Elucidating Contamination Routes of Meat Spoilage Bacteria with Next Generation Sequencing Methods

Thursday, 30 March 2017: 11:30
Arc (The Square)
Johanna Björkroth, University of Helsinki, Helsinki, Finland
Food processing chains create specific man-made niches for bacteria. Lately, by implementing culture-independent technologies, we have carried out studies aiming at understanding the complexity of microbial ecology associated specifically with food chains. Yet we are still quite far from comprehensive views on how microbes contaminate our foods during primary production, harvesting and processing even though more holistic research approaches are available.

To prevent perishable foods from spoiling, the modern food industry is applying two major hurdles, i.e. refrigerated temperatures and carbon dioxide. They are the main selective pressures having an effect on food spoilage organisms growing in perishable foods packaged under modified atmospheres and cold stored throughout the distribution chains from manufacturers to consumers. Food processing facilities are also refrigerated to maintain food temperatures during manufacture within the limits set by the authorities. Meat processing provides one example of a strictly regulated food chain. Although some variation exists in regulatory temperature limits globally, the temperature of meat during cutting should not generally rise to above 7°C. Therefore meat processing facilities are maintained at 4°C to 12°C. In addition to chilling, strict washing and hygiene practices shape the microbial communities within these premises.

Perishable food items are increasingly manufactured “case ready” allowing retail distributors to place readymade packages on shelves. This omits handling of the food in shops and has been an increasing trend in many countries especially what comes to meat products. From the microbial ecology perspective, microbiomes in these packages are developing through time-dependent succession which is also associated with development of spoilage chages.

Food processing facilities and minimally-processed packaged foods are specific niches for bacterial growth. The selective pressures affecting bacteria in these niches are man-made rather than nature driven. We do not fully understand how cold-tolerant bacteria contaminate food processing facilities and persist in them. Neither do we know the main factors behind microbial succession even though we have been able to recognize the prevailing species present in foods for decades. In my talk I will be walking you through of one of our comprehensive spoilage problem analysis carried out using 16S rRNA gene amplicon analysis. We showed how different harmful bacteria (both pathogens and spoilage bacteria) had their own “behavioral patterns” what comes to the contamination within the processing facility and the subsequent growth in food. According to our study 16S rRNA gene amplicon analyses provide useful information of microbial ecology of a processing site and how this data can help manufacturers solving problems associated with their products.