Most weeks between October and June, I purchase 60# of produce for $10 from one of two local charities in the Tucson/Phoenix area. As much as like I produce, that is more than I can use so I have developed a number of neighbors who are interested in produce. The rest gets sent off to one of the local food banks.
The source of this produce is the produce brokerages in Rio Rico, AZ. The brokers purchase produce from the large growers in Western Mexico and sell to wholesalers and other customers in the western and midwestern states.
Since produce has a very limited shelf life and the brokers are competing with brokers representing other regions, there are a lot of leftovers. In the past, most of the excess produce would be dumped at the Santa Cruz County (AZ) dump. Now, the produce is "rescued" and sent out to the local charities.
The one bad thing about this situation is that I cannot always identify what I will get ahead of time. Last week, we received a lot of tomatillos and poblano peppers and iceburg lettuce. Next week, it may be five different types of tomatoes.
The quality of the produce is pretty decent. I am used to surplus produce with a 70% yield. Most of the time, this produce has a 80-90% yield.
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Since Kroger's was trashed above, I have to mention a couple of things.
In the state of Virginia, a state where I worked in the food service industry for three years, it is very common for waste food to be sold off to hog farmers for feeding. A couple of the places that I worked for participated in that program.
In this area, Kroger's send its surplus to the local food banks. Quite often the local food banks are processing the leftovers from Kroger's and Safeway when I am dropping off produce.
As a general rule, Kroger's does NOT sell second-rate produce. They will sell day-old bread and occasionally give away some meat that has not sold on its expiration date.
One should also remember that a lot of the less attractive produce goes to the canning factory where such fruit and vegetables is welcome.