In this study, seven essential oils, cumin (C), marjoram (M), thyme (T),
rosemary (R), lemongrass (L), clove (CL) and citronella (CI) and three
preservatives, tri-sodium phosphate (TSP), sodium lactate (SL) and sodium
acetate (SA) were studied for their antimicrobial effect on the growth of E. coli
O157:H7. Oils of T, M and R and SL gave considerable effectiveness against E.
coli O157:H7. The effect of 21 mixtures from 7 concentrations of T, M or R oils
with SL on E. coli O157:H7 growth was studied. All mixtures had bacteriostitic
and some of them had bactericidal effect. Sensory evaluation for meat patties
containing the mention different mixtures were done to select the highly
acceptable formula. ANOVA indicated that there are high significant differences
(p<0.01) between the different mixtures. Patties contained mixtures of T, M or R
(0.1 and 0.25%) and SL (0.25 and 0.5%) had high score. These mixtures were
selected to complete the study. Results lead to advice that low concentration from
essential oils are accepted for use in minced meat. Minced meat samples were
inoculated by E. coli O157:H7 then treated by selected mixtures and stored at
4+0.5ºC to study quality of refrigerated minced meat. Control minced meat
sample spoiled at 6 days. The treated minced meat samples had shelf life more
than control between 9 and 15 days. Moreover, addition of essential oils minimize
the growth of E. coli O157:H7 in treated minced meat corresponding with control
sample. Finally, thyme, marjoram and rosemary oils can play an important role as
antimicrobial and antioxidant agents in refrigerated minced meat. |
