Meat products are ideal medium for bacteria because of high moisture content, richness in nitrogenous compounds. Twenty five random samples of minced meat were collected from different supermarkets in, Menofia governorate. All collected samples were subjected to bacteriological examination for aerobic plate count, coliform Enterobacteriacea, Staphylococci count and detection of,staph .aureus organisms. Also twelve samples of minced beef were collected from different butcher shops in Menofia governorate were divided into untreated (control) and treated samples which homogenized with thyme oils in 0.5%, 1% and 1.5% concentrations. Each sample was analyzed bacteriological promptly during cold storage until spoilage for studying the antimicrobial efficiency of Thyme oil in minced beef. Mean value of Aerobic Plate Count, coliforms Enterobacteriaceae and Staphylococci count of the examined minced beef were 6.52x 104 0.27x 104 , 7.8x102 0.15x102 , 5.82×102 ± 1.02×102. and 6.15×102 ± 1.36×102 respectively. Seven strains of Coagulase + ve S.aureus , and Staphylococcus epidermidis, were isolated while 2 strains of Staphylococcus saprophyticus , Staphylococcus intermedius Staphylococcus capitis and Micrococcispp .were isolated from examinad samples. In case of using thyme oil at the concentrations 0.5%, 1% and 1.5% the scores of sensory evaluation were 9,9 , 8, 6 ,5& 9 ,9, 8, 7,6 & 9,9,8,8 , 7after zero day, 1 st day, 2 nd day ,3rd day and 4th day of the cold storage period respectively, comparing to the scores of sensory evaluation in the control samples which were 9, 6,5,4 ,2 after zero day, 1 st day, 2nd day ,3rd day and 4th day of the storage period respectively. At zero day, for all samples the initial counts of APC was 5.9x104 +0.6x104 . For control sample and treated samples with 0.5%,1%,1.5%of thyme oil ,the mean counts were 8.2x104 +0.7x104 , 2.1x105 +1.6 x 105 , 5.3x105 +1.2x105 , 1.5x106 +0.6x106 3.7x104 +0.5x104 , 3.2x104 +0.7x104, 4.0x103 +0.6x103, 2.1x103 +1.8x103 & 2.5x104 +0.4x104, 1.9x103 +1.1x103 , 3.6x103 +1.4x103 , 1.6x103 +0.8x103 & 1.8x104 +0.5x104 , 1.4x104 +0.4x104 , 2.9x103 +0.8x103 , 1.4.x103 +1.2x103 cfu/g at1 st day,2nd day,3rdday and4th day respectively. Reduction % of APC were37.28% , 45.76%, 93.22%, 96.44%&57.63%, 96.78%, 93.90% ,97.29%&69.49%, 76.27%,95.08%, 97.63% at 1st day,2nd day,3rdday and4th day respectively. BENHA VETERINARY MEDICAL JOURNAL, VOL. 34, NO.1:132 -151 , MARCH, 2018 BENHA UNIVERSITY FACULTY OF VETERINARY MEDICINE Bacteriological evaluation of minced meat with special reference to effect of thyme essential oil on it 133 At zero day, for all samples, the initial count of Enterobacteriaceae was 7.1x103 +0.6x103. . For control sample and treated samples with0.5%,1%,1.5%of thyme oil ,the mean counts were 7.5x104 +0.7x104 , 8.1x104 +1.1x104 , 9.4x104 +1.5x104 ,3.1x105 +1.2x105&5.7x103 +0.5x103 ,5.3x4x103 , 4.1x103 +0.4x103 ,3.8x103 +1.8x103&4.8x103 +0.4x103 ,4.3x103 +1.1x103 , 3.5x103 +1.4x103,,2.9x103 +0.8x103&4.0x103 +0.5x103 ,3.2x103 +0.4x103 , 2.3x103 +0.8x103 , 1.4.x103 +1.2x103 cfu/g in the 1 st day ,2nd day 3 rdday and 4 th day respectively . Reduction% of Enterobacteriaceae count were 19.72% ,25.35% ,42.25% ,46.48% &32.39%,39.44%,50.80%,59.15%&43.66%,54.93%,67.61%,80.29 at 1st day,2nd day,3rdday and4th day respectively. At zero day, for all samples the initialcountsofcoliformwas6.6x103+0.6x103 For control samples and treated samples with 0.5%,1%,1.5%of thyme oil , the mean counts were 4.2x104 +0.7x104 , 8.9x104 +1.6 x 104 , 1.3x105 +1.2x105 ,2.5x105 +0.6x105 &5.1x103 +0.5x103 ,4.2x103 +0.7x103 ,3.6x103 +0.6x103 , 5.6x102 +1.8x102 &3.5x103 +0.4x103, 2.8x103 +1.1x103 , 2.3x103 +1.4x103 , 6.8x102 +0.8x102 & 2.6x103 +0.5x103, 2.0x103 +0.4x103, 1.5x103 +0.8x103 , 6.4.x102 +1.2x102 cfu/g. at 1 st day,2nd day,3rdday and 4th day respectively. Reduction%ofcoliformcountwere22.73%,36.36%,45.45%,91.52%&32.39%,46.97%,57.58%,89.70%&6 0.61%,69.70%,77.27%,90.30% at 1st day,2nd day,3rdday and 4th day respectively. At zero day, for all samples the initial counts of Staphylococci was 5.1x103 +0.6x103 .For control sample and treated samples with 0.5%,1%,1.5%of thyme oil , the mean counts were 8.2x104 +0.7x104 , 2.1x105 +1.6x105 ,5.3x105 +1.2x105 ,1.5x106 +0.6x106 &3.7x103 +0.5x103 , 3.0x103 +0.7x103 ,2.2x103 +0.6x103 ,6.2x102 +1.8x102&2.4x103 +0.4x103 , 1.8x103 +1.1x103 ,8.6x102 +1.4x102 ,5.8x102 +0.8x102&2.0x103 +0.5x103 , 1.5x103 +0.4x103 , 7.8x102 +0.8x102 , 5.3.x102 +1.2x102 cfu/g in 1 st day, 2nd day 3 rdday and 4 th day respectively. Reduction % of Staphylococci count were 27.45%,41.18%, 56.86% ,87.84% &52.94%, 64.71%, 83.14%, 88.61% & 60.78%, 70.59%, 84.71%, 89.61%, at 1st day, 2 nd day , 3 rdday and 4th day respectively . There was a significant antimicrobial effect of different concentrations of thyme oil on bacteriological state of minced beef. |
