In this study, the numbers of bacteria a housefly can carry on its body and transfer to a clean surface
after exposure to a sugar–milk aqueous solution, steak, and potato salad contaminated with a fluorescent gene Escherichia coli
(8 log10 CFU/ml) were determined. In the first series of experiments to quantify bacterial numbers on the flies, about 40–60
flies were transferred into a sterile cage, exposed to the food for 30 min, the flies immobilized and the attached E. coli on each
fly enumerated. Detectable E. coli (>1.7 log10 CFU/fly) were found on 43% (29/67), 53% (23/43),