Studies on insect infestation in chocolates

The ability of stored-product pests including the cigarette beetle, Lasioderma serricorne, the sawtoothed grain beetle, Oryzaephilus surinamensis, the rust-red flour beetle, Tribolium castaneum, and the almond moth, Ephestia cautella, to infest chocolates under packaged and unpackaged conditions was investigated in the laboratory at 25±1 °C and 65±5% r.h. Four types of chocolates were investigated: milk, nut, dried fruit and nut, and wafer chocolates. Adults (beetles only, 20 per replicate) or eggs (30 per replicate) were released on unpackaged and packaged chocolates and infestation levels (number of living adults and larvae) were determined 45 days later. When adult beetles were released on unpackaged chocolates, the degree of infestation varied depending on the species and the type of chocolate. The highest infestation observed in unpackaged chocolate was that of O. surinamensis in wafer chocolate (mean 138.4). When eggs were released on unpackaged chocolates, the most numerous species was E. cautella in dried fruit and nut chocolate (mean population=180.8). With packaged chocolates exposed to adults or eggs, insect infestation was nil or negligible (mean population <6.0). Although infestation levels were low, infestations were found in 50% of treatments over all. Damage to the packaging material along the folds or edges was observed in infested chocolates. The study has shown that milk, nut, dried fruit and nut, and wafer chocolates can support insect infestation and therefore, insect-proof packing of the chocolates and storage under hygienic conditions are important to avoid customers’ complaints.