Preservatives – Keeping our foods safe & fresh

In this 101 series installment, we'll take a look at the role preservatives play in keeping our food supply safe and fresh.

As sustainability and food waste reduction becomes an ever-more important part of our food systems, we believe it’s essential to explore the ways we reduce food waste and increase food safety and freshness through the use of preservatives.
Preservatives are crucial to the preservation, safety, and freshness of the foods in our global food supply system. Many of the foods we enjoy are possible because of modern (and ancient) preservation techniques. Let’s explore the varying ways we keep our foods fresh, safe, and shelf-stable. 

What do preservatives do?

Preservatives and preservation techniques prevent foods from spoiling and oxidizing quickly, allowing grocery manufacturers to distribute foods across the country and the globe without impacting food safety or quality. Two significant factors that cause foods to go bad quickly are microbes and oxidation.
Microbes that cause spoiling are undesirable bacteria, fungi, and yeasts that can grow in our food products. These microorganisms feed off the foods’ nutrients and can cause serious harm to humans if consumed. Without preservatives, bacteria such as listeria and botulism can invade our foods and if consumed by humans, can cause us to become critically ill. Less harmful bacteria, fungi, and yeasts will grow on foods making them inedible.
Oxidation, which is a term for certain types of chemical reactions, can impact food safety and flavor by cause an undesirable chemical change that can turn fats rancid and can cause vegetables and fruits, such as cut potatoes and apples, to brown. Enzymes and other chemical breakdown processes are responsible for the oxidation that transforms foods into an unpalatable, and at times, unsafe product.

What are preservation techniques?

Preservatives are the ingredients and processes we apply to our foods to keep them safe and shelf-stable. There are two key ways we preserve our foods: chemical preservation and physical preservation.
Chemical preservation involves adding specific ingredients to foods and food packaging that allows the food to remain safe and fresh. Humans have been using chemical preservation for thousands of years and familiar food products such as yogurt, sauerkraut, and kimchi are examples of foods that have undergone chemical preservation.
Physical preservation involves different techniques such as salt curing, refrigeration, smoking, drying, and more to protect food quality. As with chemical preservation, humans have been using physical means to preserve foods since ancient times. One such example is drying and smoking meats, veggies, and more.
These techniques are not mutually exclusive; oftentimes we need to use both chemical and physical preservation approaches together to provide the safest food products with the fewest additional ingredients and processes. Canned foods are a great example of the hybrid preservation approach.

To can food safely, one must ensure:

  • the food contents reach a specific acidity level; this usually requires the addition of a chemical such as ascorbic acid (Vitamin C) or salt.
  • the canning jar and lid are sterile; this involves boiling the jar or another physical sterilization process.
  • a completely sealed lid; this limits the oxygen needed for microbial organisms to live and prevents unwanted microbes from contaminating food, this typically requires the physical technique of heating the sealed jars.

A form of the above outlined thought process is applied across our food systems, so we get the highest quality, safest product with the fewest additions and preservation procedures.

Are preservatives safe to consume?

According to the U.S. FDA, all of the chemical and physical preservation techniques we currently use are safe for most individuals. As will all things in life, moderation is key when consuming foods and food products. 

Exclusively consuming high fat, high sugar products that contain preservatives will have negative long-term health consequences. However, we have not yet determined that these health impacts are related to the use of chemical preservatives within recommended quantities or are the consequences of an overall unhealthy lifestyle. Research is ongoing regarding specific preservative ingredients and their health impacts.
Researchers and the U.S. FDA take food safety seriously and strive to ensure all foods and food products are safe for everyone to consume. Thus, researchers work with food regulatory agencies to share essential preservative discoveries so agencies can modify preservation regulations and guidelines based on science.

What are common chemical preservatives?

Common antimicrobial preservatives used to reduce the microbial spoilage of foods by inhibiting the growth of bacteria, yeasts, and molds. Below you will find the ingredient and the products it typically preserves. 

  • sorbic acid, sodium sorbate, sorbates: cheese, wine, baked goods, and more
  • benzoic acid, sodium benzoate, benzoates: jams, salad dressing, juices, pickles, carbonated drinks, soy sauce, and more
  • sulfur dioxide, sulfites: fruits, wines, and more
  • nitrites, nitrates: meats
  • lactic acid: yogurt, kefir, cottage cheeses, and more
  • propionic acid, sodium propionate: baked goods, and more

Common antioxidants used to prevent oxidation. Below you will find the ingredient and the products it typically preserves.

  • ascorbic acid, sodium ascorbate: cheese, chips, and more
  • butylated hydroxytoluene, butylated hydroxyanisole: oils, packaging, and more
  • gallic acid, sodium gallate: wines and more
  • sulfur dioxide, sulfites: beverages, wines, and more
  • tocopherols (Vitamin E): oils, cereals, and more

Can I preserve foods safely at home?

Absolutely! Whether you are freezing, canning, smoking or doing other preservation processes, anyone can preserve foods safely if they follow all guidelines outlined by the USDA.

How does this help prevent food waste and increase food sustainability?

Our foods spoil and lose palatability quickly without preservatives. By using preservatives and preservation techniques responsibly, we can reduce food waste, increase food shelf-life, and help feed people with limited access to a safe, consistent food supply.
Next, in our 101 series, we will explore preservatives in cosmetics and household products.

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