Effects of food storage and handling on blow fly (Lucilia sericata) eggs and larvae

Flies can cause food-borne disease by transmitting pathogenic microorganisms into the food we eat or by being ingested themselves ("intestinal myiasis"), usually as eggs or larvae contaminating our food. Because eggs and larvae can easily contaminate our food during harvesting, handling, and preparation, this series of experiments was undertaken to define the food preparation conditions that would be necessary to kill contaminating blow fly eggs and larvae. Replicate samples of Lucilia (= Phaenicia) sericata (Meigen) eggs and larvae were exposed to increasing periods of freezing, refrigeration, baking, boiling, frying, and microwaving. Survivors were counted every 6 to 48 h thereafter, and the exposures that were lethal to 50% (LE50), 90% (LE90), and 99% of our samples (LE99) were calculated. All of the tested food-preparation methods killed most or all of the eggs and larvae when exposed for durations typically associated with food preparation. These results indicate that the common methods of food preparation should adequately kill all L. sericata eggs and larvae that may be associated with raw meat. Freezing and extended refrigeration also killed all eggs and larvae. This supports the belief, hitherto unproven, that contamination of cooked meat products most likely occurs at or after the point of retail-consumer contact.