title: Sporulation environment of emetic toxin-producing Bacillus cereus strains determines spore size, heat resistance and germination capacity.
abstract: OBJECTIVE
  Heat resistance, germination and outgrowth capacity of Bacillus cereus spores in processed foods are major factors in causing the emetic type of gastrointestinal disease. In this study, we aim to identify the impact of different sporulation conditions on spore properties of emetic toxin-producing B. cereus strains.
  
  
  RESULTS
  Spore properties of eight different emetic toxin-producing strains were tested, with spores produced in five different sporulation conditions: aerated liquid cultures, air-liquid biofilms, 1.5% agar plates, 0.75% agar plates and swarming colonies. Model food studies revealed spores from emetic toxin-producing strains to germinate efficiently on meat broth- and milk-based agar plates, whereas germination on rice-based agar plates was far less efficient. Notably, spores of all strains germinated efficiently when 0.1% meat broth was added to the rice plates. Analysis of spores derived from different environments revealed large diversity and showed biofilm spores for the strains tested to be the largest in size, the most heat resistant and with the lowest germination capacity.
  
  
  CONCLUSIONS
  Sporulation in complex conditions such as biofilms and surface swarming colonies increases heat resistance and dormancy of spores.
  
  
  CONCLUSIONS
  The results obtained imply the importance of sporulation conditions on spore properties of emetic toxin-producing B. cereus strains, as occur for instance in food processing.
authors.affiliation: Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: van der Voort
authors.forename: T
authors.initials: T
authors.lastname: Abee
mesh_terms: D001409:Bacillus cereus / Q000502:physiology*; D001427:Bacterial Toxins / Q000096:biosynthesis; D001431:Bacteriological Techniques; D005506:Food Contamination; D005516:Food Microbiology; D006358:Hot Temperature; D010848:Picolinic Acids / Q000032:analysis; D013171:Spores, Bacterial
chemical_list: D001427:Bacterial Toxins; D010848:Picolinic Acids; C004860:dipicolinic acid