AOAC Official Method 940.34 Insect Eggs in Flour
Sieving Method
First Action 1940
Final Action 1996
Transfer 50 g flour to No. 100 sieve (if >ca 0.1 g residue is obtained,No. 60 or No. 80 sieve should be used to prevent slow filtration after digestion) and sift gently until no more flour passes through. Transfer residue on sieve to 250 mL beaker and wet with 2–3 mL alcohol. Add 30 mL H2SO4 (1 + 19), cover beaker, and heat on steam bath 10 min. Filter through paper on suction funnel, using minimum suction necessary to filter. Keep beaker partially inverted over funnel and rinse with H2O. Turn off suction. Add 15–20 mL ca 0.1M I2 to paper in funnel. Allow 10–15 s for I2 to stain contents. Apply
gentle suction. After I2 passes through filter, wash paper with 25–30 mL 1% H2SO4, followed by several small H2O washes.
Transfer paper to Petri dish and examine at once under 20´ magnification.
Reference: Food Ind. 12, 36(1940).
Revised: March 1997
