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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

Mean Probability of illness by consumption of PIF contaminated with an initial inoculum of 1 cell (A) and 50 (B) cells and growth at four different temperatures. Each temperature has three probability of illness according to cells treated with 50°C by 0 (P ill 1), 5 min (P ill 2), and 10 min (P ill 3) and so on, respectively. The concentration to estimate the probabilities were taken from stochastic growth model using the cut-off point when the deterministic growth model reached 1000 CFU/ml (See Figure 3).
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Figure 5: Mean Probability of illness by consumption of PIF contaminated with an initial inoculum of 1 cell (A) and 50 (B) cells and growth at four different temperatures. Each temperature has three probability of illness according to cells treated with 50°C by 0 (P ill 1), 5 min (P ill 2), and 10 min (P ill 3) and so on, respectively. The concentration to estimate the probabilities were taken from stochastic growth model using the cut-off point when the deterministic growth model reached 1000 CFU/ml (See Figure 3).

Mentions: Figure 5 shows the mean probability of illness by consumption of PIF contaminated with an initial inoculum of 1 (Figure 5A) and 50 (Figure 5B) cells growing at four different temperatures with the input of the stochastic growth model at the concentrations when the deterministic model reached 1000 CF/ml (Figure 3). It can be observed that the effect of the temperature and the inoculum size in the probability of illness. As expected the higher inoculum size and growth temperature were, the higher the mean probability of illness. The probability of illness from initial inoculum size of 1 cell were below 0.2 in all the cases and for inoculum size of 50 cells the probability of illness were, in most of the cases, above 0.7; the probability of illness was 0.68 and 0.69 by consumption of PIF with cell survivor to 50°C by 5 and 10 min, respectively (Figure 5B).


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)

Mean Probability of illness by consumption of PIF contaminated with an initial inoculum of 1 cell (A) and 50 (B) cells and growth at four different temperatures. Each temperature has three probability of illness according to cells treated with 50°C by 0 (P ill 1), 5 min (P ill 2), and 10 min (P ill 3) and so on, respectively. The concentration to estimate the probabilities were taken from stochastic growth model using the cut-off point when the deterministic growth model reached 1000 CFU/ml (See Figure 3).
© Copyright Policy
Related In: Results  -  Collection

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

Figure 5: Mean Probability of illness by consumption of PIF contaminated with an initial inoculum of 1 cell (A) and 50 (B) cells and growth at four different temperatures. Each temperature has three probability of illness according to cells treated with 50°C by 0 (P ill 1), 5 min (P ill 2), and 10 min (P ill 3) and so on, respectively. The concentration to estimate the probabilities were taken from stochastic growth model using the cut-off point when the deterministic growth model reached 1000 CFU/ml (See Figure 3).
Mentions: Figure 5 shows the mean probability of illness by consumption of PIF contaminated with an initial inoculum of 1 (Figure 5A) and 50 (Figure 5B) cells growing at four different temperatures with the input of the stochastic growth model at the concentrations when the deterministic model reached 1000 CF/ml (Figure 3). It can be observed that the effect of the temperature and the inoculum size in the probability of illness. As expected the higher inoculum size and growth temperature were, the higher the mean probability of illness. The probability of illness from initial inoculum size of 1 cell were below 0.2 in all the cases and for inoculum size of 50 cells the probability of illness were, in most of the cases, above 0.7; the probability of illness was 0.68 and 0.69 by consumption of PIF with cell survivor to 50°C by 5 and 10 min, respectively (Figure 5B).

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