Effects of washing pre-treatment on mercury concentration in fish tissue

Assessment of some heavy metal accumulation and nutritional quality of shellfish with reference to human health and cancer risk assessment: a seafood safety approach

This study was conducted to assess the proximate analysis (protein, carbohydrate, lipid, and moisture content) and concentration levels of metals (Zn, Cu, Cd, Pb, and Cr) in the muscles of selected shellfish (Portunus reticulatus, P. segnis, P. sanguinolentus, Scylla olivaceae, Penaeus monodon, and P. indicus) species. The concentration of metals showed significant difference (p > 0.05) among species. The detected concentrations of the analyzed heavy metals were below the daily intake and legal limits set by national and international standards. The THQs and CR index were calculated to evaluate the risk estimation of the metal contamination associated with the human health. The THQ values of all metals were below 1 in all species, indicated that there is no risk of adverse health effect, but the risk of elevated intakes of heavy metals adversely affecting food safety for the studied species. The CR index indicated that Cd and Pb caused the greatest cancer risk. The correlation and multivariate (principle component analysis) among metal concentration and nutritional quality were also evaluated. The carbohydrate and moisture showed the positive correlation (p > 0.05) with metals. The biochemical results of the present work clearly indicate that there was a significant difference in the muscles of shellfish. It was concluded that more effective controls should be focused on Cd and Pb to reduce pollution for quality and seafood safety concern.

Cultivation of Solanum tuberosum in a former mining district for a safe human consumption integrating simulated digestion

BACKGROUND

Potato (Solanum tuberosum) is a global crop and by far the most important non-cereal crop in the world. Therefore, it is necessary to assure its safe consumption. This is especially relevant in the case of its cultivation in abandoned mining areas, where the population tends to return to agriculture. In the present work, the objective is to evaluate the contribution to the diet of nutrients and contaminants of potato grown in soils from the Almadén area (mining district) by studying the intestinal absorption (in vitro) of the tuber, taking into account the preparation methods for its consumption.

RESULTS

The results of contaminant and nutrient contents show that the potato peel retains significantly more elements (mainly in the case of toxic elements) than the flesh. Furthermore, potato (peel and flesh) is a good source of iron.

CONCLUSION

It is recommended to boil potatoes with the peel in order to minimize nutrient loss and, before consumption, peeling them to eliminate possible risks due to contaminants. In addition, to minimize the risk due of mercury and to improve the levels of calcium, magnesium, potassium and sodium, it is recommended to add salt during the boiling process. © 2017 Society of Chemical Industry.

Use of Saccharomyces cerevisiae To Reduce the Bioaccessibility of Mercury from Food

Food is the main pathway of exposure to inorganic mercury [Hg(II)] and methylmercury (CH₃Hg). Intestinal absorption of these mercury species is influenced by their chemical form, the luminal pH, and the composition of the diet. In this regard, strategies have been proposed for reducing mercury absorption using dietary components. This study evaluates the capacity of Saccharomyces cerevisiae to reduce the amount of mercury solubilized after gastrointestinal digestion that is available for intestinal absorption (bioaccessibility). The results show that S. cerevisiae strains reduce mercury bioaccessibility from aqueous solutions of Hg(II) (89 ± 6%) and CH₃Hg (83 ± 4%), and from mushrooms (19-77%), but not from seafood. The formation of mercury-cysteine or mercury-polypeptide complexes in the bioaccessible fraction may contribute to the reduced effect of yeasts on mercury bioaccessibility from seafood. Our study indicates that budding yeasts could be useful for reducing the extent of intestinal absorption of mercury present in water and some food matrices.

The significance of cephalopod beaks in marine ecology studies: Can we use beaks for DNA analyses and mercury contamination assessment?

Cephalopod beaks found in the diet of predators have been a major source of scientific information. In this study, we evaluated the usefulness of DNA and contaminants analysis (total mercury - T-Hg) in cephalopod beaks in order to assess their applicability as tools in marine ecology studies. We concluded that, when applying DNA techniques to cephalopod beaks from Antarctic squid species, when using flesh attached to those beaks, it was possible to obtain DNA and to successfully identify cephalopod species; DNA was not found on the beaks themselves. This study also showed that it is possible to obtain information on T-Hg concentrations in beaks: the T-Hg concentrations found in the beaks were 6 to 46 times lower than in the flesh of the same cephalopod species. More research on the relationships of mercury concentrations in cephalopod beaks (and other tissues), intra- and inter-specifically, are needed in the future.

Reduction of mercury from mackerel fillet using combined solution of cysteine, EDTA, and sodium chloride

An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.

Mercury distribution and lipid oxidation in fish muscle: effects of washing and isoelectric protein precipitation

Nearly all the mercury (Hg) in whole muscle from whitefish (Coregonus clupeaformis) and walleye (Sander vitreus) was present as methyl mercury (MeHg). The Hg content in whole muscle from whitefish and walleye was 0.04-0.09 and 0.14-0.81 ppm, respectively. The myofibril fraction contained approximately three-fourths of the Hg in whitefish and walleye whole muscle. The sarcoplasmic protein fraction (e.g., press juice) was the next most abundant source of Hg. Isolated myosin, triacylglycerols, and cellular membranes contained the least Hg. Protein isolates prepared by pH shifting in the presence of citric acid did not decrease Hg levels. Addition of cysteine during washing decreased the Hg content in washed muscle probably through the interaction of the sulfhydryl group in cysteine with MeHg. Primary and secondary lipid oxidation products were lower during 2 °C storage in isolates prepared by pH shifting compared to those of washed or unwashed mince from whole muscle. This was attributed to removing some of the cellular membranes by pH shifting. Washing the mince accelerated lipid peroxide formation but decreased secondary lipid oxidation products compared to that of the unwashed mince. This suggested that there was a lipid hydroperoxide generating system that was active upon dilution of aqueous antioxidants and pro-oxidants.