a b s t r a c t
This study aims at the characterisation of growth behaviour of three strains of Bacillus amyloliquefaciens,
isolated from ropy bread (ATCC8473), wheat grain (ISPA-S109.3) and semolina (ISPA-N9.1) to estimate
rope spoilage risk in pan bread during shelf-life using the Sym'Previus tool. Cardinal values and growth/
no growth boundaries were determined in broth, while artificial spore inoculations were performed in
dough for various pan bread recipes to compare experimental counts with in silico growth simulations.
Finally, two storage scenarios were tested to determine the probability to reach a spoilage threshold
during bread shelf-life. Similarly to the safety criteria fixed for Listeria monocytogenes contamination in
foodstuff complying with EC regulation, a potential rope spoilage threshold was arbitrary fixed at 5 log
CFU/g for B. amyloliquefaciens. This study further underlines a higher rope spoilage potential of the ISPA
strains as compared to the ATCC strain, thus emphasizing the interest to characterise both wild strains
and reference strain to account for biological variability. In conclusion, this study showed that available
decision making tools which are largely recognized to predict behaviour of pathogenic strains, shall also
be used with spoilage strains to help maintain food quality and extend shelf-life.
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