title: Prevalence and fate of Bacillus cereus in African traditional cereal-based foods used as infant foods.
abstract: The objective of the present work was to estimate the prevalence of Bacillus cereus group species in traditional cereal-based lactic acid-fermented slurries and nonfermented flours used to prepare infant foods in an African context. High counts on mannitol-egg yolk-polymixin  agar medium were determined for the fermented slurries (median, 4.5 × 10(4) CFU/ml of slurry) compared with the nonfermented flours, most of whose counts were lower than 10(-1) CFU/g. Virulence genes were characterized in 60 isolates from 26 traditional cereal-based  foods in Ouagadougou (Burkina Faso). Seventy-two and 38 % of isolates were positive for the complete set of genes coding for hemolysin BL and nonhemolytic enterotoxin, respectively, suggesting a high enterotoxigenic potential for these foodborne isolates. No potentially emetic toxin-producing  strains were detected. Because of the high counts found for fermented slurries, survival tests with vegetative cells inoculated in fermented slurries were performed, which showed that growth of B. cereus was inhibited. This result suggests that fermentation in traditional production  units is presumably not adequately controlled, enabling growth during any unit operations before fermentation, or even during the fermentation step, when the process was poorly controlled. However, adding nisin (0.1 mg/ml) enabled a 5-log reduction in the B. cereus population in 5 h,  suggesting that the use of nisin could be a way to upgrade the hygienic quality of this type of food.
authors.affiliation: Institut de Recherche pour le Développement, UMR Nutripass, Université Montpellier 1-Université Montpellier 2, Montpellier, France.
authors.forename: Christèle
authors.initials: C
authors.lastname: Humblot
authors.forename: Ruben
authors.initials: R
authors.lastname: Perez-Pulido
authors.forename: David
authors.initials: D
authors.lastname: Akaki
authors.forename: Gérard
authors.initials: G
authors.lastname: Loiseau
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Guyot
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects / Q000302:isolation & purification*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D002523:Edible Grain / Q000382:microbiology*; D005285:Fermentation; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000382:microbiology*; D009561:Nisin / Q000494:pharmacology*; D015995:Prevalence
chemical_list: D000900:Anti-Bacterial Agents; D009561:Nisin