Some years ago when I lived with my parents the refuse collectors were emptying our bin and a load of maggots fell out of one of the bags and were all over the path. We just left them and half an hour later when I left to go to work they had disappeared. I reckon all the birds had had a feast.
As soon as your wheeliebin has been emptied, scrub it out with a broom & Jeyes Fluid & water solution. Rinse out, turn upside down to drain then stand it in an open place until dry. Always wrap cooked food in newspaper then bag & close the top. Put all rubbish in bin bags to keep the bin clean.
Repeat the cleaning process every month during warmer months, in the winter spray with Jeyes solution at each emptying.