Modeling the effect of temperature on growth of Salmonella in chicken

The aim of the study was to determine a growth rate of Salmonella Enteritidis in cooked ham stored under different temperatures and to compare usefulness of the mathematical models for describing the microbiological data. The samples of cooked pork ham were inoculated with the mixture of three Salmonella Enteritidis strains and stored at 5°C, 10°C, 15°C for 21 d, and at 20°C and 25°C for 5 d. The number of salmonellae was determined at 10 periods of storage at each temperature. From each sample a series of decimal dilutions were prepared and plated onto Brilliant Green Agar. The plates were incubated at 37°C for 24-48 h under aerobic conditions. The colonies grown on culture media were counted, bacterial counts were multiplied by the appropriate dilutions, and number of bacteria (colony-forming units) was calculated. The bacterial counts were transformed into logarithms and analysed using IBM SPSS Statistics 20. The experiment was performed in five replicates. The obtained growth curves of bacteria were fitted to primary growth models, namely Gompertz, logistic, and Baranyi models. The goodness-of-fit test was evaluated by calculating mean square error and Akaike's criterion. Growth kinetics values from the modified Gompertz and logistic equations were calculated. It was found that in samples of ham stored at 5°C and 10°C for 21 d, the number of bacteria remained almost at the same level during storage. In samples stored at 15°C, 20°C, and 25°C growth of salmonellae was observed. It was found that logistic model gave in most cases the best fit to obtained microbiological data describing the behaviour of S. Enteritidis in cooked ham. The growth kinetics values calculated in this study from logistic equations can be used to predict potential S. Enteritidis growth in cooked ham stored at 15°C, 20°C, and 25°C.

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“…1) and logistic model (Eq. 2) are the most frequently used to describe the bacterial growth in foods (4,10,13,14).…”

Section: Methodsmentioning

confidence: 99%

Effect of temperature on the growth kinetics of Salmonella Enteritidis in cooked ham

Szczawinska

Szczawinski

Łobacz

2014

Bulletin of the Veterinary Institute in Pulawy

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“…The modified Gompertz primary model for microbial growth could be expressed by the following equation [8]:…”

Section: The Primary Model and Mathematical Modelling Under Dynamicalmentioning

confidence: 99%

Microbial growth modelling under variable temperature conditions

Popov¹,

Gospavić²,

Kreyenschmidt³

et al. 2009

Environmental Health Risk V

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The application of a Quantitative Microbial Risk Assessment (QMRA) in food supply chains requires accurate prediction of microbial growth under variable temperature conditions. A dynamical growth model under variable temperature conditions was developed using raw data for microbial growth of Pseudomonas spp. in poultry under aerobic conditions from a food supply chain in Germany. The primary model was developed using measurement data under a set of fixed temperatures and constant environmental conditions. The two primary models used for modelling the growth under constant temperature conditions were: Baranyi and modified Gompertz. As a secondary model the square root model was used for maximal growth rate in the Baranyi model and polynomial interpolation for the modified Gompertz model. In the case of the Baranyi model the main assumption, that the initial physiological state of the inoculum is constant and independent of the environmental parameters, is used. The generated dynamical models are validated by comparing the predictions obtained by both models with data measured under dynamical temperature conditions. Two temperature profiles were used for comparison and good agreement has been found between experimental data and model predictions.

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“…Especially, raw poultry products are perceived to be related with a significant amount of food poisoning due to the frequent cases of poultry contaminated with pathogens (Kessel et al, 2001;Zhao et al, 2001). Also, it was reported that these sorts of disease can be caused by temperature abuse during storage and distribution (Juneja et al, 2007). For this reason, the cold chain system is recommended as the most effective way to ensure freshness and safety of food products.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Properties and Freshness of Spent Hen's Meat under Frozen or Refrigeration Conditions after Thawing

Gu¹,

Gu²,

Park³

et al. 2012

Korean Journal for Food Science of Animal Resources

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This study was conducted in order to investigate the effect of storage temperature abuse on the freshness of refrigerated and frozen spent hen's meat. After a room temperature storage condition, two different storage temperature were followed: refrigeration and frozen storage. All parts of the spent hen's meats were thawed at 4 d intervals up to 3 times (2, 6, and 10 d) for 24 h. The level of bacteria on the different parts of the refrigerated and frozen meats was higher than 6 Log CFU/g under the following storage conditions: refrigerated -breast, 12 h; leg, 6 h; wing, 12 h at the 1 st analysis, frozen -breast, 12 h at the 2 nd analysis; leg, 24 h at the 1 st analysis; wing, 12 h at the 1 st analysis. The pH value for the leg meat was higher than breast and wing meats. In the color measurements, under the room temperature storage condition, lightness and redness values decreased but the yellowness increased in refrigerated meats (p<0.05). The K-value regarding refrigerated leg meats exceeded 60%, which is the threshold value to evaluate the degree of freshness, during the 1 st analysis (p<0.05). The VBN value of refrigerated leg meat was the highest and reached up to 96.93 mg%. Thus, studies regarding the possible decline in quality according to the change of storage temperature could be used in order to establish a basic database for the quality control of spent hen meat being traded with other countries.

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Modeling the effect of temperature on growth of Salmonella in chicken

Cited by 128 publications

References 13 publications

Effect of temperature on the growth kinetics of Salmonella Enteritidis in cooked ham

Effect of temperature on the growth kinetics of Salmonella Enteritidis in cooked ham

Microbial growth modelling under variable temperature conditions

Physicochemical Properties and Freshness of Spent Hen's Meat under Frozen or Refrigeration Conditions after Thawing

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