Bacteriophages against Streptococcus thermophilus are a growing problem in the Italian cheese industry. One possible control method involves replacing S. thermophilus in mozzarella starter blends with lactic acid bacteria from a different genus or species. In this study, we evaluated lactose-positive pediococci for this application. Because we could not identify any commercially available pediococci with fast acid-producing ability in milk, we transformed Pediococcus pentosaceus ATCC 25744, P. pentosaceus ATCC 25745, and Pediococcus acidilactici ATCC 12697 by electroporation with pPN-1, a 35-kb Lactococcus lactis lactose plasmid. Transformants of P. pentosaceus ATCC25745and P. acidilactici ATCC12697 were then used to examine lactose-positive pediococci for properties related to milk fermentation. Both transformants rapidly produced acid and efficiently retained pPN-1 in lactose broth, and neither bacterium was attacked by bacteriophages in whey collected from com- mercial cheese facilities. Paired starter combinations of Pediococcus spp. and Lactobacillus helveticus LH100 exhibited synergistic pH reduction in milk, and small-scale cheese trials showed that these cultures could be used to manufacture part-skim mozzarella cheese. Results demonstrate that lactose-positive pediococci have potential as replacement cocci for S. thermophilus in Italian cheese starter blends and may facilitate develop- ment of new strain rotation schemes to combat S. thermophilus bacteriophage problems in mozzarella cheese plants.
Article
Development andcharacterization of lactose-positive Pediococcus species for milk fermentation
Applied and Environmental Microbiology
Document Type
Article
Publisher
American Society of Microbiology
Publication Date
1-1-1996
Disciplines
Abstract
Citation Information
Caldwell, S., D. J. McMahon, C. J. Oberg, and J. R. Broadbent. 1996. Development and
characterization of lactose-positive Pediococcus species for milk fermentation. Appl. Environ.
Microbiol. 62:936-941.