1. Modeling the Growth and Interaction Between Brochothrix thermosphacta, Pseudomonas spp., and Leuconostoc gelidum in Minced Pork Samples
- Author
-
Bernard Taminiau, Assia Tahiri, Georges Daube, Frédéric Farnir, Laurent Delhalle, Emilie Cauchie, Papa Abdoulaye Fall, N. Korsak, Sophie Burteau, and Ghislain Baré
- Subjects
Microbiology (medical) ,Food spoilage ,lcsh:QR1-502 ,Pseudomonas fluorescens ,growth parameters ,Bacterial growth ,Shelf life ,Microbiology ,lcsh:Microbiology ,03 medical and health sciences ,predictive microbiology ,Pseudomonas fragi ,interaction models ,Leuconostoc gelidum ,Food science ,030304 developmental biology ,Original Research ,0303 health sciences ,biology ,030306 microbiology ,Chemistry ,Pseudomonas ,biology.organism_classification ,Jameson-effect model ,Food packaging ,Modified atmosphere ,Lotka Volterra model ,Brochothrix thermosphacta ,Pseudomonas spp - Abstract
The aim of this study was to obtain the growth parameters of specific spoilage micro-organisms previously isolated in minced pork (MP) samples and to develop a three-spoilage species interaction model under different storage conditions. Naturally contaminated samples were used to validate this approach by considering the effect of the food microbiota. Three groups of bacteria were inoculated on irradiated samples, in mono- and in co-culture experiments (n = 1152): Brochothrix thermosphacta, Leuconostoc gelidum, and Pseudomonas spp. (Pseudomonas fluorescens and Pseudomonas fragi). Samples were stored in two food packaging [food wrap and modified atmosphere packaging (CO2 30%/O2 70%)] at three isothermal conditions (4, 8, and 12°C). Analysis was carried out by using both 16S rRNA gene amplicon sequencing and classical microbiology in order to estimate bacterial counts during the storage period. Growth parameters were obtained by fitting primary (Baranyi) and secondary (square root) models. The food packaging shows the highest impact on bacterial growth rates, which in turn have the strongest influence on the shelf life of food products. Based on these results, a three-spoilage species interaction model was developed by using the modified Jameson-effect model and the Lotka Volterra (prey-predator) model. The modified Jameson-effect model showed slightly better performances, with 40-86% out of the observed counts falling into the Acceptable Simulation Zone (ASZ). It only concerns 14-48% for the prey-predator approach. These results can be explained by the fact that the dynamics of experimental and validation datasets seems to follow a Jameson behavior. On the other hand, the Lotka Volterra model is based on complex interaction factors, which are included in highly variable intervals. More datasets are probably needed to obtained reliable factors, and so better model fittings, especially for three- or more-spoilage species interaction models. Further studies are also needed to better understand the interaction of spoilage bacteria between them and in the presence of natural microbiota.
- Published
- 2020
- Full Text
- View/download PDF