ASSESSING"FRESHNESS" OF PACKED FOODS-A NEW TECHNIQUE

It is the consumer psychology that the foods consumed by them must be as fresh as possible though health aspect also comes into reckoning with some segment of the consumers. The front of the pack label indicates when the product is manufactured and for how long the contents are good for eating. However this information does not guarantee that the food inside the unopened pack is still good, the consumer depending entirely on the label declaration to take the buying decision. Foods are packed in rigid as well as flexible containers and the packaging materials used can be metal, plastics, paper, laminates etc depending on the functionality and shelf life desired. While transparent packaging may provide some clue regarding the appearance of the product based on which some consumers decide whether they are good or bad, there is not sure way of arriving at a decision about the quality without opening the sealed pack. Recent news that scientists have come out with a a gadget that can "tell" whether the packed food is good for eating, is indeed a welcome news and it is worth evaluating the efficacy and relevance of the new gadget for the industry, retailer and consumer.

When a food is packed in any container the industry has a few options to extend the life of the product to some extent through manipulation of the gas composition inside. Most products are packed in plastic pouches and sealed under atmospheric condition. The head space with in the pack is air containing mostly about 21% oxygen, 78% Nitrogen, 1% Argon and some trace gases like Carbon Dioxide and others. It is the presence of Oxygen in the air which causes quality deterioration in food through oxidative chemical reactions and support for growth of microorganisms if the water activity in the product is conducive for them. Oxidation becomes a critical issue in dry products, especially if the concentration of oil component in the product is significantly high. Oxidative rancidity is one of the major problems for the fried product industry and there are many antioxidants deployed for retarding rancidity in such products. Vacuum packing and Nitrogen flushed packing are also employed to protect food from rancidity and consequent flavor deterioration. Use of modified atmosphere packing technology is based on controlling the composition of the gas inside a pack with predominance of CO2 which prevents growth of microorganisms, especially in high moisture products like fresh fruits and vegetables besides slowing down biological reactions to extend their effective life.  

A new laser technology developed in Sweden is claimed to be capable of detecting the gas composition inside packaged foods and determine the relative freshness of the content. Since It is a non-destructive method to test "freshness" of packaged foods, the developers feel that its utility would be of great relevance to all those involved in quality assessment of foods. Through measurements of the gas composition the product quality within can be monitored at different times effortlessly, enabling to check a much higher number of products than at present by the retailers as well as the industry. Most packaging practices use simple flexible pouches made from plastic films with varying gas permeability and oxygen is bound to seep in through the film surface into the pouch leading to oxidation, the growth of bacteria, and spoilage. The hand held instrument developed by the scientists is able to determines gas composition within food packaging using a laser spectroscopic technique which measures the absorption of light when the laser passes through the package and based on the signal, a computer provides the gas composition within. 

The only prerequisite for the technology to be successful is that light must pass through the package for measurement of the transmitted light and correlating to the gas composition. It appears almost all packaging materials currently in vogue allow at least some light to pass through making the method universally applicable. With the advent of lamination technology there are many permutations and combinations of films with Aluminum foil to control the gas and vapor transmission properties and the fact that even these packaging systems containing Aluminum foil can transmit light to the extent of as low as 0.001%, can make the laser technology relevant to almost all segments of food industry. Though technical soundness of the concept is well established beyond doubt there can be some challenges when commercial application becomes a reality.

A most critical question is whether the optical properties of the content inside can vitiate the result and if so to what extent. Similarly will there be variation from product to product and whether individual standardization will be required for each and every product. Ultimately who are the target users of this beautiful technology, whether the consumer, industry, quality monitoring agency or the retailer? Will there be a day in future when retail stores keep this instrument at each bay so that the consumers can check the products they want to buy for their freshness and if so how can the retailers avoid massive return of products left behind by the consumers to the manufacturers? Does this technology has a potential to disrupt the current food supply chain dynamics seriously? These are challenges that need to be addressed before mass deployment of this "toy"!

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com