Microbiological analysis of 'black pudding', a Trinidadian delicacy and health risk to consumers

Abstract

The prevalences of Salmonella, Escherichia coli and Staphylococcus aureus in black pudding which originated from local vendors and supermarkets in Trinidad were determined. The enterotoxigenicity of S. aureus strains and occurrence of O157:H7 strains amongst E. coli isolates were also investigated. For the 100 black puddings each sampled from supermarkets and vendors, the mean total aerobic plate count (TAPC) per g was 1.8 x 10(7) +/- 1.5 x 10(7) and 1.5 x 10(8) +/- 2.3 x 10(8), respectively. E. coli was isolated from 56 (56.0%) black pudding samples from supermarkets with a mean count per g of 9.2 x 10(6) +/- 7.9 x 10(6) compared to a prevalence of 79% (79 of 100) and mean count per g of 3.2 x 10(7) +/- 4.7 x 10(7) for samples from local vendors. The difference between prevalences was statistically significant (P < or = 0.001; chi 2). Only 1 (2.2%) of 45 strains of E. coli from supermarket-purchased pudding tested, was an 0157:H7 strain compared to 9 (13.6%) of 66 strains of E. coli from vendor-sold black pudding. The difference was not statistically significant (P > or = 0.05; chi 2). Five (5.0%) of 100 black pudding samples from supermarkets yielded Salmonella, with S. ohio being the predominant serotype. For vendor-sold black pudding however, 11 (11.0%) samples were positive for Salmonella with a new serotype, S. unnamed (4,12:d-) being responsible for 50% (6 of 12) of isolates from this source. Forty samples each of black pudding from supermarkets and vendors were all (100.0%) positive for S. aureus with mean counts per g being 3.1 x 10(5) +/- 8.8 x 10(5) and 3.3 x 10(6) +/- 7.7 x 10(6), respectively. Overall, 27 (33.8%) of 80 strains of S. aureus tested were enterotoxigenic producing staphylococcal enterotoxins A(SEA), SEB, SEC, SED or a combination. It was concluded that black pudding poses a high risk to consumers based on the prevalence, microbial load and toxigenicity of the pathogens detected.