Troubleshooting high laboratory pasteurization counts in organic raw milk requires characterization of dominant thermoduric bacteria, which includes non-sporeformers as well as sporeformers

• Published in: Journal of dairy science 2024-01
• Main Authors: Lee, Renee T, Evanowski, Rachel L, Greenbaum, Halle E, Pawloski, Deborah A, Wiedmann, Martin, Martin, Nicole H
• Format: Article
• Language: English
• ISSN: 1525-3198
• DOI: 10.3168/jds.2023-24330

Laboratory Pasteurization Count (LPC) enumerates thermoduric bacteria and is one parameter used to assess raw milk quality. While there is currently no regulatory limit for LPC, LPC data are used by some dairy processors and cooperatives to designate raw milk quality premiums paid to farmers and may also be used for troubleshooting bacterial contamination issues. Despite occasionally being used as a proxy for levels of bacterial spores in raw milk, there is limited knowledge of the types of organisms that are enumerated by LPC in contemporary raw milk supplies. While historical studies have reported that thermoduric bacteria quantified by LPC may predominantly represent Gram-positive cocci, updated knowledge on microbial populations enumerated by LPC in contemporary organic raw milk supplies is needed. To address this gap, organic raw milk samples from across the United States (n = 94) were assessed using LPC, and bacterial isolates were characterized. LPC ranged from below detection (