Preservatives

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.