March & April 2004

Apart from their delicious taste what do yoghurt, probiotics, cheese, salami, sauerkraut, and sourdough bread have in common? The answer is starter cultures or more specifically lactic acid including lactobacillus, leuconostoc, streptococcus and paediococcus bacteria. Traditionally these foods have been prepared using mixed cultures based on microbial populations that proliferate on the surface of these foods. The main drawback of culturing these foods with 'native mixed strains' is the unpredictable quality and limited storage life due to natural spoilage organisms that are present.

This was the trigger for the development and application of pure bacterial starter cultures for use in these foods. The largest sector of the starter cultures business is cheese, including Lactobaccilli for yellow cheeses, external moulds [P. camemberti] for camembert and brie, internal moulds [P. roqueforti] for stilton and gorgonzola. Yoghurt cultures include S. thermophilus, L. bulgaricus and L. helveticus. The more 'modern' yoghurts termed probiotics include Bifidobacteria, L. acidophilus, L. casei, L GG and L. plantarum. Bacterial strains in meat products include L. plantarum, P. cerevisiae as well as Penicillium moulds on the surface of salami sausages. Probiotics have become popular ingredients in feed for young livestock [calves, piglets]. These are mainly lactic acid bacteria which implant themselves in the gut and excrete lactic acid which reduces its pH thereby inactivating many infection-causing pathogens. infections.

Over 20 companies produce starter cultures and probiotics and the present worldwide market at several hundred million dollars, is predicted to increase almost 50% by 2010. Further details of this dynamic fermentation and biotechnology sector can be read in our survey: 'Starter Cultures & Probiotics - Markets and Opportunities by 2010'.

Protein hydrolysates and peptones are ingredients for the nutrition of:

• microorganisms in culture and fermentation media
• infants
• invalids, dietetic patients and sportsmen