Influence of Cooling Rate on Growth of Bacillus cereus from Spore Inocula in Cooked Rice, Beans, Pasta, and Combination Products Containing Meat or Poultry

• Published in: Journal of food protection 2018-03, Vol.81 (3), p.430-436
• Main Authors: Juneja, Vijay K, Mohr, Tim B, Silverman, Meryl, Snyder, O Peter
• Format: Article
• Language: English
• Subjects: Agar; Agriculture; Bacillus cereus; Beans; Beef; Chickens; Clostridium botulinum; Clostridium perfringens; Cooking; Cooling; Cooling rate; Enzymes; Food contamination & poisoning; Food safety; Food service; Hazards; Heat; Heat resistance; Illnesses; Mannitol; Meat; Pasta; Pathogens; Poultry; Public health; Rice; Spores; Temperature; Vegetables; Yolk
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X.JFP-17-397

The objective of this study was to assess the ability of Bacillus cereus spores to germinate and grow in order to determine a safe cooling rate for cooked rice, beans, and pasta, rice-chicken (4:1), rice-chicken-vegetables (3:1:1), rice-beef (4:1), and rice-beef-vegetables (3:1:1). Samples were inoculated with a cocktail of four strains of heat-shocked (80°C for 10 min) B. cereus spores (NCTC 11143, 935A/74, Brad 1, and Mac 1) to obtain a final spore concentration of approximately 2 log CFU/g. Thereafter, samples were exponentially cooled through the temperature range of 54.5 to 7.2°C in 6, 9, 12, 15, 18, and 21 h. At the end of the cooling period, samples were removed and plated on mannitol egg yolk polymyxin agar. The plates were incubated at 30°C for 24 h. The net B. cereus growth from spores in beans was