Analysis and determination of mercury, cadmium and lead in canned tuna fish marketed in Iran

The objective of this study is to determine mercury, cadmium and lead concentrations in 60 canned tuna fish samples produced and distributed in Iran after digestion by the standard methods of the Association of Official Analytical Chemists. Mercury contents in canned tuna fish were determined by cold vapor atomic absorption spectrophotometry while cadmium and lead were determined by graphite furnace atomic absorption spectrophotometry. The metal contents, expressed in μg g-1wet weight for mercury, cadmium and lead varied from 0.010 to 0.401 (average of 0.125), 0.008 to 0.150 (average of 0.050) and 0.021 to 0.301 (average of 0.096), respectively. The values  were comparable and in the range of the literature values. The results of this study indicate that tuna fish produced and marketed in Iran have concentrations well below the standards of FAO/WHO levels of these toxic metals.Key words: Canned tuna fish, heavy metals, mercury, cadmium, lead

Introducing the best cell culture method for primary hepatocyte from orangespotted grouper, Epinephelus coioides

Liver is one of the most important organs in vertebrates that have important roles in detoxifying. This organ was used as a target organ in many physiological and toxicological aspects. The main purpose of the present study was developing appropriate methodology for the primary cultivation of hepatic cells from orange-spotted Grouper, Epinephelus coioides, a subtropical fish species of the family Serranidae. In present study, hepatocytes were isolated from five grouper individuals. Initially, the fish wiped with 70% ethanol. Liver were removed and cut into small pieces with scissors and hepatocytes were disconnected using different enzymatic digestion with collagenase (Type 1 and 4) and trypsin and additional nutrient materials in culturing mediums. Then, cells were cultured for 2 weeks in Lebowitz L-15 under 3 methods: 1. using enzymatic digestion by trypsin, 2. using enzymatic digestion by collagenase (type 1 and 4) and 3. Using nutrients and additives was cultured. Finally, effects of different incubation temperature (20, 25, 28, 30 and 32 degree of Celsius) and Bovine serum content (0, 10 and 20% and 20%+ITS) on cell growth were estimated. According to the results, digestion by collagenase type 4, resulted in more cell colonization and growth in comparison with other methods. At the same method, cells showed fibroblastic morphology. In conclusion, the best culture method for primary hepatocyte from orange-spotted Grouper, Epinephelus coioides, was using ITS+20%FBS under 30 degree of Celsius incubation temperature

Lead and cadmium biosorption from milk by Lactobacillus acidophilus

The food and water contamination with heavy metals is increasing due to the environmental pollutions. Lead and cadmium are the toxic heavy metals for humans that can be found in air, soil, water, and even food. Lactic acid bacteria have the ability to remove and diminish the level of heavy metals. In this study, Lactobacillus acidophilus was used to remove lead and cadmium in milk and the capability of this valuable bacterium in biosorption of these metals low concentrations (µg/L or ppb) in milk was evaluated. First, the variables on lead and cadmium removal by this bacterium have been studied by Plackett–Burman design. Then, the bioremoval process was optimized and the three main factors, the bacterium concentration, contact time, and the initial heavy metal concentration were chosen by using a central composite design. The optimum lead and cadmium bioremoval yield of 80% and 75% were observed, respectively, at 1 × 1012 CFU of L. acidophilus in milk at the 4th day and the initial ion concentration of 100 µg/L. The 3D plots analysis showed the interaction effects on metal biosorption. This study showed that L. acidophilus is a natural effective biosorbent for lead and cadmium removal from milk