الفهرس 
Chapter I : IntroductionOnly 14 pages are availabe for public view
 |  | from | 91 |  |  |
| | | from | 91 | | |
Abstract
A total of 75 samples of canned fishes represented by canned mackerel, sardine and tuna (25 of each) were collected from different supermarkets in Kalyobia governorate to determine their chemical and bacteriological aspects.
The chemical examination declared that the mean values of pH, TVN and TBA were 6.58 ± 0.04, 13.96 ± 0.78 and 0.15 ± 0.01 mg % for canned mackerel, 6.64 ± 0.03, 12.70 ± 0.66 and 0.11 ± 0.01 mg % for canned sardine and 6.49 ± 0.03, 8.82 ± 0.49 and 0.08 ± 0.01 mg % for canned tuna, respectively. Significant differences (P < 0.05) appeared between the examined samples of canned mackerel, sardine and tuna as a result of their pH, TVN and TBA values.
Bacteriological examination indicated that the mean values of the examined samples of canned mackerel, sardine and tuna were 3.21 x 103 ± 1.42 x 103, 1.35 x 103 ± 0.96 x 103 & 3.11 x 102 ± 1.54 x 102 / g for total anaerobic counts and 1.19 x 103 ± 0.60 x 103, 4.24 x 102 ± 1.47 x 102 & 1.43 x 102 ± 0.82 x 102 / g for total C. perfringens counts, respectively. Moreover, C. perfringens was detected in 32%, 20% and 12% of the examined canned mackerel, sardine and tuna samples, respectively. However, C. bifermentans, C. butyricum, C. putrefaciens, C. sporogenes, C. sordelli and C. tertium were isolated from such examined samples of canned fishes at different percentages.
On the other hand, the average counts of total aerobic spore formers were 2.88 x 102 ± 1.17 x 102, 1.75 x 102 ± 1.10 x 102 and 7.00 x 10 ± 2.64 x 10 / g of the examined samples of canned mackerel, sardine and tuna with isolation rates of 24%, 16% and 12%, respectively. Furthermore, B. cereus, B. circulans, B. coagulans, B. licheniformis, B. macerans, B. megatherium, B. stearothermophilus and B. subtilis were recovered from the examined canned fish with varying percentages.
The differences between the examined samples of canned mackerel sardine and tuna as a result of total anaerobic, total C. perfringens and total aerobic spore formers counts were significant (P < 0.05) as indicated by application of ANOVA test.
Accordingly, the canned tuna samples had the best keeping quality as indicated by their bacteriological and chemical profiles followed by canned sardine and mackerel.
The isolated bacteria and the possible sources of contamination of canned fishes with such organisms as well as some recommendations to improve the bacteriological and chemical quality of these food items were discussed.