Food Protection Connection: To Refrigerate or Not to Refrigerate, That is the Question

(reprinted from Dietary Manager, November/December 2011)

With today’s ever-changing packaging methods and types of packaging, especially with foodservice and institutional foods, most of us find ourselves confused as to whether to keep a food refrigerated before opening, after opening, or not refrigerated at all. Most people know when they see a jar or can of food that it does not require refrigeration, at least not until opened. But what about after it’s opened? Some opened foods need refrigeration, some do not. Does the label adequately tell you how to handle the food before and after opening? Most of us don’t have time to keep up with food packaging technology, we just want good quality food to serve and eat. So making a decision to refrigerate or not to refrigerate needs to be based on what we do know. As foodservice professionals we do, or should, understand food.

Refrigeration has long been used to control microbial growth on potentially hazardous foods. Failure to maintain temperature controls can result in microbiological growth of human pathogens that can cause foodborne illness. Refrigeration is just one barrier to controlling microbial growth. Acidification, preservation, salt content, water activity and similar, if used alone or in conjunction with one another, can provide alternative barriers to microbial growth. But most consumers are unaware if any of these other barriers are present in a product. People generally know that if they buy something from a refrigerated case, they should store it in a refrigerator; if they buy something from a store shelf, they can keep it in their pantry or storeroom. “Keep Refrigerated,” “Refrigerate After Opening,” and similar statements no longer provide meaningful information for consumers, since the same label statements occur on food requiring refrigeration for safety purposes, and on foods being refrigerated for product quality. Regulators often get calls from food facility operators and consumers who have purchased or used a food item, but accidentally left it out on the counter—oops! “Do I have to throw it out or can I put it in the refrigerator and keep it?’’ This question is not easily answered if you don’t understand the food and how pathogens can or cannot interact with it, and what the packaging type actually is for, quality or safety.

Those who read Food Protection Connection routinely should know what a potentially hazardous food is. But it’s always good to review. According to the FDA, a potentially hazardous food is “an animal food that is raw or heat-treated; a plant food that is heat treated or consists of raw seed sprouts, cut melons, cut leafy greens, cut tomatoes or mixtures of cut tomatoes that are not modified in a way so they are unable to support pathogenic microorganism growth or toxin formation;” and a food that because of the interaction of available water (Aw) and pH is unable to support pathogenic growth.

Refrigeration is just one of many barriers that can be used to control pathogenic microbial growth or toxin formation and is often the most practical. Failure to maintain refrigeration of a potentially hazardous food (i.e. temperature abuse) may result in the growth of harmful human foodborne pathogens. That is not to say that refrigerated foods do not or may not have pathogens present on them, but that if present, pathogen growth will significantly slow or stop.  Refrigeration is also used to slow down deterioration of a food’s color, flavor, and texture.  Nothing more than quality degradation will occur if non-potentially hazardous foods are held or stored at elevated temperatures.

In 1995, the National Advisory Committee on Microbiological Criteria for Foods (NACMCF), the Association of Food and Drug Officials (AFDO), the National Food Processors Association (NFPA), and the Centers for Disease Control and Prevention (CDC) recognized this type of labeling was confusing and misleading to consumers (and foodservice workers).  Knowing that proper refrigeration of potentially hazardous food was a key to the prevention of foodborne illness, they requested that the Food and Drug Administration (FDA) review the use of the voluntary label statements “Keep Refrigerated” and “Refrigerate After Opening”.  In a 1997 response, FDA agreed that “Keep Refrigerated” may “not be sufficient to warn consumers about a health risk” and provided recommended label language that would help clarify this issue.  Although this document was published to address the consumer’s perspective on understanding labels, it certainly would apply to the foodservice industry as well.

Although FDA published this guidance document 14 years ago to industry and recommended clearer, more meaningful statements, industry as a whole has not followed through with these recommendations. It still appears that consumers are confused, and labeling has not really changed much.

Ultimately it’s up to the ‘Person in Charge’ of a food facility and the consumer to know and understand their food and learn which need refrigeration for safety versus refrigeration for quality. In the foodservice industry and institutional facilities, this has become ever so complex as new packaging methods are popping up every day—packing for pathogen safety, packaging for quality, packing for ease of transportation, and packaging for ease of storage or cooking of the food, and even for consumption of the food. In FDA’s guidance document “Labeling of Foods That Need Refrigeration by Consumers,” FDA suggests three general  groups of foods and a recommended labeling statement for each category.

Group A Foods
These are foods that are potentially hazardous and, if subject to temperature abuse, will support the growth of infections or toxigenic microorganisms that may be present.  This is the category of foods that have a pH above 4.6, high water activity, have not received thermal processing or similar rendering them shelf stable, have no preservatives, or any other barriers to hinder pathogen growth.  These are your true potentially hazardous foods that have not been altered/packaged to render them non-potentially hazardous.  A whole raw turkey would be a food example of this group.

Suggested Language: “IMPORTANT Must Be Kept Refrigerated To Maintain Safety”

Group B Foods
These are foods that are shelf-stable as a result of processing, but once opened, the remaining food is potentially hazardous unless refrigerated. These products have a pH above 4.6, a high water activity, have received a thermal or similar treatment to destroy pathogens in the unopened package and have no other barriers, such as preservatives, salt content or similar to prevent growth after opening. These are potentially hazardous foods, which due to the alteration/packaging of the product are shelf stable while in unopened packages, but are most definitely still a potentially hazardous food once they are opened. A good example of this might be a thermally processed vacuum packed and boxed beef stew. On the shelf, the product is perfectly safe if exposed to elevated temperatures, but once opened it must be held at 41F or below.

Suggested Language: “IMPORTANT Must Be Refrigerated After Opening to Maintain Safety”

Group C Foods
These are foods that do not pose a safety hazard even after opening, but may experience a more rapid deterioration in quality over time if not refrigerated. Foods in this group will have one or more of the following qualities: Low pH (below 4.6), low available water, or other barriers such as preservatives, salt content, and acidification.  These are true NON-potentially hazardous foods.  There are no safety concerns with these foods if left out of refrigeration after opening.  Good examples in this group are dill pickles and mustard.  They all say Refrigerate After Opening, but it is labeled this way for quality, not safety.

Suggested Language: “Refrigerate for Quality”

FDA strongly recommends that Group C labeling should not be used on Group A or B foods to avoid any confusion between foods refrigerated for quality and those refrigerated for safety.

Speaking of confusion, are you confused yet?  I don’t know about you, but I rarely see products with “Refrigerate for Quality” or any of these suggested voluntary statements.  What I do know is that you need to take your knowledge of what a potentially hazardous food is and apply it to your decision-making process when determining whether or not to refrigerate.  Foodservice operators should have a discussion with their distributors and/or food manufacturers about refrigeration of products if it is not clear on the packaging.  Food facility operators need to understand every food they have in their facilities before they begin using them.  There just won’t be time to research or make calls when you are in the midst of producing hundreds of meals and the question comes up.

With today’s ever-changing technology of food preservation and packaging you simply can’t rely on how a product is packaged, shipped, or displayed to know whether or not to refrigerate it…and you certainly can’t rely on the voluntary label statement.  You must use good, sound food safety knowledge.  If a food is a potentially hazardous food, refrigerate it.  If it is a potentially hazardous food, but is packaged to make it shelf stable, refrigerate it after opening.  If it is a non-potentially hazardous food, you don’t have to refrigerate it, but may choose to for quality and to extend its shelf life.

Of course, if all else fails and you are just not sure what to do with a particular food, make the safest choice…refrigerate it.

by Melissa Vaccaro, MS, CHO
Melissa Vaccaro, MS, CHO is a Food Program Specialist for the PA Department of Agriculture and an Executive Board Member for the Central Atlantic States Association of Food Drug Officials (CASA). Contact her at mvaccaro@state.pa.us.