The effect of certain lactic acid bacteria on the formation of polycyclic aromatic hydrocarbons in smoked shepherd's cheese

The aim of this thesis is to determine the possible reducing effect of Lactic Acid Bacteria (LAB) with known probiotic properties on the polycyclic aromatic hydrocarbon (PAH) concentrations formed by the fumigation of traditionally smoked Caucasian Shepherd's Cheese. In the experimental design, 4 PAH (benzo [a] pyrene (BaP), benz [a] anthracene (BaA), benzo [a] fluoranthene (BbF), and Chrysene (Chr)) were added during the production of two non-smoked cheese groups (C and D). While the production of the target cheese groups (B and D) was done with the addition of mixed LAB culture containing L. acidophilus, L. plantorum, S.thermophilus and L. bulgaricus strains, only commercial rennet (enzyme) was used in the control groups (A and C). PAH concentrations of group A, B, C and D cheeses were monitored during the ripening processes. On the 3rd, 18th, 30th, 60th, 62nd and 90th days of ripening, the microbiological presence of total LAB counts, total aerobic mesophilic bacteria (TAMB), total mold-yeast; physicochemically, the presence of dry matter, oil, pH, salt and 4 PAH were determined. Significant physicochemical changes were observed according to the effect of fumigation and the cheese ripening process. The 4 PAH levels in detectable samples for all groups decreased by 15.07% for group A, 47.49% for group B; 15.29% for C group and 41.21% for group D based on their arithmetic mean from day 62 for groups A and B, and from day 3 for groups C and D; This decrease was found to be statistically significant (P<0.05). Hence, the presence of PAH formed in traditional smoked cheese samples was reduced by the application of probiotic cultures and was reduced to acceptable limits according to the daily intake limits specified for other foodstuffs. As such, with the addition of LAB to traditional smoked cheeses with PAH risk, a more reliable product that can have a functional effect for the biological detoxification of PAHs, has been developed for human health.