Heavy metals content of canned tuna fish marketed in Tabriz, Iran

Some heavy metals are dangerous to health and there is rising concern about the quality of foodstuffs in some parts of the world. Fish, particularly Tuna fish, can concentrate huge quantities of several metals from water and they even play a significant role in human nourishment. In this study, the concentrations of mercury and four trace metals in five brands of canned tuna samples purchased within the Tabriz city [Iran] were determined after digestion via the Association of Official Analytical Chemists techniques. A total of 40 samples were collected. Lead and cadmium levels were determined via graphite tube atomic absorption spectrophoto-metry, whereas nickel and tin levels were determined via flame atomic absorption spectrophotometry, and mercury levels were determined via hydride generation atomic absorption spectro-photometry. The ranges obtained for the elements were Pb [0.01-0.242], Ca [0.0-1.05], Ni [0.113-0.589], Sn [0.05-0.9], and Hg [0.1-0.205] mg/kg wet weight. The results showed that tuna fabricated and marketed in Tabriz [Iran] had safe level of heavy metals that were lower than the averages of EC/FAO/WHO levels for these toxic metals

Study on the growth and survival of Escherichia coli O157:H7 during the manufacture and storage of Iranian white cheese in brine

The behaviour of Escherichia coli O157:H7 was studied during the manufacture and storage of Iranian white cheese in brine. Cheese was manufactured using pasteurized cow milk and inoculated with E. coli O157:H7 with inoculum level of 10[3] cfu/ml. Four treatments were designed. Cheeses were made with or without starter culture and kept immersed in 6 or 8% salt brine during ripening and storage. Cheese samples were analysed for E. coli O157:H7 during manufacture and storage period. During cheese manufacture the number of E. coli O157:H7 increased by 10[6] cfu/g, but during ripening and cheese storage the number of organism decreased significantly in the cheese samples made with starter culture [P<0.05]. The results showed an inhibitory effect of starter culture on E. coli O157:H7, but the organism can survive in this kind of cheese for up to 60 days of storage, respecting using starter culture, salt brine concentration and cheese storage time