Nowadays,as the interest in natural preservatives increases,research on bioprotective cultures that produce bacteriocins and studies on the use of these cultures in foods are also increasing day by day.Present study a...Nowadays,as the interest in natural preservatives increases,research on bioprotective cultures that produce bacteriocins and studies on the use of these cultures in foods are also increasing day by day.Present study aimed to investigate bacteriocin characterization and safety of Enterococcus faecium H108,H206 isolates and their potential utilization in the reduction of Listeria monocytogenes ATCC7644 in Beyaz cheese.Enterocin producing E.faecium H108 and H206 strains were isolated from raw cow’s milk and identified by 16S rRNA sequencing.Enterocin containing supernatants of E.faecium H108 and H206 were found to be stable to heat various chemicals used in food industry,wide pH range,lysozyme and catalase enzymes.On the other hand,activity of enterocins were inactivated by proteolytic enzymes.Maximum activity of E.faecium H108 was 6400 AU/mL,while that of H206 was 12800 AU/mL,and the activities remained stable for 24 h.Supernatant of both E.faecium H108 and H206 inhibited L.monocytogenes growth in vitro.E.faecium H108 and H206 did not show haemolytic and DN-ase activities and were susceptible to most of the antibiotics tested.The isolates were used in Beyaz cheese and were found to significantly,but not completely inhibit L.monocytogenes growth.The findings of this research suggest that E.faecium H108 and H206 isolates,after a detailed safety assessment,might be employed as bioprotective cultures in Beyaz cheese with starter culture or hurdle technologies.展开更多
White brined cheese is one of the most produced and consumed cheese varieties in Mediterranean region.Beyaz cheese is a type of white brined cheese and is usually produced from pasteurized cow’s milk.Cheese produced ...White brined cheese is one of the most produced and consumed cheese varieties in Mediterranean region.Beyaz cheese is a type of white brined cheese and is usually produced from pasteurized cow’s milk.Cheese produced from raw milk or contaminated after production with foodborne pathogens may have a safety risk.Beyaz cheese provides a favorable environment for growth of Listeria monocytogenes,a psychrotrophic pathogen.Objective of this study was to evaluate use of nisin producing autochtonous Lactococcus lactis L54 to control L.monocytogenes ATCC 7644 in Beyaz cheese during storage for 90 days.Characterization of bacteriocin demonstrated that nisin L54 has a broad inhibition spectrum on both pathogens including L.monocytogenes ATCC 7644,Staphylococcus aureus ATCC 43300,Bacillus cereus ATCC 33019 and several other lactic acid bacteria strains.The safety assessment revealed that L.lactis L54 did not contain tested virulence genes and showed no hemolytic and DNAse activity.Inoculation of L.lactis L54 to Beyaz cheese significantly decreased the L.monocytogenes counts compared to the control and did not show any negative effect on the physicochemical and sensory properties.L.lactis L54 strain was concluded as potential bioprotective,starter or co-starter culture for Beyaz cheese production.展开更多
基金funded by Ataturk University Research Centre,grant number FHD-2023-13027.
文摘Nowadays,as the interest in natural preservatives increases,research on bioprotective cultures that produce bacteriocins and studies on the use of these cultures in foods are also increasing day by day.Present study aimed to investigate bacteriocin characterization and safety of Enterococcus faecium H108,H206 isolates and their potential utilization in the reduction of Listeria monocytogenes ATCC7644 in Beyaz cheese.Enterocin producing E.faecium H108 and H206 strains were isolated from raw cow’s milk and identified by 16S rRNA sequencing.Enterocin containing supernatants of E.faecium H108 and H206 were found to be stable to heat various chemicals used in food industry,wide pH range,lysozyme and catalase enzymes.On the other hand,activity of enterocins were inactivated by proteolytic enzymes.Maximum activity of E.faecium H108 was 6400 AU/mL,while that of H206 was 12800 AU/mL,and the activities remained stable for 24 h.Supernatant of both E.faecium H108 and H206 inhibited L.monocytogenes growth in vitro.E.faecium H108 and H206 did not show haemolytic and DN-ase activities and were susceptible to most of the antibiotics tested.The isolates were used in Beyaz cheese and were found to significantly,but not completely inhibit L.monocytogenes growth.The findings of this research suggest that E.faecium H108 and H206 isolates,after a detailed safety assessment,might be employed as bioprotective cultures in Beyaz cheese with starter culture or hurdle technologies.
基金funded by Ataturk University Research Center,grant number FDK-2020-8554.
文摘White brined cheese is one of the most produced and consumed cheese varieties in Mediterranean region.Beyaz cheese is a type of white brined cheese and is usually produced from pasteurized cow’s milk.Cheese produced from raw milk or contaminated after production with foodborne pathogens may have a safety risk.Beyaz cheese provides a favorable environment for growth of Listeria monocytogenes,a psychrotrophic pathogen.Objective of this study was to evaluate use of nisin producing autochtonous Lactococcus lactis L54 to control L.monocytogenes ATCC 7644 in Beyaz cheese during storage for 90 days.Characterization of bacteriocin demonstrated that nisin L54 has a broad inhibition spectrum on both pathogens including L.monocytogenes ATCC 7644,Staphylococcus aureus ATCC 43300,Bacillus cereus ATCC 33019 and several other lactic acid bacteria strains.The safety assessment revealed that L.lactis L54 did not contain tested virulence genes and showed no hemolytic and DNAse activity.Inoculation of L.lactis L54 to Beyaz cheese significantly decreased the L.monocytogenes counts compared to the control and did not show any negative effect on the physicochemical and sensory properties.L.lactis L54 strain was concluded as potential bioprotective,starter or co-starter culture for Beyaz cheese production.
