El- Shishnagui, S., Fathalla, M. (2001). A Bacteriological Study of some Seafood in Alexandria with Special Reference to the Incidence of Vibrio Vulnificus. Journal of High Institute of Public Health, 31(2), 203-216. doi: 10.21608/jhiph.2001.233483
Sawsan M.L. El- Shishnagui; M G. Fathalla. "A Bacteriological Study of some Seafood in Alexandria with Special Reference to the Incidence of Vibrio Vulnificus". Journal of High Institute of Public Health, 31, 2, 2001, 203-216. doi: 10.21608/jhiph.2001.233483
El- Shishnagui, S., Fathalla, M. (2001). 'A Bacteriological Study of some Seafood in Alexandria with Special Reference to the Incidence of Vibrio Vulnificus', Journal of High Institute of Public Health, 31(2), pp. 203-216. doi: 10.21608/jhiph.2001.233483
El- Shishnagui, S., Fathalla, M. A Bacteriological Study of some Seafood in Alexandria with Special Reference to the Incidence of Vibrio Vulnificus. Journal of High Institute of Public Health, 2001; 31(2): 203-216. doi: 10.21608/jhiph.2001.233483
A Bacteriological Study of some Seafood in Alexandria with Special Reference to the Incidence of Vibrio Vulnificus
1Department of Food Hygiene, Animal Health Research Institute, Agriculture Research Center, Alexandria, Egypt
2Department of Microbiology, Central Laboratory of Food and Feed, Agriculture Research Center, Alexandria, Egypt
Abstract
A total of 180 samples of seawater fish [60 samples], molluscs [64 samples] and crustaceans [56 samples] were collected randomly and aseptically in a fresh condition, from different retail fish markets in Alexandria governorate. The collection and examination period extended from March 1999 to February 2000, where the four seasons of the year were represented. Fecal coliforms, fecal streptococci and Vibrio vulnificus (V.vulnificus) were enumerated using the multiple tube most probable number [MPN] technique and total aerobic mesophilic count and total halophiles were enumerated by the pour plate method. Fecal coliforms and fecal streptococci were isolated at high rates along the examination period. All seafood samples, in summer and autumn were positive for fecal coliforms and most of samples for fecal streptococci. The level [mean log MPN/ 100g] of both indicators varied according to season higher counts of fecal coliforms were observed in summer months. [4.82, 5.25 and 4.04 for fish, molluscs and crustaceans respectively], and also of fecal streptococci [4.51, 5.51, and 3.58 for fish, molluscs and crustaceans respectively]. level of fecal coliforms and fecal streptococci varied also according to the type of seafood where molluscs exhibited relatively higher counts than fish and crustaceans. The fecal coliforms to fecal streptococci ratios in the examined seafood samples along the different seasons, ranged from 0.8 to 1.36, which indicated mixed human and animal fecal pollution of such samples. The mean log c.f.u/g of total aerobic and total halophilic counts in fish, molluscs and crustaceans were higher in summer than in the other seasons. Fish exhibited relatively higher counts than molluscs and crustacean samples. 26.6% of fish, 31.2 of molluscs and 14.2% of crustacean samples were positive for V. vulnificus in spring season, with means of 2.03, 2.01 and 3.08 log MPN/100 g while the corresponding figures in summer where 40%, 56.2% and 35.7% with means of 4.24, 5 and 3.9 log MPN/ 100 g. In autumn the figures were 20%, 25% and 14.2% with means of 1.87, 2.57 and 3.7 log MPN/ 100 g. While in winter all seafood samples had counts less than 3 organisms/ 100 g. (which were considered negative). There was a statistically significant difference between V. vulnificus densities in the different seasons at 0.05 level of significance. Higher mean counts were observed in summer than in the other seasons for fish, molluscs and crustaceans [4.24, 5.04 and 3.9 respectively] whereas the organism was completely absent in winter. The relationship between V. vulnificus and fecal indicators' counts revealed a non-significant correlation between V. vulnificus and fecal coliforms in fish and molluscs however, the correlation was moderate in crustaceans. The correlations between V.vulnificus and fecal streptococci were also non-significant in fish and crustaceans and negative in molluscs. Mean total aerobic counts were higher than that of V. vulnificus in all the examined seafood samples but the correlation between such counts was moderate in fish and weak in molluscs samples. However the correlation was very weak and negative in case of crustaceans. Mean total halophilic counts [c.f.u/ g] were also higher than that of V. vulnificus and the correlations between such counts were moderate in all the examined seafood samples.
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