Detection of Enterotoxigenic Psychrotrophic Presumptive Bacillus cereus and Cereulide Producers in Food Products and Ingredients

Abstract

In the last decade, foodborne outbreaks and individual cases caused by bacterial toxins showed an increasing trend. The major contributors are enterotoxins and cereulide produced by Bacillus cereus, which can cause a diarrheal and emetic form of the disease, respectively. These diseases usually induce relatively mild symptoms; however, fatal cases have been reported. With the aim to detected potential toxin producers that are able to grow at refrigerator temperatures and subsequently produce cereulide, we screened the prevalence of enterotoxin and cereulide toxin gene carriers and the psychrotrophic capacity of presumptive B. cereus obtained from 250 food products (cereal products, including rice and seeds/pulses, dairy-based products, dried vegetables, mixed food, herbs, and spices). Of tested food products, 226/250 (90.4%) contained presumptive B. cereus, which communities were further tested for the presence of nheA, hblA, cytK-1, and ces genes. Food products were mainly contaminated with the nheA B. cereus carriers (77.9%), followed by hblA (64.8%), ces (23.2%), and cytK-1 (4.4%). Toxigenic B. cereus communities were further subjected to refrigerated (4 and 7 °C) and mild abuse temperatures (10 °C). Overall, 77% (94/121), 86% (104/121), and 100% (121/121) were able to grow at 4, 7, and 10 °C, respectively. Enterotoxin and cereulide potential producers were detected in 81% of psychrotrophic presumptive B. cereus. Toxin encoding genes nheA, hblA, and ces gene were found in 77.2, 55, and 11.7% of tested samples, respectively. None of the psychrotrophic presumptive B. cereus were carriers of the cytotoxin K-1 encoding gene (cytK-1). Nearly half of emetic psychrotrophic B. cereus were able to produce cereulide in optimal conditions. At 4 °C none of the examined psychrotrophs produced cereulide. The results of this research highlight the high prevalence of B. cereus and the omnipresence of toxin gene harboring presumptive B. cereus that can grow at refrigerator temperatures, with a focus on cereulide producers.

Investigation of Virulence and Antibiotic-Resistance of Bacillus cereus Isolated from Various Spices

“…The detection of toxin coding genes among B. cereus isolated showed that more than the half of the samples has either one, two, or three types of nhe . This result is in line with Jovanovic et al who found high number of nhe genes carriers among B. cereus isolates [ 35 ]. The presence of these genes confirm that they are the most prevalent toxin coding genes among B. cereus isolates [ 6 , 33 ].…”

Microbiological quality of hospital‐prepared blenderised tube feeding

“…In the current research, the mean contamination rate of BTF with B. cereus (3.6 ± 0.16 log CFU/m) was significantly higher than the FDA‐recommended limits ( p < 0.05) 12 . In a study conducted by Ankolekar et al, 94 rice samples were evaluated in the United States, and 83 samples (88.3%) were observed to be contaminated with B. cereus , which is consistent with the results of the present study 35 . In another research by Jovanovic et al, the examination of 10 cooked rice samples indicated that 80% of the samples were positive for the presence of diarrhoeal enterotoxin (i.e., non‐hemolytic entrotoxin complex), whereas these genes were not observed in the raw samples of the same product 35 …”

“…12 In a study conducted by Ankolekar et al, 94 rice samples were evaluated in the United States, and 83 samples (88.3%) were observed to be contaminated with B. cereus, which is consistent with the results of the present study. 35 In another research by Jovanovic et al, the examination of 10 cooked rice samples indicated that 80% of the samples were positive for the presence of diarrhoeal enterotoxin (i.e., non-hemolytic entrotoxin complex), whereas these genes were not observed in the raw samples of the same product. 35 In a study by Sharma, a survey of meat products showed that the prevalence of B. cereus contamination was higher in heated meat products than in raw meat.…”

“…35 In another research by Jovanovic et al, the examination of 10 cooked rice samples indicated that 80% of the samples were positive for the presence of diarrhoeal enterotoxin (i.e., non-hemolytic entrotoxin complex), whereas these genes were not observed in the raw samples of the same product. 35 In a study by Sharma, a survey of meat products showed that the prevalence of B. cereus contamination was higher in heated meat products than in raw meat. 36 In this study, the activation of bacterial spores due to heat was one of the factors that increased the contamination of the cooked samples.…”

Functional immune boosters; the herb or its dead microbiome? Antigenic TLR4 agonist MAMPs found in 65 medicinal roots and algae’s

“…Point of sale (POS) products sold as capsules, tablets or powders, therefore, contain not only the plant’s inherent content but also its defunct epiphytic microbiome, comprised of lack of viable pathogens, its dead microbiome and all other residual non-pathogenic live bacteria which remain as aerobic plate counts (APCs), reported as yeasts, molds and fungus in accordance to limits set by local pharmacopeia authorities, the world health organization (WHO) or Food Chemicals Codex monographs. ( Becker et al, 2019 ; Jefri et al, 2022 ; Jovanovic et al, 2022 ; Ma et al, 2022 ; Shi et al, 2021 ; Sholtes et al, 2016 ).…”