems appear to have been effective in decreasing rates of some of the major foodborne diseases, we are far from eliminating the problem and, based on past history, we can fully expect that new pathogens will continue to emerge, or ‘old’ pathogens will re-emerge, moving through new transmission pathways that are opened up by ongoing changes in food production practices. As a classic example of this process, Escherichia coli O157:H7 impinged on the awareness of the scientific and public health community for the first time in 1982, and, in a series of outbreaks in fast food restaurants (and school lunchrooms) became an internationally feared cause of foodborne illness (Riley et al., 1983; Bell et al., 1994; Watanabe et al., 1996). The reasons for its rapid emergence as a major ‘developed world’ pathogen are still not completely clear: contributing factors include its extremely low infectious dose (< 10 microorganisms can cause illness), combined with evolutionary changes in the food industry (Armstrong et al., 1996). The latter includes increasing reliance on high-volume production of ground beef, providing greater opportunities for spread of the microorganism from a single contaminated carcass to a large lot of ground beef; changes in farm and feeding practices, with a greater concentration of cattle in smaller numbers of feedlots; and, for the school outbreaks in Japan, widespread dissemination of what appear to have been contaminated seed lots used in the production of sprouts. This same pattern of emergence of new or newly identified infectious agents, facilitated by changing food production practices, has been seen multiple times. In the early twentieth century, shellfish sanitation regulations in the USA were effective in controlling typhoid fever in shellfish, the purpose for which they were designed. However, the major shellfish-associated pathogens in the past several decades have been Vibrio species, including Vibrio vulnificus (a species identified for the first time in the late 1970s), V. parahaemolyticus (which is currently in the midst of a global pandemic associated with strains carrying a unique set of genetic markers), and non-O1 V. cholerae (Morris, 2003). These species are naturally occurring in shellfish harvest waters, particularly during warm summer months, and their presence does not correlate with fecal coliforms (i.e., current regulatory approaches are ineffective in their control). Economic pressures that led to summer harvesting of oysters have resulted in...