Occurrence, growth, and virulence genes of <i>Bacillus cereus</i> in ready-to-cook plant-based meat analogues

Dušková, Marta; Kameník, Josef; Čutová, Michaela; Dorotíková, Kateřina; Králová, Michaela; Šedo, Ondrej

doi:10.2754/avb202594040317

Acta Veterinaria > Archive > 2025, Vol. 94 > Issue 4 > Occurrence, growth, and virulence genes…

Acta Vet. Brno 2025, 94: 317-327

https://doi.org/10.2754/avb202594040317

Occurrence, growth, and virulence genes of Bacillus cereus in ready-to-cook plant-based meat analogues

Marta Dušková¹, Josef Kameník¹, Michaela Čutová¹, Kateřina Dorotíková¹, Michaela Králová¹, Ondrej Šedo²

¹University of Veterinary Sciences Brno, Faculty of Veterinary Hygiene and Ecology, Department of Animal Origin Food and Gastronomic Sciences, Brno, Czech Republic
²Central European Institute of Technology, Masaryk University, Brno, Czech Republic

Received October 3, 2025
Accepted October 20, 2025

The aim of this study was to monitor the growth of Bacillus cereus in 11 different types of naturally contaminated ready-to-cook plant-based meat analogues (PBMAs). The PBMAs were prepared according to the manufacturer’s instructions and subsequently stored at room temperature for up to 24 h. Bacillus spp. represented the second most numerous group of microbiota detected in PBMAs after lactic acid bacteria. Bacillus cereus sensu lato (s.l.) was isolated from all 11 PBMA samples. Following heat treatment and 24-h storage at 22 °C, B. cereus s.l. was detected by plate counting in five samples, with one product reaching nearly 4 log CFU/g. The presence of B. cereus sensu stricto (s.s.) was detected in all 11 samples. Bacillus thuringiensis was present in 7 samples, and in 4 PBMA samples the species B. weihenstephanensis, B. mycoides, and B. cytotoxicus were found. A total of 95.7% of B. cereus s.l. strains contained genes for toxin production. The presence of nhe genes was demonstrated in 92.5%, hbl genes in 59.0% of the analysed B. cereus s.l. strains, the cytK-1 gene in 5 strains (B. cytotoxicus). The presence of the ces gene was confirmed in 5% of B. cereus s.l. strains. In total, 47 different combinations of genes for toxin production were detected in B. cereus s.l. strains. The almost 100% presence of virulence genes associated with the possibility of B. cereus growth during inappropriate storage of PBMAs thus poses a risk for the development of foodborne diseases.

Keywords

Total viable count, heat treatment, hbl genes, nhe genes, ces gene, Bacillus cytotoxicus.

Funding

This research was supported by the project of the University of Veterinary Sciences Brno 2023ITA24. We acknowledge CEITEC Proteomics Core Facility of CIISB, Instruct-CZ Centre, supported by MEYS CR (LM2023042, CZ.02.01.01/00/23_015/0008175).