“…However, nck202.50 continued to be sensitive to restriction by other lactococcal R/M systems of different specificity from LlaI (Alatossava & Klaenahmmer, 1991). Since then, the approach has been adopted worldwide with considerable success (Jarvis, 1988(Jarvis, , 1989Kelly et al, 1990;Powell et al, 1990;Harrington & Hill, 1991;Gireesh et al, 1992;Ward et al, 1992;Coakley et al, 1997;Pillidge et al, 2000;Trotter et al, 2001;Mills et al, 2002). Conjugal strategies have also been used to combine more than one mechanism in a single strain (Klaenhammer, 1987;Coffey et al, 1989;Klaenahmmer, 1991;Sing & Klaenhammer, 1993;O'Sullivan et al, 1998).…”