One of today’s challenges for the food industry is to guarantee safe foods throughout the supply chain, whilst retaining the same properties that were present when the foods were freshly made. During the distribution channel, from food manufacturer to consumer, food products need to be protected against physical, chemical and microbial deterioration. “Preservatives” focus on the prevention of food spoilage, caused by the activity of micro-organisms.

Cranberry and orange juices in mason jars

Different types of preservatives

Preservatives are food additives used to keep food safe for consumption and extend shelf life by preventing spoilage. The most common preservatives are:

  • Benzoic acid
  • Sorbic acid
  • Propionic acid

Benzoic acid and benzoates are broad spectrum preservatives active against bacteria, yeasts and moulds. They are most effective in acidic products. The most common used form is sodium benzoate. Potassium benzoate can be used when sodium reduction is an issue.

Sorbic acid and sorbates are most effective against yeasts and moulds and are effective in acidic to neutral conditions. Potassium sorbate is the most widely used form.

Propionic acid and propionates are effective against moulds and can be used in acidic to neutral products. Calcium propionate is mostly used.

Flax seed and ingredients for granola bar

Functionality of preservatives

The so-called hurdle technology in preservations, means putting up different hurdles or different means of preventing microbial activity and multiplication.

The first hurdle is the temperature during processing or storage. A heat treatment is often used to extend the shelf life of foods. Depending on the temperature / time combination applied, part or all micro-organisms are destroyed or inactivated, this starts at temperatures above 60°C. Decreasing temperatures also reduce the activity of micro-organisms and enzymes. In the refrigerator and in the freezer, micro-organisms are less active or completely inactive, but they are not destroyed. Secondly, the presence of air/oxygen can be influenced. By carefully choosing the packaging material and packaging process, such as vacuum packaging or modified atmosphere packaging, oxygen as a growth factor can be removed. And thirdly the food composition itself creates a relatively attractive environment for micro-organisms and makes the food more or less susceptible for food spoilage.

Water is essential for micro-organisms and therefore drying is an effective method of preservation. Also, the addition of high salt levels and addition of high sugar levels, are based on reducing the water that is available for the micro-organisms. Preservation, by influencing the acidity level (pH), is undertaken through the addition of organic acids, e.g. pickling in vinegar. And last but not least, chemical preservatives can be added to reduce or inhibit the activity of the micro-organisms.

The approach of combining multiple food hurdles in food processing, food packaging and food composition is most effective and will result in lower dosages of preservatives being required.

Clean label

Consumers are demanding labels with ingredients they recognise and understand. As "no preservatives" is amongst the most popular clean label claims, food ingredient manufacturers have developed new ingredients to meet this demand. Several solutions based on fermentation technology are offered in the market.

Read our Guide to Clean Labels

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