sábado, 16 de marzo de 2013
Contaminated water in pesticides could be source of Norovirus entering the supply chain.
Contaminated water used to dilute pesticides could be responsible for viruses entering the fresh food supply chain, claim scientists. The possibility of pesticides being a source of human Norovirus (hNoV) depends on the presence of viruses in the water used to reconstitute the pesticides, the potential of viruses to persist in reconstituted pesticides, and by the number of viruses adhering to the edible parts of the produce.
Farmers use various water sources in production of fresh fruits and vegetables, including well water and surface water such as river or lake water, sources which have been found to harbor hNoV, according to previous research.
In a separate development the European Food Safety Authority (EFSA) has said residue compliance rates remain high in its annual pesticide report.
Fresh produce and Norovirus link. The consumption of fresh produce has been associated with outbreaks of hNoV but it is difficult to identify where in the supply chain the virus first enters production, said a team of researchers. Pesticides are commonly applied in the production of produce just before harvest to optimize product quality and extend shelf life.
To prevent contamination of fresh produce, knowledge of the possible introduction sources of the viruses, such as water, is needed to implement appropriate and efficient preventive measures.
Possible source. The researchers studied the persistence of hNoV GI.4, hNoV GII.4 and murine Norovirus (MNV-1), the only cultivable Norovirus, in eight different pesticides after 0 and two hours. Virus concentrations were determined by reverse transcriptase PCR, and infectivity of MNV-1 was determined by endpoint dilutions followed by maximum likelihood estimations. Chemicals were diluted in a concentration equal to the smallest volume used (200 L/ha) to equal the highest pesticide concentration used in practice. “The application of pesticides may therefore not only be a chemical hazard, but also a microbiological hazard for public health”.
A promising approach to minimize the microbiological health risk of pesticide application, not depending on compliance and awareness of farmers, is the inclusion of antiviral substances into pesticides, concluded the researchers.
EFSA pesticide report. Meanwhile, EFSA’s annual report on pesticides in food, found that more than 97% of samples contained residue levels that fall within permissible limits. MRL exceedance rates of foods imported into the EU, Norway and Iceland were more than five times higher than those of foods originating in these nations - 7.9% compared to 1.5%.
Source: Food QualityNews