As a college student, every penny counts, but so does my health, right? I’m not a rich mom who can spend all her money on the fancy, organic, and pricey produce at Whole Foods. I need to make every single vegetable from Aldi, Lidl, Trader Joe’s, and any other discount grocery store last.

I need to know how to properly store leftovers, what foods should and shouldn’t be kept frozen, the best containers for storing leftovers, and how I can repurpose them into my next meal. I need to make the most of my groceries so I don't waste a dime.

How to properly store leftovers

With a little bit of research and some help from a professional, Jeff Swada, Director of Michigan State University’s Undergraduate Food Science Program, we compiled a guide for helping you make those groceries last a few extra days.

Photo by Vanessa Loring on Pexels

It’s important to keep food out of the “danger zone,” the temperature range where bacteria can grow rapidly between 40 degrees and 140 degrees F. “Before you store foods, you need to make sure that food has not stayed out at room temperature for more than two hours,” Swada said, “If it stays out too long, bacteria can form before you refrigerate.”

It’s important to cool your food rapidly once you’re finished cooking, so you can get your meal out of the danger zone to prevent bacteria growth. The United States Department of Agriculture (USDA) suggests dividing large amounts of food into smaller, shallow containers.

Swada also notes that you want to make sure your containers are not overfull, “typically no more than 2 inches thick.” If you overfill containers, its contents will remain in the danger zone for too long before cooling in the refrigerator. This will lead to rapid bacterial growth causing food to spoil quickly.

Leftovers can be kept in the refrigerator for three to four days or in the freezer for three to four months. After that, frozen leftovers start to lose moisture and flavor, according to the USDA. Every penny counts, but so does good food. No one wants five month old soup lacking all its original flavor.

The best leftover containers

When asked about the best leftover container for preserving food, making it last and preventing bacteria growth, Swada said the best containers have tight fitting lids to minimize moisture loss or gain to prevent freezer burn. The USDA recommends wrapping leftovers well in airtight packaging or sealing them in storage containers to keep bacteria out, retain moisture, and prevent leftovers from picking up odors from other foods.

Photo by Kate Trifo on Unsplash

The minimization of odor transfer is especially important when freezing leftovers. You know how your frozen waffles sometimes start smelling and tasting like the chili you made the other night? Personally, I prefer blueberry waffles, not chili waffles.

Refrigerate versus freeze leftovers

While most foods can be frozen, some can suffer from “chill injury,” and don’t do well in temperatures near or below freezing. This explains why bananas turn black when you put them in the refrigerator or freezer. Swada recommends pre-treatments like lemon juice to prevent browning, or sugar or salt to help with crystal formation and prevent texture loss.

Both the refrigerator and freezer slow down microbial and biochemical reactions, which explains why my grandparents have a chest size freezer stuffed to the brim full of every leftover meal my grandmother has ever made (not kidding, I think they eat Thanksgiving dinner until the New Year).

Regardless, you want your food to be “clean” before refrigerating or freezing. This means cooked to high temperatures to kill bacteria and chilled quickly to prevent regrowth. Swada said if your food is contaminated before freezing, thawing your meal could wake up those microbes and make you sick. If you let food sit out for hours before refrigerating, it could already have toxins. Refrigeration and freezing slow down growth, but do not prevent growth or toxin survival.

Nuts, berries, meat, and baked goods all do well in the freezer. Other foods however, like avocados, will completely lose their texture. If you prepped them, this makes them great for smoothies, but not so great for snacking.

TLDR: avoid the danger zone, keep your foods clean and stored correctly, and prevent yourself from wasting money on groceries. Then, forward this guide to my roommates, so they stop throwing out half of their groceries every two weeks after over-ordering CAVA and forgetting about the meals they made for dinner before the weekend.

How to repurpose leftovers for tonight’s dinner

Photo by Ello on Unsplash

Every once in while, you are possessed by the food waste demon and leave perfectly good carrots at the back of your fridge. It’s okay, we’ve all been there. But, those carrots don’t have to head straight to the trash can. Instead, you can repurpose them and try your hand at kitchen thrifting. I talked with Melanie Hackman, pastry chef at aioli, a bakery in West Palm Beach, Florida, Mei Li, one half of the popular food waste cooking account @foodwastefeast, and Shiva Reddy, an Australian chef with a passion for reducing food waste.

Stale bread is the new wonder bread

Hackman explained that she regularly uses leftover bread in her kitchen. Hackman gave me a rundown of her daily uses of unused bread and pastries. For day-old pastries, make a tasty bread pudding, flavored with either caramel or blackberries. Day-old bread can be soaked in liquid for meatballs, added to stuffing, or made into croutons or breadcrumbs. With day-old croissants, Hackman makes a twice-baked almond croissant or a breakfast sandwich the next morning. “If we have any loaves of bread that may be in surplus they get delivered to neighboring soup kitchens,” Hackman noted. If you don’t see yourself using your leftover bread, please consider offering the food to your local soup kitchen.

Soup stock from food scraps

“Fresh food waste can be used to make stock… [and fruit] peels can make infusions,” Reddy told me. Take your vegetable shavings and leftovers and include them in any soup stock recipe. Additionally, since soup stocks often ask for the bones from chicken, beef, or pork, you don’t need to throw out that rotisserie chicken carcass. It is essential to making a great soup stock, especially if you're looking for something favorable to use with several other leftover ingredients.

Kitchen sink meals

My grandma used to throw just about every leftover in the fridge into a pasta sauce, serving the concoction for Sunday dinner. This is essentially the idea of a kitchen sink meal, although you can make some more elegant recipes that don’t give you a mystery flavor with every bite. Consider using leftover chicken for a quick stew, and steak or pork for a nice salad or barbecue, or try throwing all your veggies that are about to turn into a frittata. However, the smartest way to approach the kitchen sink meal is through a kitchen sink soup. This recipe allows you to use all the odds and ends left behind from other meals. Want to use that leftover garlic, celery, onion, carrot, green beans, rice, leftover broth, spinach, and ham? Throw it all in your crock pot for a trip to flavor town.

Still feeling stuck?

Sisters Li and Irene of @foodwastefeast on Instagram have a website dedicated to salvaging foods that would otherwise go to waste. Not only do they dedicate time to explaining how to avoid waste in the kitchen, they provide detailed “Hero Recipes” for those moments when you open your vegetable drawer for the first time in a week. They also have a cookbook on pre-order called Perfectly Good Food. “These are my favorite kitchen and pantry stocking suggestions and no-waste strategies, and these Hero Recipes can take a bunch of flexible ingredients, including leftovers,” Li explained. “Liquids in particular are great to save in an ice cube tray and pop in the freezer.” She wants anyone working with food to reconsider leftovers as ingredients rather than waste doomed for the landfill.