title: Survival of Bacillus cereus vegetative cells and spores during in vitro simulation of gastric passage.
abstract: The enteric pathogen Bacillus cereus must survive gastric passage in order to cause diarrhea by enterotoxin production in the small intestine. The acid resistance and the survival after gastric passage were assessed by in vitro experiments with acidified growth medium and gastric  simulation medium with B. cereus NVH 1230-88 vegetative cells and spores. First, batch incubations at constant pH values for 4 h, which represented different physiological states of the stomach, showed that spores were resistant to any gastric condition in the pH range of 2.0 to 5.0,  while vegetative cells were rapidly inactivated at pH values of ≤4.0. Second, a dynamic in vitro gastric experiment was conducted that simulated the continuously changing in vivo conditions due to digestion dynamics by gradually decreasing the pH from 5.0 to 2.0 and fractional emptying  of the stomach 30 to 180 min from the start of the experiment. All of the B. cereus spores and 14% (± 9%) of the vegetative cells survived the dynamic simulation of gastric passage.
authors.affiliation: Faculty of Bioscience Engineering, Department of Food Safety and Quality, Laboratory of Food Microbiology and Food Preservation (LFMFP), Ghent University, Ghent, Belgium.
authors.forename: Siele
authors.initials: S
authors.lastname: Ceuppens
authors.forename: Mieke
authors.initials: M
authors.lastname: Uyttendaele
authors.forename: Katrien
authors.initials: K
authors.lastname: Drieskens
authors.forename: Andreja
authors.initials: A
authors.lastname: Rajkovic
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Tom Van de
authors.initials: TV
authors.lastname: Wiele
mesh_terms: D001409:Bacillus cereus / Q000502:physiology*; D005744:Gastric Acid; D005772:Gastrointestinal Transit; D006801:Humans; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability; D008954:Models, Biological; D013171:Spores, Bacterial; D013270:Stomach / Q000382:microbiology