Potential for prevention of non-O157 Shiga toxin-producingEscherichia colicontamination in traditionally fermented African maize gruel by fermentative probioticLactobacillus plantarum

Summary Non-O157 Shiga toxin-producing Escherichia coli (STEC) are a frequent cause of STEC-related infections such as diarrhoea. Fermentation by presumptive probiotic Lactobacillus plantarum strain B411 isolated from cereal fermentation was investigated to prevent the growth of acid-adapted (AA) and non-acid-adapted (NAA) non-O157 STEC in traditionally fermented maize gruel, a widely used complementary food in Africa. L. plantarum strain B411 possessed probiotic characteristics and antimicrobial activity against selected pathogenic bacteria. Growth of AA and NAA non-O157 STEC strains was substantially inhibited by 3.6 and 4.8 log reductions, respectively, in the maize gruel fermented with the L. plantarum B411, while their growth was only inhibited by 1.0 and 1.2 log reductions, respectively, by traditional fermentation alone. Inclusion of fermentative strains of L. plantarum exhibiting probiotic activity is a feasible method to ensure safety of traditionally fermented African cereal porridges through inhibition of non-O157 STEC.