Salmonellosis in Trinidad: evidence for transovarian transmission of Salmonella in farm eggs.

The aim of this study was to determine whether the contents of farm eggs in Trinidad are contaminated with Salmonella and if transovarian transmission occurs. 750 fresh eggs from 10 farms supplying 75% of the country's eggs were cultured for Salmonella. Salmonella was found on the egg shells' surfaces from all farms, and in the egg contents from three farms. Isolates were obtained from the cultures of the contents and shells of nine (1.2%) and 35 (4.66%) eggs, respectively (p < 0.005). Serotypes found in the contents were S. enteritidis (0.8%; deduced to be contaminated by transovarian transmission) and S. typhimurium (0.4%); those isolated from the shells (contaminated by faecal transmission) were S. typhimurium (3.06%), S. enteritidis (0.67%), S. ohio (0.27%), S. cerro (0.27%), S. infantis (0.27%) and S. heidelberg (0.13%). This study provides the first evidence for Salmonella and, more importantly, S. enteritidis, in eggs in Trinidad. This is of major public health significance because S. enteritidis infected eggs appear normal and the organism is difficult to detect and control. The consumption of these eggs may increase the risk of Salmonella infection. Food safety practices, particularly the thorough cooking (> or = 70 degrees C) of all egg dishes and the refrigeration (< 10 degrees C) of shell eggs and egg dishes, are recommended.