Production of volatile sulfur compounds in Cheddar cheese slurries

The influence of Lactococcus lactis ssp. cremoris S2, Brevibacterium linens BL2 and pure B. Linens BL2 L-methionine γ-lyase (MGL) enzyme on the production of volatile sulfur compounds (VSC) in aseptic cheese slurries was investigated. Cheese curd was prepared with L. lactis ssp. cremoris S2 and by direct acidification with L-glucono δ-lactone. B. linens BL2 and MGL were added to the slurries made by each method. Significant differences (P < 0.0001) in VSC production were observed between slurries made by direct acidification and those made with the starter culture. The methanethiol level decreased in the absence of the starter culture; however, it increased over the first 4 d of incubation in slurries made with L. lactis ssp. cremoris S2. Addition of the starter culture to B. linens BL2 or MGL further increased methanethiol. Production of dimethyltrisulfide was correlated (R² = 0.80) to methanethiol content. Dimethyldisulfide levels increased over time in all slurries prepared with L. lactis ssp. cremoris S2. Addition of free methionine to slurries made from curd prepared with starter resulted in an increase in VSC. Starter bacteria increased methanethiol generation and stabilized the concentration in slurries. Addition of B. linens BL2 and MGL increased methanethiol production.