Selective method for the isolation of Sporolactobacillus from food and environment sources

A detection procedure was developed in which a modified Lactobacilli MRS medium was used to enrich for Sporolactobacillus from a variety of foods, feed soil and environmental samples. Each sample was rinsed with 50 ml of a modified Lactobacilli MRS broth containing 1.0% (w/v) alpha-methyl glucoside 0.1% (w/v) potassium sorbate, 0.00224% (w/v) bromocresol green indicator, adjusted to pH 5.5 with acetic acid and incubated at 37 degrees C for 7 d under 5% CO2. Volumes of 2 ml from each sample were heat shocked at 80 degrees C for 5 min and 0.1 ml spread onto plates of Lactobacilli MRS agar (Difco), pH 5.5 and APT agar (BBL), pH 5.5. Plates were incubated for 5 d and suspect colonies were tested for catalase production, benzidine reaction, nitrate reduction, motility and Gram stain reaction. This method was demonstrated to be selective for Sporolactobacillus.