ABSTRACT
Data on foods that are commonly implicated as vehicles of foodbome pathogens are available in national surveillance reports in some developed countries. If such data are unavailable on a local or regional basis, and related operations (e. g., foodservice) are carried out, similar risks ought to occur when the same types of foods are prepared in developing countries. For example, Mexican-style (particularly beans and ground or shredded meats) (9) and Chinese (particularly fried rice) (10) foods are common vehicles of outbreaks of foodbome diseases in the United States (6). These or similar ethnic foods, originally and commonly prepared in homes, small food shops, and restaurants, and by street vendors in one region, are now often produced for more diverse populations in many regions throughout the world. Hence, risks are implied regardless of whether epidemiological data exist to confirm them. Other foods (e. g., gyros or donairs) that are prepared and sold in some countries are implicated occasionally (19). Many other foods because of their composition and preparation practices are potential (if not actual but thus far undetected) vehicles of foodbome illness. Others, however, are quite shelf stable and present a low to negligible risk. (See Ref. 3 for further explanation and clas sification of risks. )
Whether pathogens reach foods depends on raw ingredients, handling, and preparation procedures. Whether any pathogens present survive, depends on the type (e. g., vegetative cells or spore formers) and quantity of contaminants and on the extent of heating, acidification, or other operations intended to inactivate the pathogens or their toxins. Whether survivors or newly acquired contaminants propagate depends on (a) time-temperature exposures, (b) atmosphere (£h) sur rounding the food, (c) characteristics of the pathogen, (d) ratio of total microbial flora to pathogen, (e) and characteristics [e. g., nutrients, pH, water activity (aw), (£h), and natural or added inhibitory substances] of the food.
