I Left It Out Too Long! Can I Still Eat It?

Funny thing, but almost every question we get from our site members is a variation of the same question.  Optimists phrase it positively: “Can I still eat it?”  Pessimists ask, “Do I have to throw it out?”  In either case, it’s a query about food that has been kept too long in the “danger zone” (40°F-140°F), in other words, a perishable food that hasn’t been kept hot enough or cold enough to prevent bacterial growth. No one wants to discard food that cost a lot and/or took a long time to prepare.  So we did some research and asked two food scientists on the Shelf Life Advice Advisory Board to provide specific and general answers to “Is it really spoiled?” questions.

From Marilyn: Sunday evening, she cut up some fresh fruit and put it in a plastic bag to take to work the next day.  She refrigerated it that night and put it on the table Monday morning. But she forgot it, so it sat on the table all day.  Could she then refrigerate it and take it to work the next day? Here’s how Professor Joe Regenstein responded: “That would make me nervous.  If the food had any contamination, the organisms had lots of time to grow. I would chuck it.”  The usual recommendation from food safety experts is to keep cut-up fruit out no longer than 2 hours.

From Alana:  She prepared everything needed to make chicken soup, put it in her slow cooker, and planned to cook it overnight, then refrigerate it in the morning and reheat it for dinner.  However, she forgot to plug it in.  Could she then plug it in the next morning, cook it all day, and have a safe dinner?  Dr. Catherine Cutter sympathized, having suffered a similar mishap with corned beef, a much more expensive item. Her comment: Alana made the right decision in discarding everything in the pot.

Most poultry are contaminated with Salmonella and Campylobacter, bacteria that usually don’t make the bird sick but can make humans sick if the pathogens are not killed by cooking.  These pathogens will grow rapidly on raw chicken at room temperature.  Alana might have defended her pot of uncooked chicken soup this way:  “If I’m going to cook the food, wouldn’t that kill all the bacteria including the ones that grew while it was standing at room temperature?”  Yes, but some bacteria produce toxins (poisons) that are not destroyed even when the food is cooked at a high temperature.  Dr. Catherine Cutter points out, “Staph grow really well on meat and poultry, especially at room temperature.”  She was referring to staphylococcus, which, produce a toxin that, if consumed in contaminated food, is likely to create great abdominal discomfort within a few hours.

From no one: No one asked us this specific question, but, no doubt, many people make this mistake, so we’ll pass the question and answer along to you:  “I left a big pot of chili on the stove unheated for several hours.  Is it still safe to eat?”

Emphatically no, says Dr. Cutter.  “If you have a large or thick amount of food that is not cooled rapidly, you risk the growth of Clostidium perfringens, which causes a diarrheal disease. We see this foodborne illness a lot with improper cooling of thick foods such as casseroles, soups, stew, and chili. You can get a high level of bacteria fast in high-protein foods.  Spores can germinate if the food is not cooled quickly, and the vegetative or actively growing cells are ingested.  Once in the gut, the cells can produce a toxin that causes diarrhea.” Dr. Cutter recommends putting these thick foods into smaller containers and not overcrowding the fridge in order to help the food cool quickly. 

Most people know that keeping perishable food at room temperature is a bad idea.  They may not know that most foods contain at least small amounts of bacteria. Refrigeration slows the growth of most bacteria.  Freezing stops their growth completely but doesn’t kill them.  When the food is defrosted, they’ll continue to grow. Only cooking to a high enough temperature kills the bacteria. However, even cooking food may not kill the spores of some bacteria or some bacterial toxins.

Bacteria are not the only cause of food-borne illness, but they are the main one.  Bacteria multiply very quickly, so the time limit for keeping food at room temperature that’s recommended by food safety experts is 2 hours if the air temperature is about 72°F and one hour if the environment is 90°F or above.  “That’s silly,” some people respond.  “It can’t be that all foods become contaminated at exactly the same time.”  Good point.  However, the 2-hour rule is a protective, conservative guideline that is easy to remember.  (No sense overwhelming one’s memory with a different time period for each type of food, wouldn’t you agree?)

But suppose company is coming in 10 minutes, and you really want to serve your casserole that’s been on the counter for hours.  How can you know for sure whether or not it’s safe? Sorry, but you can’t know.  Don’t make the mistake of thinking that because it looks, smells, and tastes okay, it couldn’t be contaminated.  It could be.  You aren’t going to spend $100 or more to have a microbiology lab test your casserole, so deciding whether to serve it or discard it depends upon how much risk you’re willing to take. However, you should also want to consider the general health of those you intend to serve it to.  Some people are more likely than others to become ill from bacteria in a particular food. Particularly vulnerable are young children, the elderly, and people with weakened immune systems from cancer treatment, HIV, diabetes, or bone marrow or organ transplants.

More than 250 diseases are caused by contaminated food or drink.  You can protect yourself and your family by keeping foods out of the “danger zone” as much as possible.  Here are a few tips that might help you remember to get your leftovers back into the fridge quickly, something that’s not easy to do when you’re entertaining dinner guests at home. 

How Can I Remember  to Refrigerate Perishables Promptly?

• When you have dinner guests, refrigerate the perishable appetizers before you serve dinner (maybe while guests are eating salad).  It’s easy to forget about the appetizers if they’re in a different room. If you’re afraid you’ll forget them, ask someone else in the family to be responsible for getting perishable appetizers back in the fridge.
  
  
• Don’t cater to late-comers by leaving appetizers or entrées out at improper temperatures.  They won’t appreciate your delicious dinner if it makes them sick.
  
  
• Use hot plates or ice under platters. Once hot food has been cooked to the proper temperature, as long as it’s kept above 140°F, that time doesn’t count as part of the 2-hour limit.  The same is true of cold foods kept on the table or buffet at 40°F or below.
  
  
• Set a timer to remind you to put food back into the fridge 2 hours after it’s been out at room temperature.
  
  
• Take a last-minute look around the kitchen and dining room after meals and at bedtime to be sure that all perishables are in the fridge.
  
  
• Eating outdoors away from home creates additional challenges. When preparing food for a picnic or tailgating party, plan ahead ways to keep food at the right temperature or plan a menu that excludes perishable food.

Other Ways to Keep from Contaminating Food

Avoiding the “danger zone” is one important way to avoid food-borne illness, but not the only one. When you’re the chef, prepare food with clean hands and clean utensils.  Avoid cross-contamination from raw foods to ready-to-eat foods. For example, don’t cut a raw tomato on the same unwashed cutting board you used to quarter a raw chicken. (In fact, it’s a good idea to have one cutting board for meat and poultry and another for fruits and vegetables.) To avoid serving undercooked (and therefore possibly contaminated)  food, use a meat/poultry thermometer to measure the temperature, and consult a cooking chart to be sure the food reaches the minimum safe temperature before you permanently remove it from the oven.  

To learn more about bacteria in foods, click here: http://shelflifeadvice.com/content/why-does-refrigeration-keep-bacteria-multiplying.  Note the related Q/As listed on the right side.

Source(s):

Catherine Nettles Cutter, Ph.D., Pennsylvania State University, Dept. of Food Science

Joe Regenstein, Ph.D. Cornell University, Dept. of Food Science

Essortment.com  “Health Tips: A guide to Staphlococcus and foodborne illness”
http://www.essortment.com/all/foodborneillnes_rbla.htm

mmpcgastroenterology  “Foodborne Illness” 
http://www.mmpc.com/gastro_foodborneillness

Food Safety Information Council “Food Poisoning Bacteria
http://www.foodsafety.asn.au/factsheets/foodpoisoningbacteri2249.cfm

Link(s):

mmpcgastroenterology  “Foodborne Illness” 
http://www.mmpc.com/gastro_foodborneillness