Influence of type of food on the kinetics and overall production of Bacillus cereus emetic toxin.
Potato puree and penne pasta were inoculated with cereulide producing B. cereus 5964a and B. cereus NS117. Static incubation at 28 degrees C proved these two foods to be a better substrate for higher cereulide production (4,080 ng/g in puree and 3,200 ng/g in penne were produced by B. cereus 5964a during 48 h of incubation) compared with boiled rice (2,000 ng/g). This difference occurred despite B. cereus counts of more than 10(8) CFU/g in all three products. Aeration of cultures had a negative effect on cereulide production, causing concentrations more than 10-fold lower than in some statically incubated samples. Cereulide production remained undetectable in shaken milk, whereas it reached 1,140 ng/ml in statically incubated milk. At 12 and 22 degrees C, presence of background flora was also a determinative factor. A total B. cereus count of more than 106 CFU/ml did not necessarily lead to uniform cereulide production and was also dependent on the B. cereus strain involved. In this study, we confirm that a number of factors play a crucial role in the determination of the extent to which, if at all, cereulide will be produced. Among those, type of the food, temperature, pH, and whether additional aeration (via incubation on an orbital shaker) is induced had an important role. An important effect was also induced by the cereulide-producing strain involved.
Rajkovic
Andreja
A
Laboratory for Food Microbiology and Food Preservation, Department for Food Safety and Food Quality, Faculty of Bioengineering Sciences, Ghent University, Belgium.
Uyttendaele
Mieke
M
Ombregt
Sylvie-Anne
SA
Jaaskelainen
Elina
E
Salkinoja-Salonen
Mirja
M
Debevere
Johan
J
D001409:Bacillus cereus / Q000254:growth & development* / Q000378:metabolism*; D015169:Colony Count, Microbial; D047630:Depsipeptides / Q000096:biosynthesis; D004768:Enterotoxins / Q000096:biosynthesis*; D005516:Food Microbiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013696:Temperature; D013997:Time Factors
D047630:Depsipeptides; D004768:Enterotoxins; C089294:cereulide; C040792:enterotoxin, Bacillus cereus