States, measures such as drinking water disinfection, sewage treatment, milk sanitation and pasteurization, and shellfish monitoring have been largely successful. Newly emerging food safety hazards, however, are largely attributed to foodborne zoonoses that do not necessarily cause illness in animals and are therefore difficult to detect. Additionally, new vehicles have been identified, for example, Salmonella enteritidis found inside eggs (and not just on shells) and bacterial contaminants in juices, fruits, and vegetables formerly believed safe. Recently, outbreaks of the so-called “bird flu” have occurred, in which an avian virus is transmitted to humans through handling of birds (e.g., chickens in processing them for food) (Abbott and Pearson, 2004).

Sources of Contamination

Often contaminated water and animal feeds are the source for animals. In many instances these pathogens survive traditional preparation. For example, E. coli O157:H7 can persist in a rare hamburger and Salmonella enteritidis in an omelet or in a raw egg used for salad dressing. Bacteria can be transferred from foods intended to be properly cooked to other foods, such as when salmonella-contaminated chicken juice is on a cutting board that is then used to prepare a salad. Improper food storage can allow the growth of pathogens in food, such as Clostridium botulinum and Staphalococcus aureus.

Although commodity corn and other grain products are strictly and regularly monitored at multiple processing stages, including mills, dairy facilities, and by regulators, practically all corn or corn products contain at least tiny amounts of fungal mycotoxins. In a recent report, 363 samples of cereal-based infant food were tested, and 100 percent were found to carry various mycotoxins (Lombaert et al., 2003). Consumer illnesses, however, have not been directly attributed to these small amounts of mycotoxin exposure.

Although the potential exists for mycotoxins to reach hazardous levels, the level of monitoring makes it highly unlikely for a contamination event at hazardous levels to occur. Contaminated lots are identified and discarded, obviating the need for a recall. In a recent report for the UK Food Standards Agency, two loads of organic corn meal were prevented from being sold to consumers because of excessive levels of fumonisins, a type of mycotoxin (FSA, 2003).

On occasion, a food processing plant is a source of contamination with either a biological (e.g., E. coli) or nonbiological (e.g., mycotoxin) contaminant. These events may be due to the inadvertent introduction of the contaminant or to a breakdown in the usual monitoring and control systems. When recognized, such events either are corrected before consumers are exposed to a potentially hazardous food or recalled by regulatory agencies (the U.S. Department of Agriculture’s Food Safety and Inspection Service and the U.S. Department of Health and Human Services, Food and Drug Administration).



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