ABSTRACTMalolactic fermentation (MLF) is a biochemical transformation conducted by lactic acid bacteria (LAB) that occurs in wine at the end of alcoholic fermentation.Oenococcus oeniis the main species responsible for MLF in most wines. As in other fermented foods, where bacteriophages represent a potential risk for the fermentative process,O. oenibacteriophages have been reported to be a possible cause of unsuccessful MLF in wine. Thus, preparation of commercial starters that take into account the different sensitivities ofO. oenistrains to different phages would be advisable. However, currently, no methods have been described to identify phages infectingO. oeni. In this study, two factors are addressed: detection and typing of bacteriophages. First, a simple PCR method was devised targeting a conserved region of the endolysin (lys) gene to detect temperateO. oenibacteriophages. For this purpose, 37O. oenistrains isolated from Italian wines during different phases of the vinification process were analyzed by PCR for the presence of thelysgene, and 25 strains gave a band of the expected size (1,160 bp). This is the first method to be developed that allows identification of lysogenicO. oenistrains without the need for time-consuming phage bacterial-lysis induction methods. Moreover, a phylogenetic analysis was conducted to type bacteriophages. After the treatment of bacteria with UV light, lysis was obtained for 15 strains, and the 15 phage DNAs isolated were subjected to two randomly amplified polymorphic DNA (RAPD)-PCRs. By combining the RAPD profiles andlyssequences, 12 differentO. oeniphages were clearly distinguished.