Refrigeration and Food Safety: How to Keep Your Fridge Clean and Bacteria Free

The refrigerator stands as a vital cornerstone of kitchen equipment, safeguarding the integrity of our food. In our modern age, these electric marvels have become so ubiquitous that we easily overlook their humble origins—a mere box reliant on ice blocks for cooling. Yet, the gravity of their role in our lives becomes instantly apparent during power outages or malfunctions, endangering the safety of our food supply.

History of Refrigeration

In ancient times, humans discovered that storing game in cool caves or snow prolonged its freshness, ensuring sustenance during scarcity. Subsequently, ice harvesting in winter facilitated preservation through summer months. With industrialization, ice collection expanded to lakes and rivers, later transitioning to manufactured ice, transported worldwide.

An interim phase in food cooling history involved adding chemicals like sodium nitrate or potassium nitrate to water, lowering temperatures. This technique, recorded in 1550, marked the inception of "refrigeration." Mechanical refrigeration, employing compressors and refrigerants, emerged gradually, introduced in the late 19th century.

Refrigeration science has evolved, notably in 1996, with the adoption of HFC 134a to comply with environmental regulations like the Clean Air Act, Title 6. This replacement of "freon," a common tradename for the old refrigerant, ensured ozone preservation while maintaining food freshness effectively. For consumers, the transition should be seamless.

Importance of Refrigeration

Refrigeration inhibits bacterial proliferation. Bacteria are omnipresent in nature, dwelling in soil, air, water, and our food. Under favorable conditions—nutrients, moisture, and appropriate temperatures—they multiply swiftly, posing health risks. The optimal temperature for bacterial growth, known as the "Danger Zone," lies between 40 and 140 °F, with some strains doubling every 20 minutes. Maintaining a refrigerator temperature at 40 °F or below effectively safeguards most foods.

Types of Bacteria in Refrigerated Foods

Two distinct bacterial families exist: pathogenic bacteria, responsible for foodborne illnesses, and spoilage bacteria, inducing food decay and unpleasant sensory changes.

Pathogenic bacteria proliferate swiftly within the "Danger Zone," spanning 40 to 140 °F, yet they typically do not alter the taste, aroma, or appearance of food. Hence, the presence of pathogens often remains undetectable.

Spoilage bacteria thrive even in low temperatures, such as those found in refrigerators, eventually leading to the development of undesirable tastes and odors in food. While most individuals would opt against consuming spoiled food, the likelihood of illness resulting from its consumption is generally low. It comes down to an issue of quality versus safety:

  • Food that has been left too long on the counter may be dangerous to eat, but could look fine.
  • Food that has been stored too long in the refrigerator or freezer may be of lessened quality, but most likely would not make anyone sick. (However, some bacteria such as Listeria monocytogenes thrive at cold temperatures, and if present, will multiply in the refrigerator over time and could cause illness.)

Safe Refrigerator Temperature

Ensuring refrigerator safety involves monitoring its temperature. Refrigerators should be set to maintain a temperature of 40 °F or lower. Some models come equipped with built-in thermometers for internal temperature measurement. For those lacking this feature, using an appliance thermometer inside the refrigerator is advisable, especially during power outages. If, after power restoration, the refrigerator maintains a temperature of 40 °F, the food remains safe. Any food left above 40 °F for more than 2 hours should be discarded. Appliance thermometers are specifically designed for accurate cold temperature readings. Additionally, it's crucial to keep refrigerator and freezer doors tightly closed, minimizing unnecessary openings and promptly closing them after use.

Safe Handling of Foods for Refrigerating

Hot food can either be directly placed in the refrigerator or rapidly cooled in an ice or cold water bath before refrigeration. Covering the food helps maintain moisture and prevents absorption of odors from other foods.

For large quantities of food like soup or stew, it's advisable to divide them into smaller portions and store them in shallow containers before refrigerating. Similarly, large cuts of meat or whole poultry should be divided into smaller pieces or placed in shallow containers prior to refrigeration.

Placement of Foods

The refrigerator's temperature should consistently remain at 40 °F or lower in all areas, ensuring safe storage for any type of food. Raw meat, poultry, and seafood should be securely wrapped or stored in sealed containers to prevent their juices from contaminating other items.

Certain refrigerators offer special features like adjustable shelves, door bins, crispers, and designated compartments for meat and cheese. These features are intended to enhance food storage convenience and create an optimal environment for storing fruits, vegetables, meats, poultry, and cheese.


Shelves should offer adjustable configurations to accommodate various package sizes. Tempered glass shelves, both appealing and simple to clean, are commonly preferred. Certain refrigerators boast sealed glass shelves, designed to confine spills and simplify cleaning tasks. Additionally, some shelves are equipped with pull-out functionality to enhance accessibility to items stored at the back.

Specialized Compartments

Sealed crisper drawers offer an ideal storage setting for both fruits and vegetables. Vegetables thrive in higher humidity, while fruits prefer lower humidity. Certain crispers feature adjustable controls, empowering consumers to tailor the humidity levels in each drawer according to their needs.

An adjustable temperature meat drawer enhances the storage lifespan of meats and cheeses. Extra cool air is channeled into the drawer to maintain items at a very cold temperature without freezing them.

Safety of Foods Stored on the Door

Avoid storing perishable foods in the refrigerator door. Instead, place eggs in their carton on a shelf. The temperature in storage bins on the door tends to fluctuate more than within the main cabinet. Minimize door openings to maintain stable temperatures.

Food Safety While Manually Defrosting a Refrigerator-Freezer

Most refrigerators-freezers available nowadays don't necessitate consumer defrosting. However, some units still on the market or in homes do accumulate frost and require occasional defrosting.

When defrosting the freezer and turning off the unit, it's vital to keep refrigerated foods chilled and frozen items from thawing. To achieve this, place the food in a cooler with a cold source or pack it in a box covered with blankets for insulation.

Avoid using electrical heating devices, ice picks, knives, or any sharp objects to remove frost, as this may cause damage to the inner lining.

Keeping the Refrigerator Clean

Maintaining a clean refrigerator is crucial for food safety. Promptly wipe up spills with hot, soapy water, ensuring thorough cleaning and rinsing.

As a weekly routine, discard perishable foods that are no longer safe to eat. Cooked leftovers typically remain fresh for up to 4 days, while raw poultry and ground meats should be consumed within 1 to 2 days. Consult a cold storage chart for guidance on storing meat, poultry, and egg products in the refrigerator.

To maintain a fresh-smelling refrigerator and combat odors, place an open box of baking soda on a shelf. Avoid using solvent-based cleaning agents, abrasives, or cleansers that may affect the taste of food or cause damage to the refrigerator's interior finish. Follow the manufacturer's instructions carefully.

For exterior cleaning, use a soft cloth with mild liquid dishwashing detergent or products specifically formulated for appliance use. Ensure the front grill remains free of dust and lint to promote proper air flow to the condenser. Periodically clean the condenser coil with a brush or vacuum cleaner to remove dirt and lint buildup, ensuring efficiency and optimal performance.

Removing Odors

Removing lingering odors caused by spoiled food in a refrigerator, particularly after events like a power outage, can be challenging. The following procedures may have to be repeated.

  • Wipe the interior of the unit with a mixture of equal parts vinegar and water to harness vinegar's acidity, which helps combat mildew.
  • Clean the interior with a baking soda and water solution, ensuring thorough scrubbing of gaskets, shelves, sides, and the door. Allow it to air out for several days.
  • Fill the unit with rolled newspapers, shut the door, and leave it for several days. Afterward, remove the newspapers and clean the interior with vinegar and water.
  • Sprinkle fresh coffee grounds or baking soda loosely in the bottom of the unit, or place them in an open container to absorb odors.
  • Place a cotton swab soaked with vanilla inside the freezer, close the door for 24 hours, and then check for lingering odors.
  • Utilize a commercial product available at hardware and housewares stores, following the manufacturer's instructions carefully.

Storage Times For Refrigerated Foods
Ground Meat, Ground Poultry, and Stew Meat
Ground beef, turkey, veal, pork, lamb 1-2 days
Stew meats 1-2 days
Fresh Meat (Beef, Veal, Lamb, and Pork)
Steaks, chops, roasts 3-5 days
Variety meats (Tongue, kidneys, liver, heart, chitterlings) 1-2 days
Fresh Poultry
Chicken or turkey, whole 1-2 days
Chicken or turkey, parts 1-2 days
Giblets 1-2 days
Bacon and Sausage
Bacon 7 days
Sausage, raw from meat or poultry 1-2 days
Smoked breakfast links, patties 7 days
Summer sausage labeled "Keep Refrigerated" Unopened, 3 months;
Opened, 3 weeks
Hard sausage (such as Pepperoni) 2-3 weeks
Ham, Corned Beef
Ham, canned, labeled "Keep Refrigerated" Unopened, 6-9 months;
Opened, 3-5 days
Ham, fully cooked, whole 7 days
Ham, fully cooked, half 3-5 days
Ham, fully cooked, slices 3-4 days
Corned beef in pouch with pickling juices 5-7 days
Hot Dogs and Luncheon Meats
Hot dogs Unopened package, 2 weeks;
Opened package, 1 week
Luncheon meats Unopened package, 2 weeks;
Opened package, 3-5 days
Deli and Vacuum-Packed Products
Store-prepared (or homemade) egg, chicken, tuna, ham, and macaroni salads 3-5 days
Pre-stuffed pork, lamb chops, and chicken breasts 1 day
Store-cooked dinners and entrees 3-4 days
Commercial brand vacuum-packed dinners with/USDA seal, unopened 2 weeks
Cooked Meat, Poultry, and Fish Leftovers
Pieces and cooked casseroles 3-4 days
Gravy and broth, patties, and nuggets 3-4 days
Soups and Stews 3-4 days
Fresh Fish and Shellfish
Fresh Fish and Shellfish 1-2 days
Fresh, in shell 3-5 weeks
Raw yolks, whites 2-4 days
Hard-cooked 1 week
Liquid pasteurized eggs, egg substitutes Unopened, 10 days;
Opened, 3 days
Cooked egg dishes 3-4 days

Table sourced from FSIS

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