Assessment of bioactive components of essential oils for antimicrobial activity in the dairy food matrix

Abstract

Essential oils as a whole have been widely investigated for their antimicrobial properties against spoilage microorganisms and pathogens. However limited information is available about the inhibitory activities of components of EO in foods and more specifically in dairy food matrices. The widespread components of common EOs were evaluated for their antibacterial activity in media and skim milk. Amongst the EO components, trans-cinnamaldehyde and eugenol were the most effective on the basis of disk assay and minimum bactericidal concentrations in milk. The MBC of these EOs was unaffected by the conditions of the incubation temperature of milk. However the MBC was decreased in paneer slurry against L.monocytogenes and E. coli O157:H7 when incubated at 7 °C than37 °C. In the dairy spread, trans-cinnamaldehyde and eugenol were effective in inhibiting TBC, coliform, and yeast & mold count at 0.26 mg/g without affecting sensory properties. The microbial load in paneer made from EO added to milk (10 mg/ml) significantly inhibited microbial growth during storage. In addition eugenol has shown antioxidant activity in milk through ABTS radical scavenging assay.