Cereal products, insects infesting

The excreta of stored product insects are composed primarily of uric acid. However, in some species, the presence of other purines in lesser proportions has been reported. Ammonia is found in the excreta of larvae of Ephestia kuehniella, urea and allantoin in Tenebrio molitor, and both urea and xanthin in larval excreta of C. cephalonica (Bursell, 1967). Uric acid has been used as an indicator of insect infestation in cereals and cereal products since the 1950s (Subrahmanyan et al., 1955 Venkatrao et al., 1957). Subsequently, several methods have been described to determine uric acid levels in infested foodstuffs (Table VII). Most of these methods are modifications of tests originally developed for analysis in clinical samples. Pachla et al. (1987) have reviewed the methods of uric acid determination in foodstuffs and biological fluids. 

Pachla, L.A. and Kissinger, P.T. 1977. Monitoring insect infestation in cereal products—determination of traces of uric acid by high-pressure liquid chromatography. Anal. Chim. Acta 88, 385-387. 

Wehling, R.L. and Wetzel, D.L. 1983. High-performance liquid chromatographic determination of low-level uric acid in grains and cereal products as a measure of insect infestation. J. Chromatogr. 269, 191-197. 

Biology and Habits of the Most Common Insects That Infest Cereal Grains and Their Products... 

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