Short communication: Change of naturally occurring benzoic acid during skim milk fermentation by commercial cheese starters.

This study sought to investigate the change of naturally occurring benzoic acid (BA) during skim milk fermentation by 4 kinds of commercial cheese starters used in domestic cheese. The culture was incubated at 3-h intervals for 24h at 30, 35, and 40°C. The BA content during fermentation by Streptococcus thermophilus STB-01 was detected after 12h at all temperatures, sharply increasing at 30°C. In Lactobacillus paracasei LC431, BA was detected after 9h at all temperatures, sharply increasing until 18h and decreasing after 18h at 30 and 35°C. In the case of R707 (consisting of Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris), BA increased from 6h to 15h and decreased after 15h at 40°C. The BA during STB-01 and CHN-11 (1:1; mixture of S. thermophilus, Lc. lactis ssp. lactis, Lc. lactis ssp. cremoris, Lc. lactis ssp. diacetylactis, Leuconostoc mesenteroides ssp. cremoris) fermentation was detected after 3h at 35 and 40°C, sharply increasing up to 12h and decreasing after 15h at 35°C, and after 6h, increasing up to 9h at 30°C. After 3h, it steadily decreased at 40°C. The highest amount of BA was found during the fermentation by R707 at 30°C; 15h with 12.46mg/kg.