Twenty-five samples of canned fish (tuna and mackerel), frozen fish (mackerel and mazelli) as well as smoked fish (herring); five samples of each were randomly collected from different localities of Alexandria city. Collected samples were subjected to biogenic amine examination. Histamine and Tyramine were determined by HPLC. The highest average value (mg/100g) for histamine was 6.94 (canned tuna) and the lowest was 0.76 (Frozen Mazelli), the respective values for Tyramine were 1.63 (canned tuna) and 0.06 (frozen mazelli) mg/100g. For improvement the quality of raw fish (fresh sardine, 10 kg) during preparation the fresh sardine prior chilling or freezing was dipped into crude potato extract (as protease inhibitor) to reduce biogenic amines production. In order to test the effect of heat treatment on the concentration of the biogenic amines in fish (Frozen mackerel and sardine) were subjected to oven baking at 1506 C for 20 min. This showed high reduction in the percentage of biogenic amine production due to heat treatment. The public health significance of the biogenic amines as well as the suggested measures for improving the quality of produced products has been discussed

Beef longissimus dorsi steaks were treated with 10, 25, and 50-kGy gamma irradiation and weekly examined during refrigeration storage at 5ºC to evaluate the changes in their organoleptic, bacteriological, chemical and nutritional quality characteristics as well as deterioration criteria. The signs of spoilage became apparent after 17 days of refrigeration storage in control untreated samples compared with 52 days for 10 kGy treated samples; however, samples treated with 25 or 50 kGy remained without signs of spoilage until the end of storage period (4 months). A characteristic burnt flavor was distinguished in irradiated beef samples, which was intensified with high irradiation dose, but decreased during storage. High doses of irradiation especially 50 kGy resulted in a brownish color of meat surface. Moreover, gamma irradiation resulted in high thiobarbituric acid values after treatments and during storage due to lipid oxidation. Thiamin content of beef was severely reduced and the reduction was dependant on the irradiation dose. Riboflavin was also affected by irradiation, but it was much stable than thiamin. The proximate chemical composition of beef was slightly affected by irradiation.