Studying the behaviour of spoilage microbiota on vacuum-packed beef shelf-life as a function of temperature and pH by using predictive modelling, metabolomic and metagenomic tools

Abstract

In Brazil, the rapid deterioration of vacuum-packed beef is one of the current issues that negatively influence an increase of consumption and commercialization of the product in the country and also abroad. The present project is proposed in order to provide scientific data to understand the rapid deterioration of Brazilian vacuum-packed beef during storage and to elucidate the main causes and conditions that lead to the shortening of shelf-life based on the spoilage microbiota studies and its behaviour as a function of temperature and pH conditions and the use of predictive microbiology, metagenomics and metabolomics tools. To do so, the behaviour of the most representative spoilage microbiota (Lactic acid bacteria, Enterobacteriaceae, Carnobacterium spp. and Brochothrix thermosphacta) will be assessed in different vacuum-packed beef cuts (Trapezius toracis, Longissimus dorsi and Psoas major) with range of pH from 5.4 to >6.1, stored at 0 to 7°C. Subsequently, the shelf-life of meat will be quantify at static and fluctuating conditions of time-temperature of storage (from 0 to 10°C) based on the growth of the main spoilage populations which will be described by developing predictive growth models. Finally, a microbial interaction study will be carried out to describe the interactions of spoilage microbiota and its impact on shelf-life of the product. To this end, the antagonistic behaviour of spoilage microbiota will be described at static temperature by using the Lotka-Volterra and Jameson effect models. Growth of spoilage microbiota will be quantified at dynamic conditions of temperatures and pH by the differential form of the Baranyi model and by using the numerical method of Runge-Kutta of 4th order. In addition, the microbial metabolic activities as a result of microbial interactions will be evaluated by using metabolomic tools (HS/SPME-GC/MS). These tools will identify, monitor and quantify the formation of main volatile metabolites over time and correlate them with the main spoilage populations that will be characterized by 16 SrDNA sequencing. This approach will allow describing the dynamic shifts of microbial communities for a better understanding of the mechanisms that lead to the spoilage of meat during storage. The results obtained will be highly useful for the Brazilian meat industry and also for the scientific community since they will provide crucial information for improving production management and marketing of vacuum-packed beef and to implement effective measures aimed at reducing losses associated to meat spoilage.