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Abstract
Summary
1. Bacteriological Quality of Broilers’ Carcases:
The present investigation was designed to determine the bacterial quality of 150 raw (pre-and post-thawed) and cooked broilers’ carcases during their preparation in Assiut and El-Azhar universities restaurants.
Regarding pre-thawed broilers’ carcases surfaces of Assiut University Restaurant, the mean values of aerobic plate, psychrotrophs, Enterobacteriaceae, coliform and faecal coliform counts were 2.37 0.56 x 106, 2.29 0.39 x 105, 5.88 1.29 x 10, 4.26 0.96 x 102 and 2.68 0.85 x 102/cm2, respectively whereas the corresponding values for those of El-Azhar University Restaurant were 7.83 1.87 x 105, 2.10 0.41 x 105, 2.30 0.57 x 10, 2.96 0.63 x 102 and 5.10 1.10 x 10/cm2, respectively.
Post-thawed broilers’ carcases surfaces showed the presence of the above mentioned bacterial populations where their mean values in Assiut University Restaurant were 1.53 0.36 x 106, 2.16 0.31 x 105, 4.50 1.00 x 10, 5.12 0.85 x 102 and 2.83 0.56 x 102/cm2, respectively while those of El-Azhar University Restaurant were 5.91 0.91 x 105, 11.40 3.27 x 105, 3.10 0.47 x 10, 3.28 0.82 x 102 and 1.70 0.28 x 10/cm2, respectively.
As for cooked broilers’ carcases, the mean values of the determined bacterial population mentioned before for raw broilers’ carcases were 5.50 1.54 x 105, 6.40 2.15 x 104, 6.72 1.09 x 10, 1.30 0.19 x 10 and 1.30 0.19 x 10/g in Assiut University Restaurant respectively whereas those of El-Azhar University Restaurant were 2.59 0.35 x 105, 2.65 1.29 x 104, 4.96 0.89 x 10, 0.66 0.08 x 10 and 0.56 0.07 x 10/g, respectively.
The level of contamination of pre, post-thawed and cooked broilers’ carcases with E. coli varied from 3 - 10 in 8 and 8%, 20 and 16%, and 8 and 16% in Assiut and El-Azhar universities restaurants, respectively. On the other hand, all the examined raw and cooked broilers’ carcases in both restaurants showed non detectable level of Staph aureus ( 100/cm2 or g).
Neck and vent skin of raw (pre-and post-thawed) broilers’ carcases as well as breast muscle of cooked broilers’ carcases of both Assiut and El-Azhar universities restaurants revealed the presence of Enterobacteriaceae, Listeria spp., Staphylococci and Yersinia enterocolitica in variant percentages. Neither Campylobacter nor salmonellae could be recovered from any of the examined broilers’ carcases.
Members of Enterobacteriaceae recovered from the examined broilers’ carcases in variant percentages were Arizona spp., Citrobacter freundii, Edwardsiella tarda, Enterobacter aerogenes, E. coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, P. rettgeri, P. vulgaris, Providencia alcalifaciens, Serratia marcescens and Shigella flexneri. On the other hand, the identified Listeria spp. were L. innocua, L. monocytogenes and L. welshimeri. Furthermore, Staph aureus was the most prevalent followed by Staph epidermidis.
However, 19 E. coli isolates were recovered from the examined raw and cooked broilers’ carcases which were serogrouped into: O26 : K60 (2), O55 : K59 (2), O111 : K58 (1), O119 : K69 (2), O126 : K71 (3), O128 : K67 (3), O142 : K86 (2) and untypable E. coli (4).
2. Bacteriological Quality of Meat Contact Surfaces and
Water Used for Preparation of Broilers’ Carcases:
Workers’ hands and knives used for preparation of broilers’ carcases in Assiut and El-Azhar universities restaurants were found contaminated with various levels and types of microorganisms. The mean values of aerobic plate, psychrotrophs, Enterobacteriaceae, coliforms and faecal coliforms of the examined workers’ hands in these restaurants were 19.66 7.54 x 105 and 23.38 8.91 x 105, 35.10 8.66 x 104 and 4.59 1.19 x 105, 6.22 2.08 x 10 and 4.59 1.19 x 10, 8.47 1.32 x 102 and 3.88 1.22 x 102, and 4.611.74x 102 and 1.33 1.08 x 102/hand; respectively. The corresponding values for the examined knives were 1.43 0.69 x 106 and 4.26 1.41 x 105, 3.82 1.14 x 105 and 2.44 1.17 x 105, 6.64 3.04 x 10 and 4.48 0.68 x 10, 7.59 2.19 x 102 and 2.53 0.66 x 102, and 3.272.11x102 and 7.38 5.41 x 10/knife, respectively.
Various bacterial isolates were recovered from workers’ hands and knives in Assiut and El-Azhar universities restaurants including Enterobacteriaceae (Arizona spp., Citrobacter freundii, Edwardsiella tarda, Enterobacter aerogenes, E. coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, P. rettgeri, P. vulgaris, Providencia alcalifaciens, Serratia marcescens and Shigella flexneri), Listeria spp. (L. innocua and L. monocytogenes), and Staphylococci (Staph. aureus and Staph epidermidis) in variant percentages.
Only three workers’ hands in both restaurants were contaminated with E. coli with a level varied from 3 - 10/hand. The identified serogroups were O111 : K58 , O126 : K71 and O142 : K86 (one each).
Concerning water used for thawing of broilers’ carcases in Assiut and El-Azhar universities restaurants, the mean values of aerobic plate, psychrotrophs, Enterobacteriaceae, coliforms and faecal coliforms counts were 27.53 16.03 x 105 and 4.700.13 x 105, 5.18 1.70 x 105 and 1.41 0.43 x 105, 3.20 1.02 x 10 and 2.96 1.00 x 10, 1.19 0.44 x 102 and 2.89 2.04 x 102, and 8.944.93 x 10 and 4.97 4.01 x 10/ml water before immersion of broilers’ carcases. On the other hand, the corresponding values of the above bacterial population for water after immersion of broilers’ carcases in both restaurants were 74.60 8.83 x 105 and 4.39 1.40 x 106, 5.68 0.79 x 105 and 4.32 1.09 x 105, 1.10 0.39 x 102 and 3.04 0.81 x 10, 8.44 1.57 x 102 and 5.88 2.09 x 102, and 4.04 1.75 x 102 and 5.94 1.98 x 10/ml, respectively.
Five E. coli serogroups were recovered from water of Assiut University Restaurant which were identified as O26 : K60 (1), O119 : K69 (1), O128 : K67 (2) and one untypable strain. However, the level of contamination varied from 3 to 3.6 with a mean values of 3.36 0.15/ml water after immersion of broilers’ carcases.
3. Decontamination of Broilers’ Carcases by Organic Acids:
The bacterial load of broilers’ carcases surfaces dipped in 2% lactic acid was greatly reduced where the reduction rate in the aerobic plate, psychrotrophs, Enterobacteriaceae, coliforms and faecal coliform count reached 99.12, 100, 100, 100 and 100%, respectively.
The bactericidal efficacy of acetic and lactic acids against 16 tested bacterial isolates showed that their minimum inhibitory concentrations (MICs) varied from 0.1 to 8.7% and from 0.4 to 7.7%, respectively whereas their minimum lethal concentrations varied from 3.1 to 25% and from 3.1 to 25%, respectively.
4. Bactericidal Efficacy of Some Disinfectants:
Disinfection of workers’ hands and knives with 1% TH4+ caused reduction in their bacterial load which reached 99.99, 99.99, 100, 100 and 100% for aerobic plate, psychrotrophs, Enterobacteriaceae, coliforms and faecal coliform, respectively.
On the other hand, the minimum inhibitory concentrations (MICs) of Dialox and TH4+ against 16 tested bacterial isolates varied from 0.12 to 0.92% and from 0.11 to 0.8%, respectively whereas the minimum lethal concentrations (MLCs) varied from 0.3 to 1% for the two used disinfectants.
However, the public health importance of the recovered microorganisms was discussed and the suggestive measures for controlling bacterial contamination during preparation of broilers’ carcases in student food service establishments were outlined.