الفهرس 
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Abstract
SUMMARY
For a balanced diet, fish and fish products are essential because they are low in saturated fat ,high in proteins ,free amino acids and high in omega-3 fatty acids, which have been demonstrated to have significant health advantages. This study investigated fresh fish and its products for biogenic amines (histamine, cadaverine , putrescine and tyramine) .This study has been conducted on over 120 random samples of fish products from different fish markets in Shibin El kom ,Menoufia governorate, Egypt, which include fresh fish (lates niloticus ), canned tuna, smoked herring and salted sardine. The findings showed that the average of histamine levels in fresh fish(lates niloticus) , canned tuna , smoked herring and salted sardine were10.74 ± 0.59 , 15.08 ± 0.76 , 17.93 ± 0.81and 26.12 ± 0.89 mg %, respectively. Egypt’s Organization for Standardization (2010) defined the highest residue limit of histamine in fish was not more than 20 mg/100g. Therefore, the number of the unaccepted samples of fresh fish (lates niloticus) , canned tuna ,smoked herring and salted sardine were 4 ,7 , 9 and 14 % ,respectively.
Putrescine concentration ranged from 1.0 to 21.9, with fresh fish having an average of 7.61± 0.49 mg%, 1.7 to 26.4, with canned tuna having an average of 11.13 ±0.57 mg%, 2.1 to 30.2, with smoked herring having an average of 14.35 ±0.64 mg%, and 2.8 to 39.5, with salted sardine having an average of 19.59± 0.81 mg%. Fresh fish, canned tuna, smoked herring, and salted sardine really had 2, 5, 7, and 11 unaccepted samples, respectively, according to EOS (2010) based on their putrescine contents .
On the other hand, the samples of fresh fish (lates niloticus), canned tuna, smoked herring, and salted sardine had respective mean cadaverine concentrations of 5.96± 0.43, 10.22± 0.49, 12.41± 0.58, and 16.85± 0.62 mg. 3.3%, 13.3%, 16.7%, and 26.7%, respectively, of the analysed samples of fresh fish, canned tuna, smoked herring, and salted sardine were unacceptable samples.
Tyramine concentration was from 0.4 to 3.7 with a mean value 2.05± 0.10 mg% for fresh fish, 0.9 to 15.4 with a mean value 6.37± 0.19 mg% for canned tuna ,1.1 to 21.3 with a mean value 7.90± 0.24 mg% for smoked herring, and 1.4 to 23.9 with a mean value 10.44± 0.27 mg% for salted sardine. The unaccepted samples for tyramine residue in smoked herring and salted sardine were 3.3% and 10%, respectively, according to Egyptian Organization for Standardization EOS (2010), while all the tested samples of fresh fish (lates niloticus) and canned tuna were accepted.
Fresh fish fillets (lates niloticus) experimentally inoculated with B. polymyxa culture (2x107) showed a reduction percent in histamine levels from 50 mg/kg to 31.4 mg/kg after eight hours, 19.5 mg/kg after twelve hours, and 12.8 mg/kg after twenty-four hours, with respective percentage reductions of 37.2%, 61.0%, and 74.4% ,respectively .
Mean while reduction percentages were 26.3%, 48.7% and 67.7%,after using B. polymyxa cultur(2x107) decreased the levels of cadaverine experimentally inoculated to fresh fish fillets (lates niloticus) from 30 mg/kg to 22.1 mg/kg after 8 hours, 15.4 mg/kg after 12 hours, and 9.7 mg/kg after 24 hours , respectively.
Finally, the public health significance of biogenic amines and mechanism of their formation in fish products as well as some recommendations to avoid them in such food items were discussed.
References