I found this in my newspaper (it has a Thursday 'Health' issue) and thought I would share it with you because we had been talking about leaving food out for hours which would make it grow bacteria and whether this is bad for the birds. It doesn't actually talk about food or time limits but about bacteria in general but I think it's applicable nonetheless as it basically says that the current obsession with eliminating bacteria is not only futile but also counterproductive to good health (it mentions the Hygiene Hypothesis that I mentioned before so I am also giving you a link to what that is, specifically).
This is the one about the bacteria war:
https://www.washingtonpost.com/news/spe ... ld-i-care/
This one is what the Hygiene Hypothesis is about:
https://en.wikipedia.org/wiki/Hygiene_hypothesis
And this one explores it a bit:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841828/





