Interesting:Ionising Radiation in Food Processing!!

Wow!!This topic seems quite interesting!!!Ionising Radiation in food processing and preseravtion???Ok let's get back to the good old chemistry books...Ionising Radiation includes Alpha rays,Beta rays and Gamma rays.The Gamma rays are the most penetrating of all the three so here in this article we will be dealing with ionisation by gamma rays.And this technique is currently gaining popularity in developing countries like India.Fulfilling the needs of about more than billion, with scanty resources is a no mean task for even for a developed nation. Increasing the productivity is aimed as one of the prime targets, effective utiliasation of the produce is yet another issue one needs to keep in mind while addressing the issue. It is noted that about 25 to 40% of food grains that is produced does not get consumed since they get spoiled before they reach the consumer.  The spoilage is essentially due to lack of processing of food grains, improper storage, and infestation by pests, fungal infection and also due to rodents.Oh Pests!!!

                                                     Now we get on to the most interesting at the same time boring part of food processing.Guess what it is???Oh ya it is the history of food processing.Food processing dates back to the prehistoric ages when crude processing incorporated slaughtering, various types of cooking, such as over fires, smoking, steaming, oven baking), fermenting, sun drying and preserving with salt. Foods preserved this way were a common part of warriors and sailor's diets up until the introduction of canned food. These crude processing techniques remained essentially the same until the advent of the industrial revolution. Growing demand for food, increasing storage losses of food grains and the existing limitations of the presently available method for processing have driven many researchers in the pursuit of devising novel techniques and methods which are not only safe, economical, proven and yet environment and eco-friendly.

                                                     Nicolas Appert developed a vacuum bottling process to supply troops in the French army with food, which would eventually lead to tinning and then canning by Peter Durand in 1810.  Pasteurization, discovered by Louis Pasteur in 1862 was a significant advance in ensuring micro-biological safety of food. But for him we would not be drinking our chocolate milks and other stuff!! In early 1900s scientist all over the world studied the use of ionising radiation for food processing applications. During World War II, the U.S. Army tested irradiation on fruits, vegetables, dairy products, and meat. NASA has routinely used irradiated food for several years.  Now the most interesting and amazing discovery was that the irradiation not only increased the shelf life of the food stuffs but it also abated the attack of rodents and pests!!!

 

Getting on to the process side ,Radiation processing of food involves exposure of food to short wave radiation energy to achieve a specific purpose such as extension of shelf-life, insect disinfestation and elimination of food borne pathogens and parasites. Now I can sense blood pressures shooting up as to these rays will not make the food radioactive and hence consumption lethal!!!The process cannot increase the normal radioactivity level of the food, regardless of how long the food is exposed to the radiation, or how much of an energy “dose” is absorbed. It can prevent the division of microorganisms, which cause food spoilage, such as bacteria and moulds, by changing their molecular structure. It can also slow down ripening or maturation of certain fruits and vegetables by modifying/altering the physiological processes of the plant tissues. GRAY is the unit of absorbed dose, which is equal to absorption of 1 joule of energy in kg of any substance. The effects that occur in the item irradiated would be proportional to the dose that is delivered.

                                                      Incidentally, the irradiation also kills several disease causing pathogens during the irradiation process. Among these, Escherichia coli O157:H7, Salmonella, Campylobacter jejuni, Listeria monocytogenes, and Vibrio are of primary concern from a public health standpoint because of the severity of the illnesses and/or because of the higher number of outbreaks and individual cases of food borne illness associated with these pathogens. With fresh poultry carcasses, irradiation up to a dose of 2.5 kGy will virtually eliminate Salmonella and Campylobacter under proper production conditions. The same dose of irradiation destroys E. coli O157:H7, a highly virulent bacteria which can lead to illness and death, and which is estimated to cause 20,000 infections and 250 deaths in the USA annually. Irradiation is currently the only known method to inactivate these pathogens in raw and frozen food. Infact irradiated food items are recommended for astronauts and cosmonauts during their mission in space and also to patients who require pathogen free food for consumption. Wow!!That sounds good!!!

                                                       Getting practical,like every other process this process also has limitations. Radiation processing is a need based technology and cannot be applied to all kinds of foods. Internationally only some of the major items that is being exported are cleared for irradiation. Many other items are undergoing extensive study world over. Another important factor to be borne in mind is that irradiation technique cannot make spoiled food a good one. This can be successful only if good manufacturing and packaging techniques are followed prior to subjecting them for irradiation. This technique is not a substitute for good manufacturing technique.

                                                      The results of food processing by irradiation have been reviewed by the experts of the World Health Organization (WHO), Food and Agricultural Organization (FAO), and International Atomic Energy Agency (IAEA) and also independently by the governments of various countries. The tests for wholesomeness and safety of radiation processed food include, checking for induced radioactivity, microbiological safety, safety of chemical changes, nutritional adequacy, and feeding studies on animals and humans. At the energies of the gamma rays from Cobalt-60 and those recommended for X-rays and accelerated electrons, no radioactivity can be induced in foods. Thus,it is inferred that this technique does not induce any radioactivity into the food stuff or does it  alter the normal radioactivity of the food stuff.

READ MORE:    http://www.mofpi.nic.in