Determination of menaquinone production by Lactococcus spp. and propionibacteria in cheese

Two genera of lactic acid bacteria are principally known to produce menaquinones in cheese: Lactococcus spp. in semi-hard cheese such as Vacherin Fribourgeois and Raclette, and propionibacteria in Swiss-type cheese such as Emmental. Menaquinone (MK) content of several cheese loaves was analysed to determine the impact of sampling site, ripening time and cultures used during cheese making. With Lactococcus spp., in Vacherin and in Raclette, the principal menaquinone was MK-9 (median = 149 μg kg−1 and median = 167 μg kg−1) followed by MK-8 (median = 70 μg kg−1 and median = 66 μg kg−1). In Emmental cheese, the principal menaquinone was MK-4 (median = 48 μg kg−1) in young cheese and MK-9(4H) (median = 468 μg kg−1) in cheese older than 90 days. The only difference in sampling site was found in Raclette for MK-9. In Vacherin, MK-8, MK-9 and total contents of menaquinones were significantly different according to the strain of Lactococcus lactis ssp. cremoris used.