Preservative: Preserving our food and Health

March 29, 2023

When it comes to food, freshness, taste, and safety are paramount. But have you ever considered the intricacies of food preservation? Modern food processing relies on preservatives to guarantee the security and flavor of our food. However, with the plethora of preservatives available, it can take time to comprehend their usage and safety. Thus, in the ensuing discourse, we shall delve into the various food preservatives, how to use them safely and effectively, and what alternatives to preservatives are.

1.  What are preservatives?

Preservatives are ubiquitous in our food supply, present in everything from the packaged snacks in our pantries to the fruits and vegetables we purchase at supermarkets. However, what are they exactly, and why are they so widespread? In this discussion, we shall explore the definition of preservatives and their advantages.

1.1 Definition of preservatives

Preservatives are chemical or natural substances incorporated into food to prevent spoilage and prolong its shelf life. They function by impeding the growth of microorganisms or hindering the chemical processes that cause food to degrade and spoil.

1.2 Benefits of Preservatives

  • Extending shelf life

Preservatives work by inhibiting the growth of microorganisms that can cause food spoilage, such as bacteria, yeast, and mold. This helps to prevent food from spoiling and becoming unsafe to eat, allowing for a longer storage and distribution time.

  • Maintaining food quality

Preservatives do more than just keep our food safe; they also help maintain our favorite food products' taste, texture, and appearance. For example, certain preservatives can prevent fats and oils from oxidizing, which can cause an unpleasant rancid taste in nuts, seeds, and oils. Other preservatives can prevent fruits and vegetables from changing color or texture, ensuring they remain fresh and delicious for longer. This allows us to savor our preferred foods without concern for their quality diminishing over time.

  • Preventing foodborne illnesses

Preventing foodborne illnesses is necessary inadequate food preparation and storage conditions can be the culprits. However, using preservatives can help mitigate these risks by stopping the growth of microorganisms that can lead to spoilage and contamination.

For instance, citric acid, vinegar, and salt can create an acidic environment that inhibits the growth of bacteria. At the same time, nitrates and nitrites can prevent the growth of harmful bacteria and parasites in meat products, such as botulism.

  • Lowering food costs

Lowering food costs is possible with preservatives, which extend the shelf life of food products. As a result, food manufacturers and retailers can transport and store products for more prolonged periods, reducing the need for frequent restocking and ultimately lowering overall costs.

  • Increasing food availability

In addition, preservatives can increase the availability of perishable foods by extending their shelf life, making them more accessible to consumers, especially in areas where fresh produce or refrigeration facilities are limited.

2.  Uses of preservatives

The food industry uses preservatives in various ways to preserve the quality and safety of food products. Here are some common uses of preservatives in food:

  • Inhibiting bacterial growth

Preservatives are a standard method used in food to prevent the growth of bacteria, mold, and other microorganisms that cause spoilage and foodborne illnesses. For instance, food manufacturers frequently add sodium benzoate and potassium sorbate to acidic food products like fruit juices, soft drinks, and pickles to inhibit the growth of bacteria and fungi. Sodium nitrite is another example that prevents the growth of harmful bacteria, such as Clostridium botulinum, often present in cured meats such as bacon, ham, and hot dogs.

  • Preventing oxidation

Preservatives are crucial in maintaining the quality and safety of food products by preventing oxidation, retaining freshness, and lowering food pH.

Oxidation can cause changes in the flavor, texture, and color of the food product. So, preservatives like tocopherols, ascorbic acid, and citric acid are commonly used to prevent oxidation in food products that contain fats and oils.

  • Maintaining freshness

Keeping food fresh is essential for ensuring it remains safe and enjoyable. That's why preservatives are often added to food products to prevent the growth of mold, bacteria, and other microorganisms that can cause spoilage and reduce their shelf life. One example is sulfites like sodium metabisulfite and potassium metabisulfite, commonly used in dried fruits, wine, and beer to prevent mold and bacteria growth.

  • Lowering pH

Another way preservatives work is by lowering the pH of food products using acids like acetic acid and lactic acid. By doing so, they can inhibit the growth of bacteria and help preserve the food. It's incredible to think how minor adjustments like lowering the pH can have such a significant impact on the shelf life of food products.

3.  Types of preservatives in food

When it comes to preserving our food, there are all sorts of methods used - some natural, some not so much. Let's delve into the fascinating world of food preservatives! We'll be exploring the different types used in food products, from good old-fashioned salt and sugar to the more synthetic options like sorbic acid and sodium benzoate.

3.1 Natural preservatives

Natural preservatives are substances that occur naturally in foods or can be derived from natural sources such as plants or animals. Here's a deeper dive into natural preservatives, including some examples of commonly used ones and how they work to preserve food.

  • Vinegar

What you may not know is that vinegar is also a natural preservative. It is typically made from fermented ethanol and contains acetic acid, which gives it its distinctive sour taste and antimicrobial properties. People often use vinegar to preserve fruits and vegetables and pickles and condiments like ketchup and mustard.

  • Salt

You surely know that salt is a preservative. In your daily life, you may have used salt when pickling food. Adding salt to food creates an environment unsuitable for bacteria and other microorganisms to thrive in, preventing spoilage. That's why salt is a popular choice for preserving meats, fish, and veggies. Not only does it act as a preservative, but salt also adds flavor and can improve the texture of food.

  • Sugar

People often use sugar just as frequently as vinegar and salt for food preservation. When added to food, sugar creates an unfavorable environment for the growth of bacteria and other microorganisms that can cause spoilage. That is why sugar is a popular choice for preserving food, as it helps to extend the shelf life of products and prevents them from spoiling too quickly.

  • Citric acid

Remember citric acid? We discussed it earlier as an acidity regulator, but did you know it's also a natural food preservative? Adding citric acid to food creates an acidic environment that stops the growth of bacteria and fungi that can spoil food. That's why you'll often see it in jams, soft drinks, and meats.

  • Rosemary

This herb is famous for its strong and pleasant aroma, but did you know that rosemary extract also contains natural antioxidants that can prevent spoilage in food? When added to meats, baked goods, and even some beverages, rosemary extract can help extend their shelf life and maintain quality.

  • Clove oil

The oil is extracted from the flower buds of the clove tree, which can effectively inhibit the growth of bacteria and fungi. It's commonly added to meat products, baked goods, and even tea. Besides extending your food's shelf life, clove oil adds a distinctive flavor and aroma.

3.2 How do natural preservatives work?

Natural preservatives work in various ways to inhibit the growth of bacteria, mold, and other microorganisms that can spoil food. Here are some examples:

  1. Lowering pH: Vinegar and citric acid are natural preservatives that lower food pH, creating an acidic environment that stops bacterial growth. It helps prevent spoilage and increases the food's shelf life.
  2. Dehydration: Salt and sugar are natural preservatives that dehydrate food. Adding salt or sugar to food removes water, making it less hospitable to bacterial growth.
  3. Antimicrobial properties: Rosemary extract and clove oil are natural preservatives that contain antimicrobial compounds. These compounds can prevent the growth of bacteria and other microorganisms that cause spoilage.
  4. Enzyme inhibitors: Garlic and onion contain enzyme inhibitors. Enzymes cause food to spoil, so by inhibiting them, these natural preservatives can prevent spoilage.

3.3 Chemical Preservatives

Chemical preservatives are substances added to food to prevent spoilage, inhibit the growth of microorganisms, and extend the product's shelf life. Here are some examples of chemical preservatives:

  • Sodium benzoate

Sodium benzoate is a chemical preservative widely used in the food industry. It breaks down into benzoic acid, which can penetrate microorganisms and disrupt their cellular processes, ultimately causing their demise. It effectively inhibits the growth of bacteria, yeast, and mold, and food manufacturers commonly add it to acidic foods such as carbonated drinks, fruit juices, and pickles.

  • Sodium sulfite

Sodium sulfite, a common chemical preservative in the food industry, releases sulfur dioxide, which acts as an antimicrobial agent and inhibits food oxidation. It finds wide application in dried fruits, wine, and other processed foods.

  • Calcium propionate

Calcium propionate is a chemical preservative frequently added to bread and baked goods to prevent mold growth and other microorganisms that cause spoilage. It inhibits mold growth and other organisms that cause spoilage in bread and baked goods.

  • Potassium sorbate

Potassium sorbate is commonly used as a chemical preservative in the food and beverage industry due to its ability to inhibit the growth of mold, yeast, and bacteria. It's added to various products, including cheese, wine, and baked goods, to prevent spoilage.

  • BHT

BHT, which stands for butylated hydroxytoluene, is a synthetic antioxidant used to prevent the oxidation of fats and oils in food. Because oxidation can cause food spoilage and rancidity. Snack foods, baked goods, and other processed foods often contain BHT to extend their shelf life.

3.4 How do chemical preservatives work?

Chemical preservatives inhibit the growth and activity of microorganisms such as bacteria, yeast, and mold. They can do this in several ways, such as:

1. Disrupting the cell membranes of microorganisms.

For example, sodium benzoate and sorbic acid can penetrate the cell walls of bacteria and fungi, leading to the breakdown of cellular processes and ultimately killing the microorganisms.

2. Prevent the formation of spores or reproductive structures.

Calcium propionate and propionic acid derivatives inhibit the growth of molds and other organisms by preventing the formation of reproductive systems. This extends the shelf life of food by preventing microorganisms from reproducing and spreading. On the other hand, sodium nitrate and sodium nitrite inhibit the growth of bacteria causing botulism by preventing the formation of spores.

3. Block the production of enzymes

Chemical preservatives are like tiny superheroes that come to the rescue of our food products! They can stop microorganisms in their tracks by disrupting their metabolic processes. It means they can control the production of essential enzymes that microorganisms need to grow and survive, including DNA and RNA synthesis, energy production pathways, and cellular signaling pathways. By throwing a wrench in these processes, chemical preservatives can prevent the spread of harmful bacteria, yeast, and mold, keeping our food safe and tasty.

  • Release of oxygen or other reactive compounds

Certain chemical preservatives have a more direct approach to eliminating microorganisms. They do this by releasing reactive compounds or oxygen, which destroys the microorganisms. These preservatives go ahead to break down cell membranes and other structures of the microorganisms, thus resulting in their death.

4.  Preservative examples

Have you ever noticed how much of the food we buy in stores have preservatives added? These added preservatives allow the food to be transported and stored for long periods without spoiling. So, let's take a closer look at food with preservatives!


You can enjoy bread in various ways, from a simple toast to a filling sandwich. It is a delicious and easy-to-eat food that many people love. But have you ever wondered how bread stays fresh for so long? That's where preservatives come in. Common preservatives in bread include calcium propionate, potassium sorbate, and sorbic acid. These additives work by inhibiting mold growth and other microorganisms that can cause the bread to spoil. So, next time you enjoy a slice of bread, thank those preservatives for keeping it fresh!

2. Cheese

Cheese is an amazing food that can be used in countless ways, from a topping on pizza to a delicious addition to a charcuterie board. But if you don't store it correctly, your cheese can go bad quickly. That's where preservatives come in! Natamycin, potassium sorbate, and sorbic acid are common preservatives added to the cheese. These preservatives prevent the growth of bacteria and mold that can spoil the cheese while maintaining its texture and flavor. And as a bonus, preservatives also make it possible to transport and sell cheese over longer distances.

3. Canned foods

Canning is a simple yet effective method for preserving food. Harmful bacteria and microorganisms are killed off by sealing them in an airtight container and subjecting it to high temperatures. However, spoilage is still possible if the process isn't done correctly.

Manufacturers often add preservatives to canned foods to prevent spoilage and ensure safety. These preservatives, such as citric acid, ascorbic acid, and sodium benzoate, work by inhibiting the growth of bacteria and other microorganisms.

4. Meat products

Many manufacturers use preservatives to preserve the freshness and quality of meat products. Common preservatives in meat products include nitrates and nitrites, added to cured meats like ham, bacon, and salami. Nitrates and nitrites help preserve the color and flavor of cured meats and inhibit the growth of harmful bacteria, such as Clostridium botulinum.

5. Snack foods

Oxidation can cause snacks to spoil, and adding preservatives helps prevent oxidation of the fats and oils in snacks. Manufacturers commonly add BHA, BHT, and TBHQ to potato chips, crackers, and other processed snacks.

6. Soft drinks

One common preservative in soft drinks is sodium benzoate, which helps prevent the growth of bacteria and molds. Manufacturers often use citric acid, which has flavor-enhancing and preservative properties, in conjunction with this particular preservative.

Another preservative in soft drinks is potassium sorbate, which is effective against yeast and molds. Food manufacturers often use it in conjunction with other preservatives, such as sodium benzoate, to increase the shelf life of their products.

5.  How to use preservatives?

Preservatives are crucial for various industries, and with adequate knowledge and techniques, you can utilize them efficiently and securely. This discussion will explore the proper utilization and storage of products containing preservatives.

  1. Choose the correct type of preservative for your product: Many different preservatives are available, including natural and synthetic options. Some preservatives are better suited for certain products than others, so choosing the right one for your needs is essential.
  2. Determine the appropriate amount of preservative to use: The amount of preservative you need will depend on various factors, such as the type of product, the pH level, and the desired shelf life. Follow the manufacturer's instructions carefully and use the recommended amount to ensure effectiveness and safety.
  3. Mix the preservative thoroughly into your product: Once you've determined the appropriate amount, mix it thoroughly to ensure even distribution is essential. It can be done by stirring or shaking the product until the preservative is fully incorporated.
  4. Store and handle products containing preservatives properly: Products containing preservatives should be stored in a cool, dry place away from direct sunlight and heat. Following good hygiene practices when handling these products is essential to prevent contamination.

6.  Alternatives to Preservatives

Have you ever wondered if there are alternatives to preservatives? While preservatives are crucial for preventing the growth of harmful microorganisms in various products, some consumers may prefer natural or alternative preservation methods. So, we'll explore some of these alternatives and how they work to ensure product safety and freshness.

6.1 Natural Methods of Food Preservation

  • Dehydration

Dehydration involves removing moisture from food, which inhibits the growth of bacteria and other microorganisms that can cause spoilage. This can be done by sun-drying, air-drying, or using a dehydrator.

  • Fermentation

Conversely, fermentation involves allowing beneficial bacteria to grow in the food, which produces lactic acid and other compounds that act as natural preservatives. Sauerkraut, kimchi, and yogurt are examples of fermented foods.

6.2 Modern methods of food preservation

  • Irradiation

Irradiation is a modern food preservation method that involves exposing food to ionizing radiation to eliminate bacteria, viruses, and other microorganisms that can cause spoilage or illness. This process uses gamma rays, electron beams, or X-rays to extend the shelf life of food, reduce the risk of foodborne illness, and improve food safety. Various regulatory agencies worldwide have approved irradiation use, including the US Food and Drug Administration and the World Health Organization. However, the use of irradiation is strictly regulated, and products that have undergone this process must be labeled accordingly.

  • High-pressure processing

High-pressure processing (HPP) is a food preservation technique that uses high pressure to eliminate harmful bacteria and is often used as an alternative to traditional thermal pasteurization. The process involves placing the food in a container and subjecting it to high-pressure levels, typically between 100 and 600 MPa (megapascals), for some time. This pressure can help to inactivate bacteria, viruses, and enzymes that can cause food spoilage or illness.

HPP is used to preserve products such as juices, guacamole, salsa, deli meats, and seafood. The technique effectively extends the shelf life of these products and maintains their quality and nutritional value.

Preservatives shield us from harmful microbes that taint our food and other products. Despite some consumers' misgivings about preservatives, it's crucial to recognize the vast benefits they offer. Following the food additives manufacturer's instructions precisely is critical to using preservatives safely and efficiently. With the proper knowledge and techniques, we can rely on preservatives to safeguard our food, health, and overall well-being.

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