Estimation of pathogenic exposure levels and associated baseline bio-risks in edible terrestrial snails (Achachatina marginata) sold in Nigerian markets

Abstract

This research estimated the pathogenic exposure levels and associated baseline bio-risks in edible terrestrial snails (Achachatina marginata) sold in the Nigerian markets in an attempt to ascertain the probable contribution of contaminated snails to the burden of foodborne illnesses in Nigeria. Identification of bacterial pathogens in the edible snails was performed with phenotypic methods. Baseline probability (risk) of a case of illness caused by the identified pathogens was quantified with the United States FDA-iRisk version 4.0 stochastic software. Findings from this research revealed that there were gross contaminations of the meat surfaces of fresh snails (exposed foot of a snail) with bacterial indicators of hygiene [median viable (TAVC) and enterobacteria (TEC) counts = 7.23 log₁₀ CFU/g and 5.07 log₁₀ CFU/g respectively] and food safety [median presumptive Staphylococci (TSC) count = 4.71 log₁₀ CFU/g]. The unsafe profile of the meat surface was further confirmed by the presence of high concentration (exposure level) of coagulase-positive Staphylococci pathogen [median concentration = 4.17 log₁₀ CFU]. Unlike the meat surface, concentrations of haemolytic (group B) Enterococci pathogen isolated from the viscera of snails were insignificant [median concentration of pathogen = 0 log₁₀ CFU]. Therefore, snail meat surfaces were the main sources of significant risks to potential consumers. This probable significant health consequence was further corroborated by a predicted significant baseline risk which indicated that in the absence of adequate microbial mitigation protocols, 1750 potential human consumers above the age of 3 years were most likely to fall ill per 10000 potential consumers. Thus, there is a need for increased advocacy to ameliorate the baseline risks associated with edible fresh snails sold in Nigerian markets or exported to other markets around the world.

Keywords: Bio-risk, Coagulase-positive Staphylococci, Group B Enterococci, FDA-iRisk software