Effect of environmental parameters on growth kinetics of Bacillus cereus (ATCC 7004) after mild heat treatment.
The influence of temperature (10 to 50 degrees C), initial pH (4.0 to 6.0) and sodium chloride concentration (0.5 to 3.0%) on the growth in nutrient broth and in meat extract of Bacillus cereus after mild heat treatment (90 degrees C--10 min) was determined. B. cereus spores survived after heating and they were able to germinate and grow in both media when post-treatment conditions were favourable. Heated B. cereus did not grow at 10 and 50 degrees C or in a medium with pH 4.0. Decreasing pH values and increasing levels of sodium chloride decreased growth rate and increased the lag phase of B. cereus. pH 4.5 was unable to prevent the growth of heated spores in a meat substrate with 0.5% NaCl at 12 degrees C. The combination of pH </=4.5, NaCl concentration >/=1.0% and temperatures </=12 degrees C was sufficient to inhibit B. cereus growth after heat treatment at 90 degrees C for 10 min, for at least 50 days in nutrient broth and in meat extract. Re-heating at temperatures >/=60 degrees C could control heated B. cereus ATCC 7004 growth.
Martínez
Sidonia
S
Area de Tecnología de los Alimentos, Facultad de Ciencias de Ourense, Universidad de Vigo, Campus Universitario, s/n. 32004 Ourense, Spain. sidonia@uvigo.es
Borrajo
Rubén
R
Franco
Inmaculada
I
Carballo
Javier
J
D001409:Bacillus cereus / Q000187:drug effects / Q000254:growth & development*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D005506:Food Contamination / Q000517:prevention & control; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological; D012965:Sodium Chloride / Q000494:pharmacology*; D013696:Temperature
D012965:Sodium Chloride