What do you do with all the expired food inside the supermarket?

Answer your question in one sentence: yes, a lot of food is just thrown away.

In detail, most supermarkets have ways to minimize this loss. Most departments in supermarkets, especially those with goods that have a short shelf life, will only bring in the next batch of goods when they are almost sold out. That's why you sometimes go to the supermarket and find fresh wild salmon sold out. Think about it, would a supermarket really stock a twenty ounce case of fish at eight o'clock at night specifically to sell you eight ounces of fish? The answer has to take into account sales and whether the store is really desperate to keep consumers, but the answer is overwhelmingly no.

Produce - Fruits and vegetables don't have an exact expiration date. I'll go so far as to say that you'll barely find a banana that's just starting to turn brown on the shelves of the produce department. Produce that can't be sold will pretty much be sold elsewhere in the supermarket. The departments that process and sell processed foods will use the produce to make salads, soups, etc. Meat and seafood that is past its sell-by date but still within its eat-by date is handled the same way.

The most natural place for all the unusable produce seems to be as compost. It's an issue we've studied over and over at the supermarket, but there are two main obstacles to implementation.

Storage- Most farms are located far from the city or suburban stores. Because produce spoils so quickly, farms have to come in every day to haul away crops that can be used as compost. Storage in supermarkets is not possible because large quantities of rotting fruit would attract all sorts of pests. Daily transport is difficult to achieve, and is the extra expense of transport and labor and green costs enough to offset the value of the produce? Handling it this way involves far more problems than initially envisioned. Recalls - Unfortunately, fruits and vegetables are often recalled because they are toxic. Produce is usually recalled after it has been on store shelves for a while. If the store uses honeydew melons as compost, the same batch of melons is recalled two days later because of the potential danger of salmonella contamination, when the batch of potentially lethal compost is already on its way to a local farm. I'm neither an expert on foodborne illnesses nor a composting professional, so I'm not sure if this concern is unwarranted, but it sounds scary to me. That's enough to make the offer step aside. Bread- Much of the bread that is no longer fresh is donated to the local food bank and then distributed to local non-profit organizations. A shopping cart of muffins, donuts and bread arrives at the back door each morning, and a truck comes by at 10 a.m. each day to take it away.

Meat and seafood - For the past few months, the staff has been testing frozen meat just past its sell-by date and donating it to local charity kitchens. But again, that was just getting started, and a couple of things happened that knocked the measure back to a paper plan. The most serious issue is and always has been safety. Because frozen products are not 100% safe. What happens to the product at the same time? Traceability is a critical issue until the product reaches the store; but it's economically impossible to maintain traceability from the store to the donation office.

Other food products are sent to food banks. I'm certain that smaller markets will just donate it. In our supermarket, all expired food is packaged up and sent to HQ, where it's distributed equally on the HQ side based on the neighborhoods where our supermarket locations are located. The extra transportation costs may seem like a waste, but I'm guessing that HQ is planning to keep track of all the donations for tax deductions.

I had the pleasure of working at a food bank for a while. They had different rules about the shelf life of food, and I'm guessing it was set by some government agency. For example (and I'm just using this as an analogy, I can't remember the exact dates and numbers), canned beans are still good to eat two years after the date marked on the tin can, while boxed pasta is still good to eat six months after the date marked. When I volunteered at the food bank, most of my work involved sorting through large quantities of canned food, checking the shelf life, and sorting out those that were still edible, and those that were no longer edible.

So in short, as long as it's edible, the food gets donated. If it's not edible, the food gets thrown away. Food is a big issue that is taken very seriously.