Antimicrobial activity of essential oils against Vancomycin-Resistant enterococci (VRE) and Escherichia coli O157:H7 in feta soft cheese and minced beef meat

Abstract

Eleven essential oils (EOs) were evaluated for their antibacterial properties, against Vancomycin-Resistant Enterococci (VRE) and E. coli O157:H7. EOs were introduced into Brain Heart Infusion agar (BHI) (15ml) at a concentration of 0.25 to 2% (vol/vol) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each pathogen evaluated. Results showed that the most active essential oils against bacteria tested were thyme oil, with MIC 90 and MBC 90 for the VRA strains of 0.25% and 0.5%, respectively. Eucalyptus, juniper and clove oils were the least potent agent, with MIC 90 and MBC 90 of 2%. Furthermore, the inhibitory effect of these EO were evaluated against VRE and E. coli O157:H7, experimentally inoculated (10 3 cfu/g) in Feta soft cheese and minced beef meat, which was mixed with different concentrations (0.1%, 0.5% and 1%) of the EO and stored at 7 °C for 14 days. Out of eucalyptus, juniper, mint, rosemary, sage, clove and thyme oils tested against target bacteria sage and thyme showed the best results. Clove and mint did not show any effect on VRE and E. coli O157:H7 in both kinds of studied foods. The addition of thyme oil at concentrations of 0.5 and 1% caused best significant reduction in the growth rate of VRE and E. coli O157:H7 in cheese and meat at 7 o C. It is concluded that selected plant EOs can act as potent inhibitors of both microorganisms in a food product.The results revealed the potential of thyme oil as a natural preservative in feta soft cheese and minced beef meat against VRE and E. coli O157:H7 contamination.

Antibacterial activity of Thymus capitatus and Thymus algeriensis essential oils against four food‐borne pathogens inoculated in minced beef meat

“…The obtained results were in accordance with previous work by Selim (), which has confirmed the antibacterial efficiency in situ of thyme EO against E. coli inoculated in minced beef meat at 3 log CFU/g. In this case, the study of Selim (), demonstrated that the thyme EO, particularly from the concentration of 0.5 and 1% (vol/wt) can reduce the population‐level of the foodborne pathogen ( E. coli O157: H7). Thus, a bactericidal effect was obtained only after 3 days of storage.…”

“…In fact, the initial populations of the pathogen (8 log CFU/g) on the untreated samples (control) were significantly increased and reached to 9.83 log CFU/g, after 15 days of storage. The obtained results were in accordance with previous work by Selim (2011), which has confirmed the antibacterial efficiency in situ of thyme EO against E. coli inoculated in minced beef meat at 3 log CFU/g.…”

Production and characterisation of skate skin gelatin films incorporated with thyme essential oil and their application in chicken tenderloin packaging

“…After 10 days, the population of E. coli O157:H7 in the control sample was 6.10 log CFU g −1 , whereas the microbial count in the chicken tenderloin samples wrapped with the SSG–TEO film was 3.59 log CFU g −1 . Selim () also reported that the populations of E. coli O157:H7 in cheese and beef meat during storage at 7 °C for 14 days were significantly decreased by the addition of TEO. These results suggest that the addition of TEO into the SSG film could be an effective antimicrobial packaging method for chicken tenderloin.…”

Prevalence and Characterization of Shiga-Toxin O157:H7 and Non-O157:H7 EnterohemorrhagicEscherichia ColiIsolated from Different Sources

“…Ground beef and other bovine products have often been implicated as sources of Stec (27), along with other food products (2,53,54). occasional outbreaks of Stec have also been associated with public drinking water (55) and swimming in contaminated water (25,28,46).…”