Seasonal occurence of intestinal parasite infection in Lithuanian village dogs

Abstract

Inhibition of food spoilage and pathogenic bacteria in order to extend the shelf life of products is one of the main goals in food industry. Achieving this goal through biopreservation using natural antimicrobial compounds is of considerable interest and attracts special attention of consumers. One of the biggest considerations in biopreservation in recent years is dedicated to lactic acid bacteria (LAB) and bacteriocins produced by them. Safety of bacteriocin-producing LAB, intended to be used for food production, is an important aspect. From the enzymatic point of view, strains should not produce harmful enzymes like β-glucosidase or β-glucuronidase. The aim of this study was to select bacteriocin nisin-producing Lactococcus lactis strains with no activity of β-glucosidase or β-glucuronidase out of 12 nisin producing L. lactis strains, isolated from local cow and goat milk, fermented wheat and buckwheat samples. The enzymatic tests were carried out using the API ZYM kit. No activity of β-glucuronidase was detected, though four strains of plant origin were found to produce strong β-glucosidase activity. Other evaluation of enzymatic activities revealed none or weak activities determined for alkaline phosphatase, esterase (C4), esterase lipase (C8), lipase (C14), valine arylamidase, cysteine arylamidase, trypsin, α-galactosidase, α-glucosidase, N-acetyl-β-glucosaminidase, α-mannosidase, and α-fucosidase. Weak phosphohydrolase activities were determined for all of the strains except one strain isolated from raw goat milk, which had strong activity of this enzyme. Eight nisin-producing L. lactis strains were found to be safe regarding the enzymatic activity, and could be applied for biopreservation after further testing. This research was fund[...].