The stability of probiotics is currently a significant barrier to their use in non-dairy applications. Most probiotic foods on the market are dairy-based because of the established use of bacteria in yoghurt.
In other foods however, heat, humidity and other processing conditions can all destroy the bacteria, which scientists believe must be alive to have an effect on health.
But suppliers working on technologies to protect the bacteria say there are ways of getting around these hurdles to produce a range of innovative products.
Canadian probiotics company Institut Rosell, which claims to be the leading supplier of probiotics to dietary supplements, says it has tested the stability of its coated probiotics in products ranging from chocolate bars to energy tablets.
In a trial on chocolate pralines stored at room temperature for six months, 86 per cent of probiotics survived the test period, according to the privately held firm.
"We have done lots of work on chocolate products and there is strong interest from this sector," Caroline Arnaud, technical support manager at the Lallemand business, told NutraIngredients.com.
Technically chocolate is a good vector for probiotics, according to Arnaud, as it does not require much humidity during processing. This could allow manufacturers to develop chocoate-coated nutrition bars or probiotic chocolate drops for addition to cereals.
Such products are currently being tested by clients and some may be ready for market launch next year, said Arnaud.
Adding probiotic bacteria late in the processing stage, through a chocolate coating for example, is also significantly easier than early on in formulation.
Foods that need to be baked, like cereal bars, require a higher level of protection, and while a prototype bar has been developed by competitor Danisco (under the former Rhodia ownership), technological issues still present problems when producing the finished product.
Manufacturers incorporating the bacteria early on are also put off by risk of contamination with other products made on the same line.
"Bacteria frightens food companies. They don't want to integrate these materials across food processes, even if they are good bacteria. So if a confectionery company was making different products on the same line, introducing water to the plant to wash it down would present difficulties for use of the bacteria afterwards," explained Arnaud.
Other foods being tested by several suppliers include infant formula and fruit juice, already available under brands like ProViva.
But while more probiotic products begin to emerge on the market, and suppliers continue to make new claims for the stability of their strains, most agree that there is to date no technology offering guaranteed stability across all strains and processes.
"The stability really is a factor that is very limiting today," said Arnaud. "Nobody has yet worked out how to combat humidity."
Probiotics product manager at Danisco Siegbert Philipp adds: "There is no coating technology on the market today that is a miracle. One coating cannot fulfil all the requirements - it often doesn't work for all strains in all technical processes."