Introduction And Definition Of Issues

For the purpose of this chapter, foodborne biological hazards are identified and discussed on the basis of their inclusion into three broad but distinct categories: bacterial, parasitic, and viral. In the United States, these hazards collectively result in millions of illnesses and thousands of deaths annually, with an economic impact estimated at approximately $8.4 billion per year (Mead et al., 1999; Todd, 1989). Clearly, the majority of foodborne diseases remain unreported and undiagnosed, because unknown agents cause an estimated 62 million illnesses and 3200 deaths annually in the United States and, in contrast, only an estimated 14 million illnesses and 1800 deaths involve identified etiology (Mead et al., 1999).

Foods that have traditionally been implicated in disease outbreaks include undercooked meat, poultry, seafood, and unpasteurized milk. More recently, other foods have emerged as vehicles of transmission including internally contaminated eggs, juices, fruits, and sprouts and other vegetables. The emergence of foodborne diseases may be the result of social, economic, and/or biological factors. Currently, the world supports an all-time high human population, including individuals possessing a wide range of susceptibility to pathogens. Variation in susceptibility within the general population has resulted from an increase in the number of persons with weakened immune systems, increases in use of immunosuppressive agents, an increase in the average population age, and a global increase in malnutrition. Additionally, increased global travel, especially in developing countries, and expanding international trade contribute to the introduction and spread of foodborne diseases, and urbanization leads to increased human crowding, resulting in more contact and subsequently increased opportunities for pathogen transmission (Hall, 1997).

Industrial developments and changes in consumer lifestyles and consumer demand have affected food production and processing practices as well as food preparation procedures. Increased numbers of single-parent households and women in the workforce have limited the amount of time available to spend on meal preparation. In response to consumer demands, the food industry is ever increasingly producing foods that are fresher in taste and appearance, minimally processed, and "natural" or free from additives, while at the same time requiring minimal preparation before consumption (Doyle et al., 1997).

The sections that follow identify and review foodborne and waterborne biological hazards that are currently a public health concern. In addition to a brief background discussion, an overview of general characteristics and foodborne illness characteristics and a section on mechanisms of pathogenesis for each pathogen is presented. Discussions regarding regulatory, industrial, and international implications, as well as current and future implications, of foodborne/ waterborne pathogens are also included.

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