scholarly journals Prediction of growth kinetics of Pseudomonas spp. in meat products under isothermal and non-isothermal storage conditions

2021 ◽  
Vol 7 (3) ◽  
pp. 194-202
Author(s):  
Fatih Tarlak

The main objective of the present study was to develop and validate a new alternative modelling method to predict the shelf-life of food products under non-isothermal storage conditions. The bacterial growth data of the Pseudomonas spp. was extracted from published studies conducted for aerobically-stored fish, pork and chicken meat and described with two-step and one-step modelling approaches employing different primary models (the modified Gompertz, logistic, Baranyi and Huang models) under isothermal storage temperatures. Temperature dependent kinetic parameters (maximum specific growth rate ‘µmax’ and lag phase duration ‘λ’) were described as a function of storage temperature via the Ratkowsky model integrated with each primary model. The Huang model based on the one-step modelling approach yielded the best goodness of fit results (RMSE = 0.451 and adjusted-R2 = 0.942) for all food products at isothermal storage conditions, therefore, was also used to check it’s the prediction capability under non-isothermal storage conditions. The differential form of the Huang model provided satisfactorily statistical indexes (1.075 > Bf > 1.014 and 1.080 > Af > 1.047) indicating reliably being able to use to describe the growth behaviour of Pseudomonas spp. in fish, pork and chicken meat subjected to non-isothermal storage conditions.

2021 ◽  
pp. 108201322110496
Author(s):  
Fatih Tarlak ◽  
Fernando Pérez-Rodríguez

The main objective of the present study was to investigate the effect of storage temperature on aerobically stored chicken meat spoilage using the two-step and one-step modelling approaches involving different primary models namely the modified Gompertz, logistic, Baranyi and Huang models. For this purpose, growth data points of Pseudomonas spp. were collected from published studies conducted in aerobically stored chicken meat product. Temperature-dependent kinetic parameters (maximum specific growth rate ‘µ max’ and lag phase duration ‘ λ’) were described as a function of storage temperature through the Ratkowsky model based on the different primary models. Then, the fitting capability of both modelling approaches was compared taking into account root mean square error, adjusted coefficient of determination (adjusted-R2) and corrected Akaike information criterion. The one-step modelling approach showed considerably improved fitting capability regardless of the used primary model. Finally, models developed from the one-step modelling approach were validated for the maximum growth rate data extracted from independent published literature using the statistical indexes Bias (Bf) and Accuracy (Af) factors. The best prediction capability was obtained for the Baranyi model with Bf and Af being very close to 1. The shelf-life of chicken meat as a function of storage temperature was predicted using both modelling approaches for the Baranyi model.


2017 ◽  
Vol 80 (3) ◽  
pp. 447-453 ◽  
Author(s):  
Ai Kataoka ◽  
Hua Wang ◽  
Philip H. Elliott ◽  
Richard C. Whiting ◽  
Melinda M. Hayman

ABSTRACT The growth characteristics of Listeria monocytogenes inoculated onto frozen foods (corn, green peas, crabmeat, and shrimp) and thawed by being stored at 4, 8, 12, and 20°C were investigated. The growth parameters, lag-phase duration (LPD) and exponential growth rate (EGR), were determined by using a two-phase linear growth model as a primary model and a square root model for EGR and a quadratic model for LPD as secondary models, based on the growth data. The EGR model predictions were compared with growth rates obtained from the USDA Pathogen Modeling Program, calculated with similar pH, salt percentage, and NaNO2 parameters, at all storage temperatures. The results showed that L. monocytogenes grew well in all food types, with the growth rate increasing with storage temperature. Predicted EGRs for all food types demonstrated the significance of storage temperature and similar growth rates among four food types. The predicted EGRs showed slightly slower rate compared with the values from the U.S. Department of Agriculture Pathogen Modeling Program. LPD could not be accurately predicted, possibly because there were not enough sampling points. These data established by using real food samples demonstrated that L. monocytogenes can initiate growth without a prolonged lag phase even at refrigeration temperature (4°C), and the predictive models derived from this study can be useful for developing proper handling guidelines for thawed frozen foods during production and storage.


2020 ◽  
Vol 52 (1) ◽  
pp. 59-63
Author(s):  
S.M. Kuzminskiy ◽  
T.V. Adamchuk ◽  
О.М. Holinko ◽  
N.P. Levytska

Objective of the Work. The overview of current methodical approaches for experimental substantiation of the sell-by date of food products. Methods and Materials. Data analysis of scientific literature and normative documents on methods of substantiation of the sell-by date of food products. Results and Discussion. Sell-by date is a period since product’s manufacture, during which it maintains its safety and quality (including nutritional value) within reasonably foreseeable conditions of storage, distribution and consumption. In the case of new products (recipes) introduction it is necessary to review the sell-by date, and its extending as the need arises. The main aspects of microbiological substantiation of the sell-by date of food products are considered. The identification of microbial hazard for particular product is the first phase of the work. The second phase of the work is to determine the kinetic parameters of precise microorganism’s accumulation to maximum permitted level within regulated and aggravated conditions of product’s storage. Conclusions. In the process of microbiological substantiation of the sell-by date of food products it should be taken into consideration the presence of leading pathogen and causative microorganisms of microbial spoilage, the initial contamination level, the lag phase duration of germ culture development, variations between strains, the kinetics of microorganisms’ accumulation within the product in real and aggravated storage conditions, the indetermination connected with biological nature of microorganisms and their inhomogeneous allocation within the product, the limitation for shortcut research methods (if applicable). The decision rule should be based on the consumer’s risk concept. Key Words: food products, sell-by date, substantiation, microbiological indicators.


2006 ◽  
Vol 69 (6) ◽  
pp. 1312-1321 ◽  
Author(s):  
M. MATARAGAS ◽  
E. H. DROSINOS ◽  
P. SIANA ◽  
P. SKANDAMIS ◽  
I. METAXOPOULOS

To describe the growth limits of Listeria monocytogenes NCTC10527 in a sliced vacuum-packaged cooked cured meat product, the binary logistic regression model was used to develop an equation to determine the probability of growth or no growth of L. monocytogenes as a function of temperature (from 0 to 10°C) and water activity (from 0.88 to 0.98). Two inoculum concentrations were used (10 and 104 CFU g−1), and the growth limits for the two inocula were different. The kinetic behavior of L. monocytogenes as a function of temperature (4, 8, 12, and 16°C) on the same meat product at the lower concentration (10 CFU g−1) was also studied. The Baranyi model appeared to fit the overall experimental data better than did the modified Gompertz and the modified logistic models. Maximum specific growth rate (μmax), lag phase duration (LPD), and maximum cell concentration (Nmax) derived from the primary model were modeled using the square root function (μmax and LPD) and a second order polynomial (Nmax) (secondary models). The selection of the best model (primary or secondary) was based on some statistical indices (the root mean square error of residuals of the model, the regression coefficient, the F test, the goodness of fit, and the bias and accuracy factor). The developed kinetic behavior model was validated under constant and dynamic temperature storage conditions. This prediction of L. monocytogenes growth provides useful information for improving meat safety and can be used for in-depth inspection of quality assurance systems in the meat industry.


2017 ◽  
Vol 80 (11) ◽  
pp. 1872-1876
Author(s):  
Salina Parveen ◽  
Channel White ◽  
Mark L. Tamplin

ABSTRACT During the processing and handling of commercial blue crab (Callinectes sapidus), Listeria monocytogenes can potentially contaminate cooked meat and grow to hazardous levels. To manage this risk, predictive models are useful tools for designing and implementing preventive controls; however, no model specific for blue crab meat has been published or evaluated. In this study, a cocktail of L. monocytogenes strains was added to pasteurized blue crab meat, which was incubated at storage temperatures from 0 to 35°C. At selected time intervals, L. monocytogenes was enumerated by direct plating onto modified Oxford agar. A primary model was fitted to kinetic data to estimate the lag-phase duration (LPD) and growth rate (GR). Listeria monocytogenes replicated from 0 to 35°C, with GR ranging from 0.004 to 0.518 log CFU/h. Overall, the LPD decreased with increasing temperature, displaying a maximum value of 187 h at 0°C; however, this trend was not consistent. The LPD was not detected at 10°C, and it occurred inconsistently from trial to trial. A secondary GR model (R2 = 0.9892) for pasteurized crab meat was compared with the L. monocytogenes GR in fresh crab meat, demonstrating bias and accuracy factors of 0.98 and 1.36, respectively. The model estimates varied from other published data and models, especially at temperatures ≥5°C, supporting the need for a specific predictive tool for temperature deviations.


2019 ◽  
Vol 82 (12) ◽  
pp. 2071-2079 ◽  
Author(s):  
MERLYN THOMAS ◽  
RATNESH TIWARI ◽  
ABHINAV MISHRA

ABSTRACT Listeria monocytogenes is a hardy psychrotrophic pathogen that has been linked to several cheese-related outbreaks in the United States, including a recent outbreak in which a fresh cheese (queso fresco) was implicated. The purpose of this study was to develop primary, secondary, and tertiary predictive models for the growth of L. monocytogenes in queso fresco and to validate these models using nonisothermal time and temperature profiles. A mixture of five strains of L. monocytogenes was used to inoculate pasteurized whole milk to prepare queso fresco. Ten grams of each fresh cheese sample was vacuum packaged and stored at 4, 10, 15, 20, 25, and 30°C. From samples at each storage temperature, subsamples were removed at various times and diluted in 0.1% peptone water, and bacteria were enumerated on Listeria selective agar. Growth data from each temperature were fitted using the Baranyi model as the primary model and the Ratkowsky model as the secondary model. Models were then validated using nonisothermal conditions. The Baranyi model was fitted to the isothermal growth data with acceptable goodness of fit statistics (R2 = 0.928; root mean square error = 0.317). The Ratkowsky square root model was fitted to the specific growth rates at different temperatures (R2 = 0.975). The tertiary model developed from these models was validated using the growth data with two nonisothermal time and temperature profiles (4 to 20°C for 19 days and 15 to 30°C for 11 days). Data for these two profiles were compared with the model prediction using an acceptable prediction zone analysis; >70% of the growth observations were within the acceptable prediction zone (between −1.0 and 0.5 log CFU/g). The model developed in this study will be useful for estimating the growth of L. monocytogenes in queso fresco. These predictions will help in estimation of the risk of listeriosis from queso fresco under extended storage and temperature abuse conditions. HIGHLIGHTS


2012 ◽  
Vol 75 (8) ◽  
pp. 1404-1410 ◽  
Author(s):  
CHENG-AN HWANG ◽  
LIHAN HUANG ◽  
SHIOWSHUH SHEEN ◽  
VIJAY JUNEJA

The surfaces of ready-to-eat meats are susceptible to postprocessing contamination by Listeria monocytogenes. This study examined and modeled the growth characteristics of L. monocytogenes on cooked ham treated with lactic acid solutions (LA). Cooked ham was inoculated with L. monocytogenes (ca. 103 CFU/g), immersed in 0, 0.5, 0.75, 1.0, 1.25, 1.5, and 2.0% LA for 30 min, vacuum packaged, and stored at 4, 8, 12, and 16°C. LA immersion resulted in <0.7 log CFU/g immediate reduction of L. monocytogenes on ham surfaces, indicating the immersion alone was not sufficient for reducing L. monocytogenes. During storage, no growth of L. monocytogenes occurred on ham treated with 1.5% LA at 4 and 8°C and with 2% LA at all storage temperatures. LA treatments extended the lag-phase duration (LPD) of L. monocytogenes and reduced the growth rate (GR) from 0.21 log CFU/day in untreated ham to 0.13 to 0.06 log CFU/day on ham treated with 0.5 to 1.25% LA at 4°C, whereas the GR was reduced from 0.57 log CFU/day to 0.40 to 0.12 log CFU/day at 8°C. A significant extension of the LPD and reduction of the GR of L. monocytogenes occurred on ham treated with >1.25% LA. The LPD and GR as a function of LA concentration and storage temperature can be satisfactorily described by a polynomial or expanded square-root model. Results from this study indicate that immersion treatments with >1.5% LA for 30 min may be used to control the growth of L. monocytogenes on cooked meat, and the models would be useful for selecting LA immersion treatments for meat products to achieve desired product safety.


2017 ◽  
Vol 80 (2) ◽  
pp. 204-212 ◽  
Author(s):  
Karin Söderqvist ◽  
Susanne Thisted Lambertz ◽  
Ivar Vågsholm ◽  
Lise-Lotte Fernström ◽  
Beatrix Alsanius ◽  
...  

ABSTRACT In this study, we investigated the fate of Listeria monocytogenes, pathogenic Yersinia enterocolitica, and Escherichia coli O157:H7 gfp+ inoculated in low numbers into ready-to-eat baby spinach and mixed-ingredient salad (baby spinach with chicken meat). Samples were stored at recommended maximum refrigerator temperature (8°C in Sweden) or at an abuse temperature (15°C) for up to 7 days. Mixed-ingredient salad supported considerable growth when stored at 15°C during shelf life (3 days), with populations of L. monocytogenes, pathogenic Y. enterocolitica, and E. coli O157:H7 gfp+ increasing from less than 2.0 log CFU/g on day 0 to 7.0, 4.0, and 5.6 log CFU/g, respectively. However, when mixed-ingredient salad was stored at 8°C during shelf life, only L. monocytogenes increased significantly, reaching 3.0 log CFU/g within 3 days. In plain baby spinach, only pathogenic Y. enterocolitica populations increased significantly during storage for 7 days, and this was exclusively at an abuse temperature (15°C). Thus, mixing ready-to-eat leafy vegetables with chicken meat strongly influenced levels of inoculated strains during storage. To explore the food safety implications of these findings, bacterial numbers were translated into risks of infection by modeling. The risk of listeriosis (measured as probability of infection) was 16 times higher when consuming a mixed-ingredient salad stored at 8°C at the end of shelf life, or 200,000 times higher when stored at 15°C, compared with when consuming it on the day of inoculation. This indicates that efforts should focus on preventing temperature abuse during storage to mitigate the risk of listeriosis. The storage conditions recommended for mixed-ingredient salads in Sweden (maximum 8°C for 3 days) did not prevent growth of L. monocytogenes in baby spinach mixed with chicken meat. Manufacturers preparing these salads should be aware of this, and recommended storage temperature should be revised downwards to reduce the risk of foodborne disease.


2007 ◽  
Vol 70 (10) ◽  
pp. 2321-2328 ◽  
Author(s):  
CHENG-AN HWANG

Smoked salmon can be contaminated with Listeria monocytogenes. It is important to identify the factors that are capable of controlling the growth of L. monocytogenes in smoked salmon so that control measures can be developed. The objective of this study was to determine the effect of salt, a smoke compound, storage temperature, and their interactions on L. monocytogenes in simulated smoked salmon. A six-strain mixture of L. monocytogenes (102 to 103 CFU/g) was inoculated into minced, cooked salmon containing 0 to 10% NaCl and 0 to 0.4% liquid smoke (0 to 34 ppm of phenol), and the samples were stored at temperatures from 0 to 25°C. Lag-phase duration (LPD; hour), growth rate (GR; log CFU per hour), and maximum population density (MPD; log CFU per gram) of L. monocytogenes in salmon, as affected by the concentrations of salt and phenol, storage temperature, and their interactions, were analyzed. Results showed that L. monocytogenes was able to grow in salmon containing the concentrations of salt and phenol commonly found in smoked salmon at the prevailing storage temperatures. The growth of L. monocytogenes was affected significantly (P < 0.05) by salt, phenol, storage temperature, and their interactions. As expected, higher concentrations of salt or lower storage temperatures extended the LPD and reduced the GR. Higher concentrations of phenol extended the LPD of L. monocytogenes, particularly at lower storage temperatures. However, its effect on reducing the GR of L. monocytogenes was observed only at higher salt concentrations (>6%) at refrigerated and mild abuse temperatures (<10°C). The MPD, which generally reached 7 to 8 log CFU/g in salmon that supported L. monocytogenes growth, was not affected by the salt, phenol, and storage temperature. Two models were developed to describe the LPD and GR of L. monocytogenes in salmon containing 0 to 8% salt, 0 to 34 ppm of phenol, and storage temperatures of 4 to 25°C. The data and models obtained from this study would be useful for estimating the behavior of L. monocytogenes in smoked salmon.


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