This study investigated B. cereus levels in fried rice meals in Milan (Italy) and the effect of a post contamination. Spores of three B. cereus (ATCC 14579, clinical isolate GPe2 and an isolate from fried rice R1) were inoculated in fried rice with ham, scrambled egg and peas, then stored at 10 °C and 15 °C for 5 days; the L2 component of haemolysin BL was quantified in the product. In a second trial, inoculated fried rice was submitted to microwave heating (2 min at 600 W) to investigate a possible decrease in bacterial loads. At 15 °C, spores germinated very quickly, followed by a fast growth especially of B. cereus R1 (+5.92 Log CFU g⁻¹ from T0), statistically higher if compared to ATCC 14579 and GPe2 strains at 15 °C (P < 0.05 and P < 0.01). The production of HBL toxin by the R1 strain significantly started after 2 days in samples at 15 °C, while the production by ATCC and GPe2 strains was more modest and late. At 10 °C, R1 showed a significant fast growth (+4.64 Log CFU g⁻¹ from T0) and significant HBL toxin production (from T4), if compared to GPe2 and ATCC strains that showed absent or very slow growth (P < 0.05).

这项研究调查了米兰（意大利）炒米粉中蜡状芽孢杆菌的含量以及污染后的影响。将三种蜡状芽孢杆菌（ATCC 14579，临床分离株GPe2和来自炒饭R1的分离株）的孢子接种到炒饭中，加入火腿，炒鸡蛋和豌豆，然后分别在10°C和15°C下保存5天；在产品中定量溶血素BL的L2成分。在第二项试验中，将接种的炒饭置于微波加热（600 W下2分钟）中，以研究细菌负荷的可能降低。在15°C时，孢子发芽非常快，随后快速增长，尤其是蜡状芽孢杆菌R1（+5.92 Log CFU g ^-1与ATCC 14579和GPe2菌株在15°C时相比，具有更高的统计学意义（P <0.05和P <0.01）。在15°C下两天后，由R1菌株产生的HBL毒素显着开始，而由ATCC和GPe2菌株产生的HBL毒素则更为缓慢。在10°C下，与GPe2和ATCC菌株缺乏或非常缓慢生长的GPe2和ATCC菌株相比，R1显示出显着的快速生长（T0 +4.64 Log CFU g ^-1来自T0）和显着的HBL毒素产生（来自T4）（P <0.05 ）。