Tracking heat-resistant, cold-thriving fluid milk spoilage bacteria from farm to packaged product.
Control of psychrotolerant endospore-forming spoilage bacteria, particularly Bacillus and Paenibacillus spp., is economically important to the dairy industry. These microbes form endospores that can survive high-temperature, short-time pasteurization; hence, their presence in raw milk represents a major potential cause of milk spoilage. A previously developed culture-dependent selection strategy and an rpoB sequence-based subtyping method were applied to bacterial isolates obtained from environmental samples collected on a New York State dairy farm. A total of 54 different rpoB allelic types putatively identified as Bacillus (75% of isolates), Paenibacillus (24%), and Sporosarcina spp. (1%) were identified among 93 isolates. Assembly of a broader data set, including 93 dairy farm isolates, 57 raw milk tank truck isolates, 138 dairy plant storage silo isolates, and 336 pasteurized milk isolates, identified a total of 154 rpoB allelic types, representing an extensive diversity of Bacillus and Paenibacillus spp. Our molecular subtype data clearly showed that certain endospore-forming bacterial subtypes are present in the dairy farm environment as well as in the processing plant. The potential for entry of these ubiquitous heat-resistant spoilage organisms into milk production and processing systems, from the dairy farm to the processing plant, represents a considerable challenge that will require a comprehensive farm-to-table approach to fluid milk quality.
Huck
J R
JR
Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA.
Sonnen
M
M
Boor
K J
KJ
D000821:Animal Feed / Q000382:microbiology; D000818:Animals; D001407:Bacillus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification; D001419:Bacteria / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D002417:Cattle; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000737:chemistry; D003612:Dairying / Q000295:instrumentation; D004864:Equipment and Supplies / Q000382:microbiology; D005260:Female; D005511:Food Handling / Q000379:methods; D018857:Food Packaging; D005519:Food Preservation; D006358:Hot Temperature; D006799:Housing, Animal; D008892:Milk / Q000382:microbiology*; D011786:Quality Control; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D021521:Ribotyping; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013171:Spores, Bacterial / Q000502:physiology
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S