Gail S. H. Baccus-Taylor

Emergence of Salmonella enteritidis Phage Type 4 in the Caribbean: Case-Control Study in Trinidad and Tobago, West Indies

A prospective case-control study involving 46 case patients and 92 age- and neighborhood-matched control subjects was conducted in Trinidad and Tobago (T&T) between March 1998 and May 1999 to determine the etiology, sources, and risk factors for Salmonella enteritidis (SE) infection. SE infection in T&T was found to be associated with the consumption of shell eggs, and in particular raw or undercooked eggs. SE isolates from 30 (88%) of 34 patients and from 9 implicated egg or egg-containing food samples were phage type 4. Homemade eggnog and ice cream, cake batter, and egg-containing beverages were the main raw egg-containing foods, reflecting the cultural practices of the people of T&T. Public health education on the risks of eating raw or undercooked eggs, thorough cooking of all egg dishes, and refrigeration of shell eggs and egg dishes; studies tracing infected eggs to their sources; and testing of flocks of layer chickens for SE are needed to reduce the incidence of this infection.

Assessing Thermal Inactivation of Salmonella on Cooked Broiler Chicken Carcasses in Trinidad and Tobago

Salmonella, zoonotic bacteria normally present in broiler chicken flocks, are a major cause of food-borne ill- ness of known aetiology in Trinidad and Tobago, and in the wider English speaking Caribbean. Although cooking is re- garded as an acceptable method for thermal destruction of these pathogens, consumption of undercooked, and re- contaminated cooked broiler meat remains a common mode of transmission to humans. Since the proportion of under- cooked chicken is largely unknown, an assessment of various cooking methods would serve to prioritise intervention strategies that are required to ensure food safety. Cooking time and temperature for fried, boiled, baked, and grilled cook- ing methods, determined from survey and sampling methods, and D-values from published data were inputs into a modi- fied model. The model was constructed in a Microsoft Excel TM workbook, and simulated using @risk add-in computer software, 100,000 iterations, and Latin Hypercube Sampling. Thermal inactivation of Salmonella on broiler chicken meat occurred during boiling (0%) and frying (0%), but Salmonella survived baking (0.001%) and grilling (0.012%). Differ- ences in the expected value were due to differences in cooking time, temperature, environment, and size of broiler chicken cuts. Air, the heat transfer medium for both baking and grilling may be the most important factor linked to inadequately cooked broiler chicken carcasses.