Effect of citrus fruit (Citrus sinensis, Citrus limon and Citrus aurantifolia) rind essential oils on preservation of chicken meat artificially infected with bacteria

Abstract

Essential oils (EOs) obtained from a wide variety of plants have become popular with increased scientific interest as potential natural agents for food  preservation. Two concentrations of rind EOs (400 mg/ml and 200 mg/ml) from three species of citrus fruit; Citrus sinensis (Sweet orange), Citrus limon  (Lemon), and Citrus aurantifolia (Lime) were used to treat fresh chicken meat inoculated with Escherichia coli ATCC 25922, Salmonella typhi ATCC 20971  and Salmonella enterica ATCC 14028 to evaluate their protective abilities on bacteria-contaminated meat The EOs were extracted from the ground rinds  by hydro-distillation. Alongside the EOs, sodium nitrate (NaNO₃) was used as a positive control preservative. A viable count was carried out to determine  the bacteria load reduction on the inoculated fresh chicken meat. After 24 hours of treatment, the results showed that the EOs had no adverse effect on  the physical attributes of the meat: the color and smell of the chicken meat were unaltered compared with the negative control (None EO and NaNO₃  treated meat) that showed evidence of putrefaction through color change and foul smell. The two- lime rind EOs concentrations used to treat the  Escherichia coli ATCC 25922 inoculated meat reduced the viable count of the organism by 7.9 log compared to the Escherichia coli ATCC 25922-inoculated  meat which received no rind EOs or NaNO₃ treatment. Other results showed that sweet orange (SO) rind EOs (400 mg/ml and 200 mg/ml) treatment of meat inoculated with Salmonella enterica ATCC 14028 had similar but mild preservative effects as both treatments reduced the log of the bacteria by 1.1  and 0.8, respectively. In comparison with NaNO₃, the EOs treatment had a significant (p<0.05) preservative effect on the bacteria-inoculated meats.  Findings from this study, therefore, suggest that Citrus spp. rind EOs have good potential as natural preservative for chicken meat. However,  notwithstanding the relative positive organoleptic results observed in this study, further investigations on the prolonged preservation effect of the EOs  on the physical attributes of fresh chicken meat need to be undertaken.