Mung Bean

1999). The majority of the outbreaks were attributed to contaminated seed. The FDA published guidance for the sprout industry to enhance the safety of sprouted seeds. The guidelines provided information on seed disinfection with 20,000 ppm calcium hypochlorite, as well as procedures for testing spent irrigation water for Salmonella spp. and E. coli 0157:H7 (FDA, 1999).

Shigella sonnei in parsley Prior to 1998, parsley had not been associated with foodborne illness. In 1998, more than 400 cases of shigellosis were reported in three states and two Canadian provinces (CDC, 1998c). In each outbreak, fresh chopped parsley was sprinkled on dishes or was mixed with the food item. A traceback investigation determined that a farm in Mexico or four farms in California were possible sources for the contaminated parsley. The only reservoir for S. sonnei is humans or other primates; therefore, transmission occurs through the fecal-oral route.

Cyclospora cayetanensis in raspberries, lettuce and basil Beginning in 1996, a new foodborne pathogen and food vehicle were associated with foodborne illness. C. cayetanensis is a coccidian parasite that was originally classified in 1993 by Ortega et al. The oocysts of this parasite are believed to be extremely hardy and can survive harsh environmental conditions. Cyclospora oocyts in freshly excreted stools are noninfectious and are believed to require days to weeks outside the host, under favorable environmental conditions (heat and humidity), to sporulate and thus become infectious. In 1996, a multistate outbreak affecting 1,465 people in the U.S. and Canada was associated with Guatemalan raspberries. This clearly demonstrated that food could serve as a vehicle for this pathogen. In 1997, foods other than raspberries were associated with illness. Five outbreaks of cyclosporiasis occurred in the U.S. and Canada that were associated with mesclun lettuce, basil, and raspberries (Herwaldt,

2000). Prior to 1999, Cyclospora had never been detected in an epidemiologi-cally implicated food item. An outbreak of cyclosporiasis occurred in Missouri in the summer of 1999 that was associated with the consumption of chicken pasta salad and tomato basil salad. The food item common to both dishes was basil. A leftover sample of chicken pasta salad was found to contain a Cyclospora oocyst (Lopez et al., 2001).

Listeria monocytogenes in homemade Latin-style fresh soft cheese In the fall of 2000, 12 cases of listeriosis were identified in North Carolina among Hispanics who had eaten homemade Latin-style fresh soft cheese purchased from local markets or from door-to-door vendors (CDC, 2001). Of the 12 cases, 11 were women and one was a 70-year old immunocompromised male. Ten of the women were pregnant, and the resulting Listeria monocytogenes infections resulted in five stillbirths, three premature deliveries, and two infected newborns. The cheese was made from raw milk illegally purchased from a local dairy farm. Fourteen isolates were obtained from patients, cheese samples, and raw milk samples. All fourteen isolates were indistinguishable by PFGE, indicating a common link.


As microorganisms adapt to changing environmental conditions, the industry and government must assess whether new control measures should be pursued. Prior to 1991, it was never thought that the high acid content of unpasteurized juice would allow the survival or growth of foodborne pathogens. In response to numerous outbreaks associated with unpasteurized juice products, new regulations were implemented by the FDA to prevent future outbreaks. These new regulations involved the use of a warning labeling as well as Hazard Analysis Critical Control Point (HACCP) systems (see Part IV). The industry has also developed new means to process and produce food products. Many of these methods utilize technologies that will extend the shelf-life and maintain the fresh characteristics of the food.

International travel has increased tremendously during recent years. It was estimated that by the year 2000, the number of travellers would be in the order of 660 million people. It was also estimated that, depending on the destination, some 20 to 50% of the world travellers may acquire a foodborne infection. This means that between 130 to 330 million people per year may acquire a foodborne infection due to exposure to foodborne pathogens in countries other than their home country.


The continued importance of consumer education cannot be overemphasized. By reinforcing simple food safety messages, the public will begin to change their food handling habits. Also, by notifying the consumer when a problem occurs, such as a foodborne outbreak or a product recall, they may change their eating or purchasing habits. Those individuals who fall into the "at-risk" category are especially vulnerable to foodborne illness and must be educated on foods that one shouldn't eat.


Most countries have systems for reporting notifiable disease, but very few have foodborne disease surveillance programs. On a worldwide basis, very little is known about foodborne disease. Within the U.S., foodborne disease surveillance is conducted by local, state, and federal public health agencies. By identifying outbreaks quickly and determining the source or cause for the outbreak, surveillance allows one to determine early intervention strategies that may be applied to mitigate further illness.


There are two types of emergence associated with foodborne pathogenic microorganisms. One is a true emergence—this is the emergence of a microorganism that had not previously been associated with human illness. The second type—reemergence—is much more common. A microorganism typically associated with a particular type of food, environmental condition, or geographic location will find a new way to cause disease. As food processing changes, microorganisms will continue to adapt in order to survive.


To keep pace with the changing microbial world, we must continue to support and conduct research. As pathogens begin to adapt, change, and find new niches, we must conduct research to understand and control these emerging pathogens. Broad category areas for research include: detection methodology, growth and survival characteristics, microbial ecology, pathogenicity, and control.

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