Numbers and strains of lactobacilli in some probiotic products.

The numbers and types of Lactobacillus strains in probiotic feed or food products for sale in Europe were compared with the information stated on the product labels. The labels of all 10 products gave information on the genus and species of Lactobacillus, and seven gave information on the numbers of a specified strain(s). Lactobacilli were recovered using a recently validated method, developed as part of the European Community Project SMT4 CT98-2235 for the official control of probiotic microorganisms used as feed additives. Polymerase chain reaction (PCR)-based methods were used to assess the accuracy of labelling with regard to genus and species, and pulsed-field gel electrophoresis (PFGE) was used to identify strains. Five products were mislabelled with respect to the numbers and three with respect to species of lactobacilli. In four cases, the specified strains were not detected. Four fermented milks sold under three trademarks contained the same strain, which was named differently on each label. As safety and functionality of probiotics are strain dependent, these results demonstrated the need to control lactobacilli present in commercially probiotic human food products, not only at the species but also at the strain level, to ensure their quality and protect the consumer. The usefulness of the official methods developed for animal feed additives to identify lactobacilli in probiotic foods for humans was demonstrated.