CHEMICAL ANALYSES OF SOME FOOD SAMPLES AND EFFECT OF THEIR HEAVY METALS ON MICRO-ORGANSIMS

Document Type : Original Article

Authors

Agric. Chem. Department, Faculty of Agric., Mansoura University, Mansoura , Egypt

Abstract

Heavy metal is a group of metals has atomic density greater than 5.0 g/cm3, usually associated with pollution and toxicological problems .Six food samples were chosen for this study. These samples are two canned, two frozen and two fresh samples. Rutin chemical analysis was carried out including, moisture, ash, lipid, crude protein and total carbohydrates contents.Elementary analysis was also applied including five elements;Fe , Ni, Co, Cd and  Pb . Results indicated that frozen shrimp contained the highest amount of moisture, protein and ash. Average values of 21.0, 54.80 and 15.50 % was detected, respectively. While, canned luncheon showed to have the highest content of Fe, Pb and cadmium to be 416.3, 2.33 and 6.78 ppm, respectively.
The effect of the above mentioned elements on yeast growth ( Saccharomyces cerevisae) and six bacterial strains, two Grampositive Bacilluscereus&Staphylococcus aureus and four Gram  negativeof pathogenic bacteria,Shigellaflexineri , Enterobactersakazaki,  Salmonella sp.  and Escherichia coli,  and two concentration from every metal was investigated. In the experiments, yeast and six isolates of bacteria has been cultured in petri dishes which supplemented with different concentration of Fe , Ni , Co, Cd and  Pb individual and incubated at  30°C and  37°C/48 h for yeast or bacteria respectively. Yeast and bacterial growth was measured using diameter of inhibition zone. Findings obtained from this study indicated that yeast growth reduced at presence of 1.0mM /L concentration of  3150 ppm and 6300 ppm Fe in comparison with control. Growth of all bacterial isolates were inhibited by Fe . Also Cobalt and Cadmium inhibited the growth of some bacteria while no effect on growth was observed with yeast.

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