A centrifugation-based clearing method allows high-throughput acidification and growth-rate measurements in milk

The turbidity of milk prohibits the use optical density measurements for strain characterizations. This often limits research to laboratory media. Here, we cleared through centrifugation remove insoluble solids. resulted in a clear liquid phase, termed serum, which can be used track microbial growth until pH 5.2 is reached. At coagulation soluble protein occurs, making medium opaque again. We found that behavior serum was predictive 39 Lactococcus lactis (R2 = 0.81) and lesser extent 42 Lactiplantibacillus plantarum (formerly Lactobacillus plantarum; R2 0.49) strains. Hence, as an optically alternative comparison metabolic characteristics. Characterization rate, specific acidification rate at wavelength 600 nm, amount acid produced per unit biomass all these strains showed almost could grow milk, with higher rates Lc. compared Lb. Nondairy isolates had lower than dairy isolates. relatively high similar nondairy isolates, opposed ssp. slightly when cremoris. For doubling occurred maximum rate. relation not strains, where remained constant across ranging from 0.2 h?1 0.3 h?1. conclude valuable high-throughput characterization during fermentation.