Our topic for this blog is the use of probiotic starter cultures in plant based cheese making. One of the interesting things about being a plant based cheese maker is that we don’t have generations of past experience to draw upon. It is a relatively new food application that has emerged in parallel with the recent increased interest in a vegan or plant based diet. So what can we learn from previous generations of dairy cheesemakers, or from the makers of other fermented foods such as kombucha or sauerkraut or tempeh? The answer is quite a lot, of course.
Making cheese from cashew nuts is not too different to making it from dairy milk. Both use lactic acid fermentation to assist with preservation. Fermentation is achieved by adding special lactic acid bacteria (LAB) starter cultures to the raw ingredients. LAB are named because, in dairy cheese production, the primary food source for the bacteria is lactose, which is a simple sugar (carbohydrate) found in milk. LAB produce lactic acid which lowers the pH. The low pH, combined with the removal of much of the liquid (through draining of the whey and pressing the curd) and the addition of some salt all helps to preserve the newly made cheese, through inhibiting the growth of undesirable organisms.
The three conditions of low pH, low water activity and adequate salt are the cornerstones of food safety in fermented foods. Some products may have a high water activity and low salt level, but low pH, eg kombucha, others may have a higher pH but low water activity and high salt eg salami so there is definitely no "one size fits all" set of conditions.
In producing our cultured nut cheese, there is no “curds and whey” stage. Vegan friendly LAB starter cultures are added to the cashews after grinding and the bacteria metabolise simple sugars such as glucose, galactose or sucrose, rather than lactose, to produce lactic acid. The fermented cashew cheese is then place in moulds and matured as required.
Conventional dairy cheese makers have access to a considerable array of starter cultures each of which have been developed to include specific strains of bacteria. In addition to the acid production, these cultures also impart specific properties to the flavour and body of the cheese. Different strains are used in the production of hard versus soft versus white or blue moulded cheeses. Other cultures may be used alongside the starter to further enhance the ripening or flavour of certain cheese styles.
These cultures are almost invariably grown using milk as a nutrient and finding vegan alternatives is a significant challenge. Some plantbased cheesemakers use rejuvelac which is made by soaking sprouted grains such as wheat or quinoa until the soaking liquid is fermented, or they may use yoghurt, or kombucha or sauerkraut juice. All of these alternatives are good sources of LAB. Artisa uses a dairy free starter culture that contains a mix of LAB strains - Lactobacillus, Streptococcus and Bifidobacterium. Once again, it is apparent that production systems are customised by individual cheesemakers to meet their own requirements.
Having come from a science background, it is all of the research and development and sharing of information that I see going on in the plant based cheesemaking community, both locally and internationally, that is one of the most satisfying parts of my job. We are all learning together, so we can make a dairy free future just that little bit more delicious!