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Increasing phage resistance of cheese starters : a case study using Lactococcus lactis DPC4268
Author(s) -
Coakley,
McGarry,
Fitzgerald,
Ross
Publication year - 1998
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.1998.00268.x
Subject(s) - lactococcus lactis , lytic cycle , bacteriophage , biology , microbiology and biotechnology , plasmid , starter , lactococcus , genetics , bacteria , virus , food science , gene , escherichia coli , lactic acid
This study serves as an example of strategies used to increase the phage resistance of an important Irish Cheddar cheese starter, Lactococcus lactis DPC4268. It describes the emergence and persistence of a lytic bacteriophage, 4268, that has a relatively large burst size and exhibits no homology to the most common phage types encountered in Irish cheese plants. Inherent difficulties were encountered that prevented the effective introduction of conjugative phage‐resistance plasmids pNP40 and pMRC01 to strain DPC4268. In fact, pNP40‐associated Abi systems were naturally present in six of 19 starters. Control of phage 4268 was eventually achieved by generating a mutant of DPC4268, which was subsequently used for cheese manufacture.