Development and characterization of lactose-positive Pediococcus species for milk fermentation
Applied and Environmental Microbiology
American Society of Microbiology
Bacteriophagesagainst Streptococcusthermophilus areagrowingproblemintheItaliancheeseindustry.One possiblecontrolmethodinvolvesreplacing S.thermophilus inmozzarellastarterblendswithlacticacidbacteria 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 ATCC12697werethenusedtoexaminelactose-positivepediococci forpropertiesrelatedtomilkfermentation.Bothtransformantsrapidlyproducedacidandefficientlyretained 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.
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.