الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The present study reavealed the prevalence of Arcobacterspp. in 200samples of meat, including100 poultry meat (50 thighs and 50 breasts), 50 fresh meat and 50 minced meat that were collected from retail shops throughout Assiut City.
Arcobacterwas recovered from 8 % of fresh chicken breast and could be isolated from chicken thigh in a percentage of 14%. The identified species were A.butzleriwhich could be isolated only from 2 % of chicken breast samples and 4 % of chicken thigh samples;A. cryaerophilus with a percent of 2 % chicken breast samples and 6 % of chicken thigh samples andA. skirrowii which could be isolated from4 % of each chicken breast and chicken thigh samples.
In case of fresh meat samples Arcobacter spp. isolates represented 4 %. The recovered isolates were A. cryaerophiluswith a percentage of 2% and A. skirrowiiin a ratio of 2% also, but A.butzlerifailed to be isolated from fresh meat samples.
Regarding to minced meat samples, Arcobacter spp. were recorded in in 6% of the examined samples. In addition, A.butzleri and A. cryaerophiluswere isolated from the positive samples in incidences of 2 % for each. While, A.skirrowiiwas not detected in the examined minced meat samples.
The biochemically identified A. butzleristrains were subjected to confirmation by using PCR and the results were compatible with the biochemical identification.
In the present study, PCR was carried out for screening of some putative virulence genes in the isolated A. butzleri strains. The obtained data revealed that the detected genes were tlyA and cadF andirgA.
The antibiotic sensitivity test for Arcobacterspp.showed that the
resistance of Arcobacterspp. isolates against Penicillin G and Cephalothin was found to be 100% followed byOxacillin and Sulphamethoxazol(93.7% each), Erythromycin(81.3%) and Ampicillin (75%). Besides, resistance to Nalidixic acid (68.8%), Ciprofloxacin (62.5%), Cefotaxime (50%), Amikacin (37.5%) and Enrofloxacin (31.3%) was evident whereasa low percentage of Arcobacterspp. isolates demonstrated resistance to Doxycycline (18.8%), Gentamicin and Tetracycline (6.3% each).
An experimental study was conducted to investigate the antimicrobial activity of Cinnamon, Rosemary and Thyme EOin growth media and in minced meat (food model).
The investigation revealed that within the tested antimicrobials; the cinnamon essential oil (EO) was the most efficient against tested A.butzleri strain in growth media. The cells were killed by a concentration of 0.5 %. The minimum inhibitory concentration (MIC) of cinnamon EO was 0.25%. Regarding rosemary and thyme EO, MIC was 2 % and 0.5%, respectively. While, the MLC was 4% and 1% for rosemary and thyme EO, respectively.
The essential oil which had the best inhibitory effects against A.butzleri in the laboratory medium and in-vitro study, should be chosen and tested for the food model study (in vivo) by using minced meat which inoculated with adjusted initial inoculum of the pathogen (1 x 107cfu/g) and stored at 4ºC for 24 hr. The obtained results showed that cinnamon EO (0.5 and 1%) has highest inhibitory effect against A.butzleri after the 24hr of storage with reductionrate of (99 and 99.98%), respectively. Thesensory evaluation of minced meat treated with these levels showed that the sensory attributes of treated minced beef samples during cold storage (4ºC) were improved by using different concentrations of cinnamonEO.compared to the control samples during the storage period.
The public health significance of the isolated A.butzleri was discussed and the suggestive measures to protect the consumers were outlined.