Flies thrive on once-weekly trash collection
Over the past couple of years, we have noticed the regular appearance of dozens of maggots in our kitchen. I think this is likely to be the consequence of the move from twice-weekly trash collection to once-weekly collection.
Given the slightest chance green bottle flies (Lucilia sericata) lay eggs in the trash, they hatch in 18 to 24 hours. Once hatched, the larvae feed and grow, moulting three times. In the wake of the third moult, they leave the food source (trash) after four to 12 days and seek somewhere to pupate.
Twice-weekly collections removed them before they could mature enough to leave the trash. Unfortunately, once-weekly collections do not.
However careful you are, it takes only seconds for these flies to get into the trash and lay their eggs. The remedy seems to be an efficient fly killer in the kitchen or to keep all trash outside.