Summary:

Biofilms in meat processing plants provide a reservoir for contamination with pathogenic and spoilage organisms. Biofilms are surface-attached three-dimensional structures formed by diverse bacteria that are embedded in an extracellular polymeric matrix. Biofilm communities resist cleaning and sanitation because biofilm matrix provides a diffusion barrier to sanitation agents and thus protects bacterial cells. The meat industry and suppliers of equipment to the meat industry aim to control biofilm formation by hygienic design of processing equipment and –facilities; however, these efforts fail to fully control the problem. 

Biofilms in fresh meat processing plants host microorganisms that are relevant for meat spoilage but also pathogens such as Salmonella as well as Shiga-toxin producing Escherichia coli and may contaminate meat with pathogens. Biofilms in facilities producing ready-to-eat meat products host Listeria monocytogenes. For example, a single strain of L. monocytogenes persisted in the processing plant for a period of five years as demonstrated by whole genome sequencing. The composition of biofilm communities in meat processing plants also overlaps significantly with the spoilage microbiota of fresh or RTE meats, however, strain-level evidence that spoilage microbiota is derived from biofilm communities is currently unavailable. It thus remains unknown how transfer of microbes from biofilms to food contact surfaces and products occurs, or can be efficiently interrupted. The proposed project aims to address this gap in knowledge by using a combination of culture-dependent and culture-independent, sequence based methodologies to study the transfer of biofilm-embedded microbes in meat processing plants, and to provide strain level information whether biofilm communities overlap with spoilage organisms. This information will be used to evaluate novel methods for contamination of meat to extend the shelf life of vacuum-packaged primal cuts. 

This project will evaluate the efficacy of novel sanitation methods including ozone nano-bubbles and of plasma nano-bubbles on the inactivation of meat plant microbiota. Nanobubbles have unique characteristics that lead to promising applications in delivering antimicrobial sanitization agents. In contrast to chlorine-based sanitizers, ozone can be used on product contact surfaces during operation and on meat. The direct comparison of ozone nano-bubbles to plasma nano-bubbles allows the fine-tuning of sanitation efficacy by adjusting the composition of active compounds in nano-bubbles. 

Export of Canadian primal cuts to markets in Europe and Asia requires a shelf life of at least two months while stored at -1 °C. Achieving and extending this shelf life requires control of bacterial contamination of primal cuts during processing. Moreover, the type of contamination determines whether microbial growth causes spoilage, or not: Growth of Carnobacterium species is generally not associated with sensory changes of the product while growth of Enterobacterales, Brochotrix and Clostridium species results in bloating of the packages and off odors. Extending the shelf life of vacuum packages primal cuts with novel technologies that target spoilage organisms will increase the competitiveness of the Canadian meat industry by reducing costs associated with the supply chain, and by reducing food waste.