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Variability in Cell Response of Cronobacter sakazakii after Mild-Heat Treatments and Its Impact on Food Safety.

Parra-Flores J, Juneja V, Garcia de Fernando G, Aguirre J - Front Microbiol (2016)

Bottom Line: Stochastic approaches can better describe microbial single cell response than deterministic models as we prove in this study.This variability increased as the heat shock increased and growth temperature decreased.The mean probability of illness from initial inoculum size of 1 cell was below 0.2 in all the cases and for inoculum size of 50 cells the mean probability of illness, in most of the cases, was above 0.7.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Nutrición y Salud Pública, Universidad del Bío-Bío Chillán, Chile.

ABSTRACT
Cronobacter spp. have been responsible for severe infections in infants associated with consumption of powdered infant formula and follow-up formulae. Despite several risk assessments described in published studies, few approaches have considered the tremendous variability in cell response that small micropopulations or single cells can have in infant formula during storage, preparation or post process/preparation before the feeding of infants. Stochastic approaches can better describe microbial single cell response than deterministic models as we prove in this study. A large variability of lag phase was observed in single cell and micropopulations of ≤50 cells. This variability increased as the heat shock increased and growth temperature decreased. Obviously, variability of growth of individual Cronobacter sakazakii cell is affected by inoculum size, growth temperature and the probability of cells able to grow at the conditions imposed by the experimental conditions should be taken into account, especially when errors in bottle-preparation practices, such as improper holding temperatures, or manipulation, may lead to growth of the pathogen to a critical cell level. The mean probability of illness from initial inoculum size of 1 cell was below 0.2 in all the cases and for inoculum size of 50 cells the mean probability of illness, in most of the cases, was above 0.7.

No MeSH data available.


Related in: MedlinePlus

Probability of growth (Pg) of C. sakazakii as a function of exposure time at 50°C by 0, 5, and 10 min and growth temperatures of 5, 10, 15, and 25°C. The continuous black lines, for which equations are shown in the figure, show the relationships found in our experiments.
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Figure 2: Probability of growth (Pg) of C. sakazakii as a function of exposure time at 50°C by 0, 5, and 10 min and growth temperatures of 5, 10, 15, and 25°C. The continuous black lines, for which equations are shown in the figure, show the relationships found in our experiments.

Mentions: Figure 2 shows the mean probability of cell able to growth (Pg) as a function of the time of heat treatment and temperature. It was observed that as the heat treatment increased, Pg decreased; in addition, the higher the temperature, the higher was the Pg, indicating a significant variation in the number cells with growth ability. For example, at 25°C, the Pg was 0.05 for cells that survived heating at 50°C for 10 min, whereas the Pg was 0.97 for cells treated for 10 min at 50°C.


Variability in Cell Response of Cronobacter sakazakii after Mild-Heat Treatments and Its Impact on Food Safety.

Parra-Flores J, Juneja V, Garcia de Fernando G, Aguirre J - Front Microbiol (2016)

Probability of growth (Pg) of C. sakazakii as a function of exposure time at 50°C by 0, 5, and 10 min and growth temperatures of 5, 10, 15, and 25°C. The continuous black lines, for which equations are shown in the figure, show the relationships found in our experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4836016&req=5

Figure 2: Probability of growth (Pg) of C. sakazakii as a function of exposure time at 50°C by 0, 5, and 10 min and growth temperatures of 5, 10, 15, and 25°C. The continuous black lines, for which equations are shown in the figure, show the relationships found in our experiments.
Mentions: Figure 2 shows the mean probability of cell able to growth (Pg) as a function of the time of heat treatment and temperature. It was observed that as the heat treatment increased, Pg decreased; in addition, the higher the temperature, the higher was the Pg, indicating a significant variation in the number cells with growth ability. For example, at 25°C, the Pg was 0.05 for cells that survived heating at 50°C for 10 min, whereas the Pg was 0.97 for cells treated for 10 min at 50°C.

Bottom Line: Stochastic approaches can better describe microbial single cell response than deterministic models as we prove in this study.This variability increased as the heat shock increased and growth temperature decreased.The mean probability of illness from initial inoculum size of 1 cell was below 0.2 in all the cases and for inoculum size of 50 cells the mean probability of illness, in most of the cases, was above 0.7.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Nutrición y Salud Pública, Universidad del Bío-Bío Chillán, Chile.

ABSTRACT
Cronobacter spp. have been responsible for severe infections in infants associated with consumption of powdered infant formula and follow-up formulae. Despite several risk assessments described in published studies, few approaches have considered the tremendous variability in cell response that small micropopulations or single cells can have in infant formula during storage, preparation or post process/preparation before the feeding of infants. Stochastic approaches can better describe microbial single cell response than deterministic models as we prove in this study. A large variability of lag phase was observed in single cell and micropopulations of ≤50 cells. This variability increased as the heat shock increased and growth temperature decreased. Obviously, variability of growth of individual Cronobacter sakazakii cell is affected by inoculum size, growth temperature and the probability of cells able to grow at the conditions imposed by the experimental conditions should be taken into account, especially when errors in bottle-preparation practices, such as improper holding temperatures, or manipulation, may lead to growth of the pathogen to a critical cell level. The mean probability of illness from initial inoculum size of 1 cell was below 0.2 in all the cases and for inoculum size of 50 cells the mean probability of illness, in most of the cases, was above 0.7.

No MeSH data available.


Related in: MedlinePlus