ABSTRACT
Considering the widespread consumption of milk powder by the general population as well as the lack of studies on the toxicity of such industrialized foods, this study evaluated the cytotoxic and genotoxic potential of powdered milk from four reputed companies in the food market of Brazil and other South American countries. Milk samples were evaluated in root meristem cells of Allium cepa L., at concentrations of 0.065 and 0.13 g/mL, for 24 and 48 hours of exposure; and by means of cell viability in culture of cells of normal lineage, via MTT test, for 24 hours, at concentrations of 0.016; 0.032; 0.065 and 0.13g/mL. The concentration 0.13 g/mL was the one suggested for consumption in all milk packages evaluated in this study. In A. cepa, we observed that the milks, at both concentrations and at the two exposure times investigated, reduced the cellular proliferation of root meristems demonstrating a significant cytotoxicity. Furthermore, 0.13g/mL milks at the exposure time of 24h induced an expressive frequency of cellular alterations in the plant tissue, showing to be genotoxic. In the in vitro evaluation, three milks at 0.065 g/mL and all milks at 0.13 g/mL have significantly reduced cell viability, proving to be cytotoxic to the analyzed cell culture. Therefore, under the studied conditions, the powdered milks evaluated caused significant genetic instability to the cells of the test systems used.
Devido o amplo consumo de leite em pó pela população em geral, bem como, a carência de estudos sobre a toxicidade de tais alimentos industrializados, objetivou-se na presente pesquisa avaliar o potencial citotóxico e genotóxico de leites em pó provenientes de quatro empresas de reconhecida atuação no mercado de alimentos brasileiro e de outros países da América do sul. As amostras de leite foram avaliadas em células meristemáticas de raízes de Allium cepa L., nas concentrações 0,065 e 0,13g/mL, por 24 e 48 horas de exposição; e por meio da viabilidade celular em cultura de células de linhagem normal, via teste MTT, por 24 horas, nas concentrações 0,016; 0,032; 0,065 e 0,13g/mL. A concentração 0,13 mL/kg foi a sugerida para consumo em todas embalagens de leites avaliados neste estudo. Em A. cepa, verificou-se que os leites, nas duas concentrações e nos dois tempos de análise considerados, reduziram a proliferação celular dos meristemas de raízes demonstrando citotoxicidade significativa. Ainda, os leites na concentração 0,13g/mL induziram, no tempo de exposição 24h, frequência expressiva de alterações celulares ao tecido vegetal, mostrando-se genotóxicas. Na avaliação in vitro, três leites na concentração 0,065g/mL e todos na concentração 0,13g/mL reduziram significativamente a viabilidade celular mostrando-se citotóxicos a cultura de células analisada. Portanto, nas condições de estudo estabelecidas, os leites em pó avaliados causaram significativa instabilidade genética as células dos sistemas testes utilizados.
Subject(s)
Cell Survival , Dairy Products/toxicity , Food, Preserved , Mutagenicity TestsABSTRACT
In this study, the bacteriological examination of 130 street marketing milk samples and 251 milk product samples revealed that 47 isolates of Staphylococcus aureus were recovered from 130 milk samples with a percentage of 36% and 31 isolates of S.aureus were recovered from 251 milk product samples with a percentage of 12.4%. The pathogenic activity of the isolated S.aureus from milk and milk products were studied including Heamolytic activity, DNase activity and coagulase activity. The results proved that 70 isolates out of 78 tested isolates were Heamolytic and 72 isolates have DNase activity and 60 isolates have coagulase activity. By using latex slide agglutination Test was used for detection of Protein A in isolated S.aureus from milk samples. The results proved that 46 out of 47 isolates contained protein A. Concerning the ice cream samples 11 out of 13 tested isolates contained protein A. and 16 out of 18 tested isolates from Kariesh cheese contained protein A. The results showed that, out of 78 tested isolates 20 isolates were proved to be enterotoxin A producer, 2 isolates were enterotoxin B producer and 5 isolates were enterotoxin C producer by using ELISA