What Happens When Food Is Placed in the Refrigerator?

You’ve just arrived home with that tempting slice of cake left over from the party, or the fresh, vibrant fruits you bought at the market. What's the common destination to keep them longer? The fridge, of course! But what really happens to these foods when we place them in that cold and often noisy environment?

   

For the everyday consumer, the refrigerator is a natural extension of the kitchen, a sanctuary against the dreaded "spoiled."

For the food business entrepreneur, it represents the fine line between profit and loss, the key to extending the shelf life of ingredients and products.

And for the food science university student, the fridge is a living lab, the stage for fascinating biochemical reactions and a practical example of preservation principles.

Let's embark on a journey to unravel the mystery of the refrigerator, exploring what happens to our food in that magical cold environment, from the microscopic level to practical tips for efficient storage.

   

The Science of Cold Preservation: Decelerating Time

At the core of the refrigerator's ability to preserve food is a fundamental scientific principle: the reduction of the speed of chemical and biological reactions.

Think of a car at high speed; it covers a great distance in a short time. Similarly, chemical reactions and microbial growth in food occur rapidly at higher temperatures.

The refrigerator acts like a brake, dramatically slowing down this speed.   

What Happens to Microorganisms?

Bacteria, fungi, and yeasts are the main villains of food shelf life. They multiply rapidly at room temperatures, consuming the food's nutrients and producing subproducts that alter its flavor, odor, texture, and, in some cases, make it unsafe for consumption.

• Multiplication Reduction: The low temperature in the fridge does not kill most of these microorganisms, but it significantly slows down their multiplication rate.

• Imagine a bacterium that divides every 20 minutes at room temperature; in the fridge, this process can take hours or even days.

• Enzyme Inhibition: Microorganisms produce enzymes that catalyze spoilage reactions. Refrigeration decreases the activity of these enzymes, slowing down the decomposition process.

Did you know that some microorganisms can pose a serious health risk if they find the ideal conditions to multiply?

An example is the Salmonella, a common bacterium in contaminated food that can cause serious infections.

To better understand this danger and how to prevent it, check out our full article on "Salmonella in Foods: Sources of Contamination, Symptoms, and Prevention in Restaurants and Markets".

What Happens to the Food's Natural Enzymes?

Foods themselves contain enzymes that remain active after harvest or slaughter. These enzymes are responsible for processes such as the ripening of fruits and vegetables, the browning of cuts, and changes in texture.

• Slowing Down Ripening: Refrigeration slows down the enzymes responsible for ripening, allowing fruits and vegetables to remain fresh longer.

• Think of a banana; it ripens much more slowly in the fridge than on the fruit bowl.

• Minimizing Undesirable Changes: The low temperature also delays the enzymes that cause browning in cut apples or the loss of firmness in cooked vegetables.

   

What Happens to Moisture?

The refrigerator also plays a role in moisture control, although this effect can be both positive and negative depending on the food.

• Reduced Water Loss: The cold and generally enclosed environment of the refrigerator helps reduce the rate of water evaporation from food, preventing the drying out of leaves, meats, and other products.

• Condensation Control: However, the temperature difference between the food and the refrigerator air can lead to condensation, especially in food stored without proper packaging. This excessive moisture can sometimes favor mold growth.

The Refrigerator as a Business Strategy: Preserving Quality and Reducing Waste

• Extending Ingredient Shelf Life: By storing fresh ingredients under refrigeration, restaurants, bakeries, and small producers can reduce waste and better plan their purchases, avoiding losses due to spoilage.

• Preserving Processed Products: Refrigeration is essential for maintaining the quality and safety of many processed products, such as cakes, fillings, sauces, and meat preparations, extending their shelf life and enabling larger-scale production.

• Ensuring Food Safety: Maintaining proper temperatures in the refrigerator is a Critical Control Point (CCP) in any food safety system, such as HACCP. It helps prevent the multiplication of pathogenic bacteria that can cause foodborne illnesses.

• Optimizing Workflow: Proper refrigeration allows entrepreneurs to prepare ingredients in advance, optimizing the workflow in the kitchen and reducing preparation time during peak hours.

   

The Refrigerator in Food Science: Preservation Principles in Action

• Microbial Inhibition: Refrigeration clearly demonstrates how reducing temperature impacts the kinetics of microbial growth, a fundamental concept in food microbiology.

• Enzymatic Activity Control: Refrigerated storage illustrates the effect of temperature on the activity of the food's endogenous enzymes, an important aspect of food biochemistry.

• Heat and Mass Transfer: Understanding how heat is removed from food and how moisture moves within the refrigerator and between the food and the environment is crucial for optimizing storage.

• Packaging and Modified Atmosphere: The refrigerator also serves as a starting point for understanding how different types of packaging and modified atmosphere techniques (using gases like nitrogen and carbon dioxide) can complement refrigeration to further extend food shelf life.

Efficient and Safe Refrigeration: Practical Tips for Daily Life

• Maintain the Correct Temperature: The ideal refrigerator temperature should be between 0°C and 5°C (32°F and 41°F). Use a thermometer to check regularly. Temperatures above 5°C can allow for faster bacterial growth.

• Do Not Overload the Refrigerator: Cold air needs to circulate to keep all food at the proper temperature. An overly full refrigerator hinders this circulation.

• Store Food Correctly:

• Raw Meats: Store on the bottom shelves, in sealed containers, to prevent their fluids from contaminating other foods.

• Dairy Products: Keep on the middle shelves, where the temperature is more constant.

• Fruits and Vegetables: Use the specific drawers, which generally have humidity control. Wash them only before consumption.

• Leftovers: Cool quickly (within 2 hours) and store in shallow, sealed containers. Consume within 3-4 days.

• Ready-to-Eat Foods: Keep on the top shelves, away from raw foods.

Another important food safety concern is Listeria monocytogenes, a bacterium that, unlike many others, can multiply at refrigeration temperatures.

It is crucial to know the high-risk foods and hygiene practices to avoid listeriosis.

Explore our detailed article on "Listeria monocytogenes: How to Protect Your Establishment and Ensure Food Safety" to stay informed.

• Use Appropriate Packaging: Airtight containers and plastic wrap help protect food from contamination, moisture loss, and odor absorption.

• Cool Hot Foods Before Storing: Placing hot food directly into the refrigerator raises the internal temperature, hindering the preservation of other items and requiring more energy from the appliance.

• Clean the Refrigerator Regularly: Cleaning helps remove spills, molds, and bacteria that could contaminate other foods.

• Pay Attention to Expiration Dates: Refrigeration slows deterioration, but it does not stop it indefinitely. Respect the expiration dates indicated on the packaging.

• Strange Odor? Warning Sign! If refrigerated food shows a strange odor, color, or texture, discard it, even if it is within the expiration date.

The Refrigerator in the Global Chain: Essential Control Point

Even in vast global supply chains, the refrigerator, in its various forms (cold rooms, refrigerated containers, display cases), acts as a crucial temperature control point.

From the rapid cooling of carcasses in slaughterhouses to the storage of fruits and vegetables during maritime transport and the preservation of dairy products in supermarkets, maintaining the cold chain is essential to ensure that food arrives safely and with quality to the final consumer.

Constant temperature monitoring and accurate recording are indispensable practices to ensure the integrity of food throughout this complex global journey.

   

Conclusion: Mastering the Cold for a Safe and Fresh Food Future

The refrigerator, an appliance omnipresent in our lives, is much more than a simple cold box.

It is a stage for complex scientific processes, a vital tool for entrepreneurs, and a practical laboratory for students.

By understanding what truly happens to food when we put it in the fridge, we can optimize its use, reduce waste, and, most importantly, ensure the safety and quality of the food we consume, whether in our home or in a world connected by long supply chains.

Mastering the power of cold is a fundamental step toward building a safer, fresher, and more sustainable food future for everyone.

    

Need help implementing safe food preservation practices in your business or have questions about food safety?

Our specialized food and food safety consultancy can help you optimize your processes, ensure the quality of your products, and avoid risks.

Contact us to learn more about our personalized services.

Or, if you prefer, explore our free content on the website to access guides, checklists, and valuable information on food safety and preservation.