Use of activated clays for prevention of infestation in stored cereal grains

Abstract

Forty-six samples of clay from different locations in Pakistan were collected and ‎chemically analysed to find out their mineral constituents. The clays containing high ‎percentage of Kaolin and high insecticidal properties, were selected for activation, ‎and a method was standardized for activation of the clays.‎

The optimum Level for mixing activated clay, with wheat grains, to obtain Maximum ‎insecticidal effects, was determined, The effectiveness of the clays in checking ‎insect activity depended on percentage of the activated clays used and the storage ‎conditions of wheat. The clays with high Alumina contents (more than 35%), when ‎activated showed high insecticidal properties. Large scale insecticidal activity trials ‎of the clays were conducted by Pakistan Agricultural Storage and Service ‎corporation Limited and the clays were found to possess high insecticidal activity.‎

Rat feed trials were conducted to assess possible toxic effects of these clays when ‎mixed with wheat and milled into flour for human consumption. It was observed that ‎the rats thrived on the test or the control diet equally well.‎

Aluminium Sulphate (if H2SO4 is used for activation) or Aluminium chloride (if HCl ‎is used for activation) are bye-products of activation process These chemicals are ‎being consumed by textile, paper and other industries. Production of activated clays ‎will help in reducing dependence on import of these chemicals.‎