Animal and Human Waste as Vehicles for Cross-Contamination of Imported Foods

This chapter focuses on animal and human wastes as potential sources of contamination of imported foods. The amount of animal and human feces generated on a worldwide basis is enormous. The use of human wastes or wastewater for produce production in developed countries is not allowed or is strictly regulated because of the potential for transmission of enteric pathogens. Although use of highly treated domestic wastewater for food crops to be eaten raw is allowed in some states in the United States, it is seldom practiced because of potential health hazards. Of the enteric bacteria, Salmonella, Campylobacter, and Escherichia coli O157:H7 present the greatest problem because they infect a wide variety of animals besides humans. The occurrence of enteric pathogens in the environment is a reflection of the incidence of infection by the pathogen in a population. For example, various studies have indicated that E. coli O157:H7 is commonly present in animal and human wastewaters at levels of 10 to 100/100 ml of municipal sewage and 100 to 1, 000/100 ml of animal wastewaters and wastewaters from slaughterhouses. The concentrations of pathogens detected in raw sewage are provided in the chapter. Animal wastes and effluents from farming operations, including manures and slurries, are frequently applied to increase the soil fertility of cropland. Multiple contamination sources and pathways pose risks to food safety, with solid and liquid waste handling and irrigation of produce and shellfish production representing major risk factors.