Influence of the sporulation temperature on the impact of the nutrients inosine and l-alanine on Bacillus cereus spore germination.
The effect of sporulation temperature on Bacillus cereus spore germination triggered by the nutrient germinants inosine and l-alanine was investigated. The germination (expressed as % A(600nm) fall) of heat-activated spores of B. cereus strain ATCC14579 produced at 20 and 37 degrees C, and of psychrotrophic strains LM9 and D15 produced at 15 and 37 degrees C was followed in a germination buffer containing inosine at concentrations between 0.01 and 10mmoll(-1), or l-alanine between 1 and 100mmoll(-1). Spores wet-heat resistance at 90 degrees C was also determined. Spores of the three strains produced at the lowest temperatures generally showed a higher germination capacity in response to both inosine and in l-alanine than those produced at 37 degrees C, and were also more susceptible to heat. Low sporulation temperature is confirmed as a detrimental factor to B. cereus spore wet-heat resistance, and conversely gave spores with a sensitivity to the nutrient germinants inosine and l-alanine higher than that of spores formed close to the maximal sporulation temperature.
Gounina-Allouane
Rabia
R
UMR 408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Université d'Avignon, Site Agroparc, F-84000 Avignon, Cedex, France.
Broussolle
Véronique
V
Carlin
Frédéric
F
D000409:Alanine / Q000494:pharmacology*; D001409:Bacillus cereus / Q000502:physiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D005516:Food Microbiology; D007288:Inosine / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects* / Q000254:growth & development; D013696:Temperature; D013997:Time Factors
D007288:Inosine; D000409:Alanine