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Ask the Expert: What do we need to know about food safety?

May 10, 2023

As food prices continue to increase, people are looking for ways to stretch the expiration dates on their food and purchase items that are on the manager’s special. But what are the best practices when it comes to food safety and preserving food for longer?

Graham McKeen, assistant university director of public and environmental health at Indiana University Graham McKeen, assistant university director of public and environmental health at Indiana University We asked Graham McKeen, assistant university director of public and environmental health at Indiana University, some questions regarding food safety and preservation and what people can do to ensure they consume safely handled food.

Question: Is it safe to buy meat or other products at the grocery store near the expiration date, such as those on manager’s special?

Answer: Yes, it’s safe. There’s not a lot of stipulation or information in our food codes about how long you can use the protein before you don’t want to. There are so many competing organisms in raw meat that they cancel each other out.

Also, before pathogenic microorganisms are present, you’re generally going to have spoilage microorganisms, so you’ll see discoloration, mold, yeast or bacterial growth. But generally, it is safe to have products near the expiration date as there is no real standardization federally in terms of expiration dates. They’re not based on safety per se; they’re more based on peak quality, freshness, taste or texture. But many of them are just there to help you use or dispose of that product and then buy a new one.

Q: Are certain products safer to eat past their expiration date than others?

A: Nonperishable food items and low-acid canned foods will be safer for longer. As long as the canned food is in good condition, there’s no rust, dents or swelling, those can often be good, and are, for years at a minimum.

Potentially hazardous foods are time- and temperature-controlled foods. Those are the ones we hone in on, and those would require refrigeration to avoid spoilage. It’s basic and technical. It’s based on the water activity of that food but within ranges supporting bacterial growth. So you’re mainly talking about raw proteins, cooked vegetables, cooked meats, shellfish, seafood, dairy products, tofu products, soy products and cheeses.

Another critical thing about raw proteins is that if they’ve been appropriately held at proper temperatures before they are cooked, they should be safe. If you store raw proteins at an improper temperature before cooking, you could grow spore-forming bacteria or toxins that average cooking temperatures might not kill. An example is hepatitis A, which has a heat inactivation of 185 degrees, where we only cook things such as steaks or hamburgers at 145 or 155 or chicken at 165.

It’s essential to ensure that items are correctly stored and managed properly before cooking them, and then also ensure that people cooking the food themselves are not sick and may shed viruses or pathogenic bacteria.

Q: What are the big no-nos regarding food storage and food safety?

A: Do not keep chemicals around food; segregate and partition any substances away. Store food at the proper temperatures. Anything in the fridge should be at 41 degrees or below, and be stored, protected or covered. Keep ready-to-eat food above raw products in storage.

Time is a big one. For example, if you open a commercially made tuna salad or make a tuna salad in your house, you have seven days to use that product before throwing it away or stopping eating it.

The temperature danger zone in food safety is 41 degrees to 135 degrees. It’s best to avoid having food between those numbers. When cooking or cooling, we want to get through that range quickly.

Food in the fridge should be at 41 or below. It doesn’t mean that bacterial growth cannot occur. Some bacteria, specifically listeria or botulism, can grow at refrigeration temperatures. They grow very slowly; it takes about nine days to grow enough to make you sick.

Q: Any food preservation tips?

A: Keep food at the right temperature. Keeping it covered is going to help with preservation. Other things that can be done to make foods safer includes curing them, like cured meats. Adding salt to that meat locks up the available moisture and makes it more shelf stable. You can also acidify things or ferment foods to help extend shelf life.

For example, many sushi chefs add vinegar to their rice to acidify it so they can work with it at room temperature safely. But in terms of preservation, ensuring it’s being held within the proper temperature ranges and for the appropriate time is the safest bet.

But if ever in doubt, throw it out. That is the main takeaway message. When talking about expiration dates, people often believe that when food is labeled “sell by” or “best before,” that it is based on food safety, but it is not.

“Use by” is the closest terminology based on safety and something you might not want to use after that time. But often, it is not like those foods become toxic at midnight on the expiration day. Much of that is based on quality or freshness and not safety.


University Communications and Marketing

Jocelyn Aguilar

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