As you state in your question, some Las Vegas buffets, including the Orleans, Rio, Aladdin, Circus Circus, and Bellagio, for example, send leftovers that are still in good condition to their employee dining rooms. But with the rigorous health and safety directives surrounding food and restaurants these days, we weren’t surprised to find that others, including, we were informed, Paris, the Mirage, and Caesars, throw out anything that’s perishable. That doesn’t mean the food goes entirely to waste, however: 95% of Strip casinos implement some kind of recycling program, many of which involve the salvaging of waste foodstuffs, which are then used for hog feed.
But some casinos also donate food to the needy of Las Vegas. Sheldon Adelson's wife, Dr. Miriam Adelson, is a leading light in the world of drug-addiction treatment and has opened clinics in her native Israel and here in town. We know that in the past the Dr. Miriam/Sheldon G. Adelson Clinic for Drug Abuse on South Maryland Parkway regularly received cakes, cookies, and pastries from the Venetian, and although we were unable to confirm this definitively, as far as we could ascertain this policy is still in place. (We don't in any way wish to scorn the casino for this act of charity, but we just couldn't help but notice the strange coincidence regarding the initials "M.A." and another lady who purportedly wanted to "let them eat cake.")
We also put in a call to the Catholic Charities of Southern Nevada, one of the groups at the forefront of providing help for Las Vegas' sizable homeless population. Sharon Mann, Director of Community Relations, explained that the casinos have to be very wary of the numerous laws and regulations in place and that previously cooked food represents too great a potential health risk to transport and donate. They do, however, regularly receive fresh fruit and vegetables from many casinos. When Binion's Horseshoe closed, pending its takeoever by Harrah's, Catholic Charities received everything usable from Binion’s kitchens, including fruit, vegetables, and all their frozen goods. Each year they also hold an "April Foods Day" food drive and receive donations of cans and other non-perishables from casino staff all over town.