Anna posted this question on Monday. I was intrigued by the question because 70 cents per person per meal isn't a lot of money to feed a large group, even when discounts for purchasing in bulk.
Even though the food budget at work is more than double Anna's, my answer is based on experience. While I buy the bulk of our food supply from Sysco Food Services, I use the markets listed below to purchase food on sale and to take advantage of special deals to save money.
I cook weekly for 160 needy community members, ages 5 to around 90. I have helpers, so one person can do the entree, one the salad, one the bread and donated desserts, one the beverages. The problem is sustaining the budget as our numbers keep growing. I want to serve the best nutrition possible for about $.70 per serving.I commend you for your effort. Purchasing on a limited budget is one of the most challenging situations for a chef.
A budget of 70 cents per meal requires intimate knowledge of the food market in your city. You must developed a keen sense of locating deals, as well as becoming a frugal shopper.
You need to be tuned into local market food prices and be ready to adjust the menu on a moment's notice. Stores like Wal-Mart, local 99 cent stores and other discount stores in town can be a great source of discount food.
Pick up the Wednesday section of the newspaper and search the market ads for weekly specials. When ground beef, beef chuck, pork putt, whole chickens, etc., go on sale, be ready to buy in bulk (as long as you have space in the freezer). I take advantage these products when prices hover around $1 per pound.
Learn how to cook the cheaper, but more flavorful, cuts of meat. Beef chuck and pork shoulder can be turned into dozens of dishes, especially when braised, smoked or slow roasted.
I'd also keep a close eye on the serving size of the main protein source. While it's nice to offer a 5- to 6-ounce portion of meat, a budget of 70 cents per meal makes this a challenge. To avoid smaller portions, focus on casseroles, soups and stews, where the protein can be incorporated into the dish.
Another strategy is to offer a vegetarian entree each week (or so). As long as you watch the amount of eggs and cheese in each recipe, the use of vegetarian dishes can help save the cost of purchasing meat, since it's the costliest element of the menu.
One last idea: Search the community for donations, either of food or money. I worked at a boys home many years ago that received produce, dairy and eggs from a local supermarket.
Each morning I planned the meals for the day based on the food that was donated the day before. While it's a challenge, its situations like this that bring out the best in a cook.