Meat fermentation at mini-scale: Laboratory methods to study starter cultures

Fermentation is a traditional and economical way to preserve and enhance the quality of meat. The process is a complex biological chain of events mediated by a shifting balance of dominant microorganisms. These convert carbohydrates into organic acids that quickly acidify the meat environment, leading to further changes in sensory and textural properties. Managing the microbiome is key to determining the characteristics of products. Fermented meats are produced in many countries. The sausage format typified by salami is common, as is whole leg muscle turned into ham. Their diverse flavours and textures reflect regional differences in ingredients, climate conditions (temperature, humidity, airflow, storage) and environmental microorganisms. For authentically traditional processing, the growth of indigenous microbes is encouraged, and additional starter cultures are not used (Coppola et al. 2000; Talon et al. 2007). However, environmental microbes are an uncontrolled variable. They may have poor enzyme functions (e.g. nitrite reductase, or the lipases and proteases responsible for flavour development), or have weak resistance to the curing salt, or be outcompeted by less desirable strains. Producing consistently high quality fermented food relies on some luck, even in the hands of artisan manufacturers. There is an opportunity to expand the roles that microbes can play in meat fermentation, in effect to teach them new tricks. This is an aim of a New Zealand government-sponsored MBIE Endeavour Research Programme called “Accelerated Evolution: A step-change in food fermentation”. Our researchers and industry partners are interested in how indigenous and commercialised strains can be stimulated to acidify better, generate novel flavour compounds, provide stronger defence against pathogens, and be biological substitutes for chemical additives.