Institut de Recherche pour le Développement, UMR Nutripass, Université Montpellier 1-Université Montpellier 2, Montpellier, France.
J Food Prot. 2012 Sep;75(9):1642-5. doi: 10.4315/0362-028X.JFP-11-450.
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.
本研究旨在评估非洲传统谷物基乳酸发酵糊剂和用于制备婴儿食品的非发酵面粉中蜡样芽孢杆菌群的流行率。发酵糊剂中甘露醇-卵黄-多粘菌素琼脂培养基上的高计数（中位数，4.5×10(4) CFU/ml 糊剂）与非发酵面粉相比，大多数非发酵面粉的计数低于 10(-1) CFU/g。在瓦加杜古（布基纳法索）的 26 种传统谷物基食品中，从 60 株分离株中鉴定了毒力基因。72%和 38%的分离株分别对编码溶血素 BL 和非溶血肠毒素的完整基因集呈阳性，表明这些食源性病原体具有很高的肠毒性潜力。未检测到可能产生呕吐毒素的菌株。由于发酵糊剂中发现的高计数，对接种在发酵糊剂中的营养细胞进行了生存能力测试，结果表明蜡样芽孢杆菌的生长受到抑制。这一结果表明，传统生产单位的发酵可能没有得到充分控制，允许在发酵前的任何单位操作过程中甚至在发酵过程中（当过程控制不佳时）进行生长。然而，添加 0.1 mg/ml 的乳链菌肽可使蜡样芽孢杆菌的数量在 5 小时内减少 5 个对数级，这表明使用乳链菌肽可能是提高这类食品卫生质量的一种方法。
