The enumeration of probiotic issues: From unavailable standardised culture media to a recommended procedure?

Abstract

Probiotic products are becoming increasingly popular worldwide. Regulators and quality control personnel need a clear path to count viable cells within each product. We have reviewed progress on the enumeration of probiotics in foods and supplements. Today, no single culture medium or combination of culture media can accurately enumerate all probiotics available. Culture-independent techniques can speed the counting process compared with traditional agar plating, but their sophistication makes them unsuitable for routine quality control in many laboratories. The enumeration of probiotics in a given product needs to be tailor-made: the response of each probiotic and starter culture used in the food or supplement to a narrow set of culture media should be assessed first to identify the proper conditions for an accurate enumeration. A standardised procedure should be developed in the near future with the consensus of the scientific, industrial and regulator communities.