Probably radiation has been transformed into a word with a negative connotation attached to it. The credit for this goes to the harmful radiations about which we read every day in the newspaper, exposure to which leads to cancer, tumors and what not.But are all the radiations harmful? With the development in the food sciences sector, the method of irradiation is now being used to preserve food. Let’s have a look what exactly Food irradiation is.
Use of irradiation as a preservation technique
What is Food Irradiation?
Food irradiation is a preservation technique used to reduce the spoilage, extend the shelf life of the product and even kill the pathogenic (disease causing) bacteria present in the food.
This is carried out with alpha, beta and gamma radiations. These are collectively called as ionizing radiations. The radiation dose applied to a food product is measured in terms of kilograys (kGy). The dose applied to a food depends on-
- Composition of the food
- Degree of perishability,
- The potential of the food to support harmful microorganisms.
Certain foods such as milk and eggs cannot be preserved by this method as it causes textural changes in them. But in general, irradiation causes minimal changes to the chemical composition of the food. However, a certain amount of reduction is observed in vitamin B complex vitamins.
How are these radiations produced??
Gamma rays are produced from radioisotopes cobalt-60 and cesium-137 . Both cobalt-60 and cesium-137 emit highly penetrating gamma rays that can be used to treat food in bulk or in its final packaging where presently Cobalt-60 is most extensively used.
Irradiation is also achieved from Electron beams and X-ray generated from machine sources. The high energy electron beams have limited penetration power and are suitable only for foods of relatively shallow depth.
X rays have more penetrating power than the gamma rays as well as X rays generation does not involve any radioactive substance but their use is still limited in the food industry. The primary reason for this is the lesser efficiency in the conversion of electrons to X rays.
Food Irradiation process
The process can be classified into the following types based on the dose of the radiations used-
- Radurisation i.e process of irradiation that leads to a substantial increase in the keeping quality of the food. This is done by using dose of 0.4- 1kGy.
- Radicidation i.e the process of irradiation that leads to reduction in the non spore forming microbes to such an extent that they are not detected by any recognized analytical method. This is also effective against parasites such as worms. The dose is in the range 2-8kGy.
- Radappertization i.e the process of irradiation that leads to reduction in the microbial to such an extent that they are not detected by any recognized analytical method, spoilage time increases and so does the shelf life. The dose is in the range 25-40kGy
Uses of Food irradiation
The process of irradiation has a number of advantages because of which it is considered as a preservation technique. Few of them are-
- Increases the shelf life of the food product
- Reduces the food spoilage and the risk of certain pathogenic( disease causing ) microorganisms
- It also reduces the risk of food pests which may be present inside the food items.
- Use of irradiation as a preservative technique reduces the use of chemical preservatives and antioxidants, few of which can be toxic
- It significantly delays sprouting in potatoes, onions, herbs and spices.
Acceptability of irradiated food
The constraint on the acceptability of irradiated food by people is mainly due to the belief that irradiated food becomes radioactive. Excessive testing and research has been carried out in this regard which shows that irradiated food is safe to consume.
People also fear that irradiation will remove or suppress the signs of spoilage like smell. Thus they would not be able to differentiate between fresh and stale food.
The foods that have been irradiated are to be labelled with the statement that the food, ingredients or components have been treated with ionising radiation. In addition to compulsory labelling, irradiated foods may also be marked with a symbol called a ‘radura’, which is the international symbol for irradiation.
In a nutshell
With the changes in the lifestyles, there is a great need for the changes in their mindsets too. Irradiation as a preservation technique poses to be a safe and reliable technique. Thus it must be accepted whole heartedly. It is far better and safer than all those pesticides and insecticides sprayed on our food which lead to lifelong problems. So do think about it.
Food Irradiation Video :