Evaluation of a Microbiological Reference Standard (EZ-Accu ShotTM) as Test Material for Proficiency Testing (PT) Scheme in the Breweries.

A commercially available lactic acid bacteria (LAB) reference standard (EZ-Accu Shot^TMLactobacillus rhamnosus) was evaluated for its suitability to be used in the microbiological proficiency test (PT) schemes that are utilized within brewery microbiological quality systems and protocols. The test material was evaluated for homogeneity, stability, and culturability on several routinely used beer-spoiler detection media using membrane filtration (MF). Mean numbers of CFUs were calculated and subjected to statistical analysis. The coefficient of variation (CV) value in the homogeneity test (10.6%) showed that the test material was sufficiently homogenous, and the pellet-to-pellet variation was acceptable. The P-value in the stability and culturability test (p > 0.05) showed no statistically significant differences between variables, indicating that the microorganisms in the pellet would be stable during long storage and transport and that the culturability on different beer-spoiler detection media are comparable. In conclusion, this study suggests that EZ-Accu Shot^TML. rhamnosus is suitable as a test material for microbiological PT schemes in breweries. [ABSTRACT FROM AUTHOR]