Effect of heat shock and recovery temperature on variability of single cell lag time of Cronobacter turicensis.
Food Microbiol
; 45(Pt B): 195-204, 2015 Feb.
Article
en En
| MEDLINE
| ID: mdl-25500385
The effect of heat stress and subsequent recovery temperature on the individual cellular lag of Cronobacter turicensis was analysed using optical density measurements. Low numbers of cells were obtained through serial dilution and the time to reach an optical density of 0.035 was determined. Assuming the lag of a single cell follows a shifted Gamma distribution with a fixed shape parameter, the effect of recovery temperature on the individual lag of untreated and sublethally heat treated cells of Cr. turicensis were modelled. It was found that the shift parameter (Tshift) increased asymptotically as the temperature decreased while the logarithm of the scale parameter (θ) decreased linearly with recovery temperature. To test the validity of the model in food, growth of low numbers of untreated and heat treated Cr. turicensis in artificially contaminated infant first milk was measured experimentally and compared with predictions obtained by Monte Carlo simulations. Although the model for untreated cells slightly underestimated the actual growth in first milk at low temperatures, the model for heat treated cells was in agreement with the data derived from the challenge tests and provides a basis for reliable quantitative microbiological risk assessments for Cronobacter spp. in infant milk.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Contaminación de Alimentos
/
Fórmulas Infantiles
/
Cronobacter
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Food Microbiol
Asunto de la revista:
CIENCIAS DA NUTRICAO
/
MICROBIOLOGIA
Año:
2015
Tipo del documento:
Article
País de afiliación:
Reino Unido
Pais de publicación:
Reino Unido