Using a modification of ASTM D4012 as a quality control tool for Bacillus spp. spore preparations.

Bacillus endospore concentrates are used widely as probiotics for aquaculture.  Traditionally, culture test methods have been used to determine both the endospore concentration (in CFU g^-1) and the endospore to vegetative cell ratio in finished product. As with all culture tests, the protocol used to enumerate Bacillus endospores entails a 24h to 48h delay between time of test initiation and time of data availability.  Additionally, cell/endospore clumping and growth medium selectivity can cause CFU yields to underestimate the endospore-product’s actual cell density.  This paper reports the development of an adenosine triphosphate (ATP) protocol used to determine total ATP-biomass and endospore to vegetative cell ratios in Bacillus sp. endospore-based products.