Potential health and safety risk of enterotoxin-producing Bacillus species isolated from fermentation effluents discharged into the environment

Abstract

Bacillus species are an important group of bacteria involved in the fermentation processes. Despite their advantages, their implication in foodborne illnesses due to the production of enterotoxins has received little attention. The study sought to detect enterotoxin-producing Bacillus species from effluent spots around maize and African locust bean (ALB) fermentation environments. Fermentation effluent-contaminated spots of maize and ALB processing sites were sampled for Bacillus species. The identified Bacillus species were screened for various enterotoxigenic genes which include non-hemolytic enterotoxin (nheA, nheB, and nheC), hemolysin BL (hblC, hblD) and Bacillus cereus enterotoxin-T (bceT) using specific oligonucleotides. From the 62 identified Bacillus species, 32.26% (95% CI 23.1–41.4%), 40.32% (95% CI 30.7–49.9%), and 38.71% (95% CI 29.2–48.3%) had bceT, hbl, and nhe enterotoxigenic genes respectively. Also, 32.26% (95% CI 23.1–41.4%) of the Bacillus species had all three categories of enterotoxins assayed in this investigation (nhe, hbl, and bceT), and 59.68% (95% CI 50.1–69.3%) of the Bacillus did not encode any of the genes. The presence of enterotoxigenic genes in Bacillus species recovered from maize and ALB processing environments suggests their potential contamination of fermented food products, and by extension, potential threat to human health, if it is not managed adequately.