Development of a Microbial Model for the Combined Effect of Temperature and pH on Spoilage of Ground Meat, and Validation of the Model under Dynamic Temperature Conditions
Open Access
- 1 January 2006
- journal article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 72 (1), 124-134
- https://doi.org/10.1128/aem.72.1.124-134.2006
Abstract
The changes in microbial flora and sensory characteristics of fresh ground meat (beef and pork) with pH values ranging from 5.34 to 6.13 were monitored at different isothermal storage temperatures (0 to 20°C) under aerobic conditions. At all conditions tested, pseudomonads were the predominant bacteria, followed by Brochothrix thermosphacta, while the other members of the microbial association (e.g., lactic acid bacteria and Enterobacteriaceae) remained at lower levels. The results from microbiological and sensory analysis showed that changes in pseudomonad populations followed closely sensory changes during storage and could be used as a good index for spoilage of aerobically stored ground meat. The kinetic parameters (maximum specific growth rate [μmax] and the duration of lag phase [λ]) of the spoilage bacteria were modeled by using a modified Arrhenius equation for the combined effect of temperature and pH. Meat pH affected growth of all spoilage bacteria except that of lactic acid bacteria. The “adaptation work,” characterized by the product of μmax and λ(μmax × λ) was found to be unaffected by temperature for all tested bacteria but was affected by pH for pseudomonads and B. thermosphacta. For the latter bacteria, a negative linear correlation between ln(μmax × λ) and meat pH was observed. The developed models were further validated under dynamic temperature conditions using different fluctuating temperatures. Graphical comparison between predicted and observed growth and the examination of the relative errors of predictions showed that the model predicted satisfactorily growth under dynamic conditions. Predicted shelf life based on pseudomonads growth was slightly shorter than shelf life observed by sensory analysis with a mean difference of 13.1%. The present study provides a “ready-to-use,” well-validated model for predicting spoilage of aerobically stored ground meat. The use of the model by the meat industry can lead to effective management systems for the optimization of meat quality.Keywords
This publication has 46 references indexed in Scilit:
- The relationship between postmortem urinary catecholamines, meat ultimate pH, and shear force in bulls and cowsMeat Science, 2004
- Fish spoilage bacteria – problems and solutionsCurrent Opinion in Biotechnology, 2002
- Temperatures and ages of boxed beef packed and distributed in CanadaMeat Science, 2002
- Comparison of shelf life of vacuum-packed pork and beefMeat Science, 2002
- Interaction between fish spoilage bacteria Pseudomonas sp. and Shewanella putrefaciens in fish extracts and on fish tissueJournal of Applied Bacteriology, 1996
- Metabolic activities of pseudomonads in batch cultures in extract of minced lambJournal of Applied Bacteriology, 1994
- A dynamic approach to predicting bacterial growth in foodInternational Journal of Food Microbiology, 1994
- Modelling the influence of temperature and carbon dioxide upon the growth of Pseudomonas fluorescensFood Microbiology, 1993
- The Development of Aerobic Spoilage Flora on Meat Stored at Chill TemperaturesJournal of Applied Bacteriology, 1977
- A Selective Medium for the Enumeration of Microbacterium thermosphactum in Meat and Meat ProductsJournal of Applied Bacteriology, 1966