Israel’s Sephardic Chief Rabbi Shlomo Amar has warned that he will ban the kosher certification of farmers who use pesticides in ways unauthorized by the Health Ministry.

The Chief Rabbinate announced on Monday that it had received data indicating “a grave phenomenon” whereby some farmers of leafy-vegetables use pesticides – for the purpose of preventing insects and worms – at a dosage that is higher than permitted or, alternatively, pesticides that are forbidden by the Health Ministry due to their detrimental health effects.

The rabbinate’s warning came as the Israel Union for Environmental Defense found high levels of 105 different pesticides in fruits and vegetables, a third of which are banned in Europe.

In light of that information, the chief rabbi has warned that local kashrut authorities should only certify those companies that are supervised by the Health Ministry in such a way that ensures they do not use pesticides illegally. The rabbinate instructed that the farmers' credibility be assessed either at Health Ministry laboratories or at laboratories authorized by the ministry.

Furthermore, restaurants and food manufacturers were warned not to purchase unsupervised produce, or risk losing their kosher certificates too.

So far no kosher certifications have been withdrawn.

The rabbinate also called for the immediate, thorough and professional assessment of the phenomenon, so that working procedures could be established between the national kosher department and the Health Ministry, under which the process of applying for supervision will be defined.

Exposure to about 20 of the banned pesticides described in the Israel Union for Environmental Defense report can harm the nervous system or children's cognitive development. Fifteen of them are suspected of being carcinogenic.

That report came only a week after the Central Bureau of Statistics found that Israel has the highest pesticide concentrations in food in the Organization for Economic Cooperation and Development.