Emetic toxin-producing strains of Bacillus cereus show distinct characteristics within the Bacillus cereus group

Abstract

One hundred representative strains of Bacillus cereus were selected from a total collection of 372 B. cereus strains using two typing methods (RAPD and FT-IR) to investigate if emetic toxin-producing hazardous B. cereus strains possess characteristic growth and heat resistance profiles. The strains were classified into three groups: emetic toxin (cereulide)-producing strains (n = 17), strains connected to diarrheal foodborne outbreaks (n = 40) and food-environment strains (n = 43), these latter not producing the emetic toxin. Our study revealed a shift in growth limits towards higher temperatures for the emetic strains, regardless of their origin. None of the emetic toxin-producing strains were able to grow below 10 °C. In contrast, 11% (9 food-environment strains) out of the 83 non-emetic toxin-producing strains were able to grow at 4 °C and 49% at 7 °C (28 diarrheal and 13 food-environment strains). non-emetic toxin-producing strains. All emetic toxin-producing strains were able to grow at 48 °C, but only 39% (16 diarrheal and 16 food-environment strains) of the non-emetic toxinproducing strains grew at this temperature. Spores from the emetic toxin-producing strains showed, on average, a higher heat resistance at 90 °C and a lower germination, particularly at 7 °C, than spores from the other strains. No difference between the three groups in their growth kinetics at 24 °C, 37 °C, and pH 5.0, 7.0, and 8.0 was observed. Our survey shows that emetic toxin-producing strains of B. cereus have distinct characteristics, which could have important implication for the risk assessment of the emetic type of B. cereus caused food poisoning. For instance, emetic strains still represent a special risk in heat-processed foods or preheated foods that are kept warm (in restaurants and cafeterias), but should not pose a risk in refrigerated foods.

Potato Crop as a Source of Emetic Bacillus cereus and Cereulide-Induced Mammalian Cell Toxicity

“…Endophytic cereulide-producing B. cereus organisms from spruce (Picea abies) were also reported to differ in ribopatterns from the nonproducers (NS61 and NS88 [20]). The potato isolates differed from the spruce tree producers in ribopatterns and modest cereulide production, 1 to 100 ng mg of biomass Ϫ1 compared 900 to 1,700 ng mg of biomass Ϫ1 for the NS strains (Norway spruce [51,52,54]). It might be that each plant species carries its own B. cereus cereulide-producing genotype, possibly adapted to the specific metabolic environment inside the host plant.…”

“…Interestingly, a recent epidemiological survey from Finland indicated that the early introduction of root vegetables in infancy was associated with advanced ␤-cell autoimmunity in young children and increased susceptibility to type 1 diabetes (72). Cereulide-producing B. cereus is known to produce spores that are severalfold more resistant to heating at 90°C compared to B. cereus spores of cereulide-nonproducing B. cereus (52). Such spores are likely to survive and become enriched in foods processed by repeated heating.…”

Development of Predictive Growth Models for Staphylococcus aureus and Bacillus cereus on Various Food Matrices Consisting of Ready-to-Eat (RTE) Foods

“…It is a common food contaminant and is an etiological agent of two distinct forms of illness, i.e., emetic and diarrheal. Carlin et al (2006) observed different percentages in spore germination at chilled temperatures among B. cereus genetic groups.…”

Survival of Campylobacter jejuni in mineral bottled water according to difference in mineral content: Application of the Weibull model

“…Parameter p characterises the shape of the curves: concave curves p < 1, convex curves p > 1 and linear curves p equal 1, in this case  parameter can be assimilated to the traditional D value of thermal resistance curves. This equation was used by different authors (Mafart et al, 2002;Virto et al, 2005;Carlin et al, 2006;Buzrul, 2007) and was implemented in this work as primary model. The shape parameter p variation on the goodness of fit of models was shown by Couvert et al (2005) to have slight influence so that a single pvalue can be used for a given microbial population (same physiological state, same preculture) (Couvert et al, 2005).…”