Table_4_Effect of Calcium and Manganese Supplementation on Heat Resistance of Spores of Bacillus Species Associated With Food Poisoning, Spoilage, and Fermentation.DOCX

Bacterial spores often survive thermal processing used in the food industry, while heat treatment leads not only to a decrease in the nutritional and organoleptic properties of foods, but also to a delay in fermentation of fermented foods. Selective reduction of undesirable spores without such impediments is an ongoing challenge for food scientists. Thus, increased knowledge of the spore-forming bacteria is required to control them. In this study, the heat resistance results (D100°C) of the spores of four Bacillus species were determined and compared to previous literature, and found that B. cereus has significantly lower heat resistance than the other Bacillus species, B. coagulans, B. subtilis, and B. licheniformis. Using the spores of these strains, this study also evaluated the effects of single and combined supplementation of calcium (0.00–2.00 mM) and manganese (0.00–0.50 mM) on heat resistance (D100°C). The results revealed that the spores of B. licheniformis and B. cereus displayed the smallest heat resistance when sporulated on media rich in calcium. Conversely, B. coagulans spores and B. subtilis spores exhibited the greatest heat resistance when sporulated under calcium-rich conditions. The opposite results (stronger heat resistance for B. licheniformis spores and B. cereus spores, and smaller heat resistance for B. coagulans spores and B. subtilis spores) were obtained when the spores were formed on media poor in the minerals (particularly calcium). Based on the results, the Bacillus species were divided into two groups: B. licheniformis and B. cereus; and B. coagulans and B. subtilis. The study provides valuable insight to selectively reduce spores of undesirable Bacillus species in the food industry.

细菌芽孢往往能够在食品工业常用的热处理过程中存活，而热处理不仅会降低食品的营养与感官品质，还会延缓发酵食品的发酵进程。在不产生上述不良影响的前提下选择性去除有害芽孢，仍是食品科学家面临的长期挑战。因此，学界需要加深对产芽孢细菌的认知，以实现对其的有效防控。本研究测定了4种芽孢杆菌属细菌芽孢的热抗性（D100°C）结果，并与既往文献数据进行对比，发现蜡样芽孢杆菌（B. cereus）的热抗性显著低于其他3种芽孢杆菌，即凝结芽孢杆菌（B. coagulans）、枯草芽孢杆菌（B. subtilis）与地衣芽孢杆菌（B. licheniformis）。本研究还利用上述菌株的芽孢，评估了单独及联合添加钙（0.00–2.00 mM）与锰（0.00–0.50 mM）对芽孢热抗性（D100°C）的影响。结果显示，当在富钙培养基中形成芽孢时，地衣芽孢杆菌与蜡样芽孢杆菌的芽孢热抗性最低。与之相反，凝结芽孢杆菌与枯草芽孢杆菌的芽孢在富钙条件下形成芽孢时，热抗性最高。而当芽孢在矿物质（尤其是钙）匮乏的培养基中形成时，则得到了相反的结果：地衣芽孢杆菌与蜡样芽孢杆菌的芽孢热抗性更强，凝结芽孢杆菌与枯草芽孢杆菌的芽孢热抗性更低。基于上述结果，本研究将受试芽孢杆菌划分为两组：一组为地衣芽孢杆菌与蜡样芽孢杆菌，另一组为凝结芽孢杆菌与枯草芽孢杆菌。本研究为食品工业中选择性去除有害芽孢杆菌属细菌的芽孢提供了极具价值的理论参考。