Bacteriologic Quality of Some Trinidadian Ready-to-Consume Foods and Drinks and Possible Health Risks to Consumers

Abstract

The bacteriologic quality of 10 ready-to-consume Trinidadian foods and drinks was determined by culturing for Staphylococcus aureus, Escherichia coli, Salmonella spp. and thermophilic Campylobacter spp. The toxigenicity of S. aureus and E. coli strains was determined and the susceptibility of S. aureus isolates to bacteriophages was also investigated. Of a total of 293 food samples tested, 58 (19.8%), 30 (10.2%), and 10 (3.4%) were positive for S. aureus, E. coli, and Salmonella spp., respectively. All samples were negative for Campylobacter but only two food types, chutney and preserved fruits, were negative in all pathogen assays. The sausage known as black pudding (boudin noir) was significantly (P ≤ 0.001; χ2 more contaminated with S. aureus (73.0%) than other foods and was also significantly (P ≤ 0.0l; χ2) more contaminated (43.2%) than all other foods except seamoss (33.3%) and roti (20.0%), where the difference was not significant (P ≥ 0.05; χ2). Black pudding also yielded all 10 strains of Salmonella isolated; the prevalent serotypes were S. agona (4 isolates) and S. derby (3 isolates). All 30 isolates of E. coli were negative for heat-labile enterotoxins (LT) and verotoxins (VT). Of the 58 S. aureus isolates, 33 (56.9%) were susceptible to bacteriophages with 19 (70.4%) of 20 black-pudding and 12 (66.7%) of 18 ice-cream isolates typeable. None of the isolates recovered from local sweets, snow cones, and roti was typeable. Regardless of the food source, strains of S. aureus were most susceptible to phages in various groups (mixed) constituting 21 (63.6%) of 33 strains typeable, followed by phages in groups III (18.2%) and V (15.2%). Twenty-two (37.9%) strains of S. aureus were enterotoxigenic with 8 (13.8%), 5 (8.6%), 13 (22.4%), and 12 (20.7%) strains producing, either singly or mixed, Staphylococcal enterotoxins A(SEA), B(SEB), C(SEC), and D(SED) respectively. It was concluded that black pudding, a local delicacy, poses the greatest health risk to consumers, making it imperative to institute sanitary measures during its production and sale.