India is the only country where numerous packing materials are available, traditional as well as modern. Used news papers and magazines, plantain leaves, colacasia leaves, teak wood leaves and many other leafy materials are used by groceries and take away food vendors. Fresh meat is invariably wrapped in locally available leaves though lately plastic films and carry bags are replacing them in many places. Stitched leaves from perennial trees like teak, tendu etc are also used in some parts of the country for wrapping foods. The leaf cup making cups, designed by CFTRI in nineteen eighties, are mechanically being produced from arecanut sheath, dry banana leaves, etc and find favor with many consumers. Combinations of leaves, paper and polyethylene, give better packing material with water-proof properties.
Modern packaging materials used widely by today's food processing industry include metal cans and tins of different shapes, glass bottles, rigid and flexible plastics, laminates of different types, paper bags, cartons and corrugated boxes. While large sized metal tins are routinely used for packing many food materials like edible oils, cashew nuts, biscuits etc, Open top Sanitary cans and tagger top cans, fabricated from tin coated steel sheets and aluminum sheets find extensive use for many processed foods and beverages. There are specially designed machinery that can accomplish tasks like filling, evacuation, gas flushing and closing for almost all modern packaging materials. Form-Fill-Seal machines are in wide use for packing liquid as well as free flowing solid food materials. Aseptic packaging system, involving filling of pre-sterilized liquid products, has been widely adopted for milk, beverages and many other popular fluid foods. As most of the flexible packaging materials cannot stand high temperatures of food sterilization, products have to be pre-sterilized before filling and packed under hygienic conditions for good shelf-life. There are special laminates with polyester with or without Aluminum that go for packing of retortable foods which have found a prominent place in the Indian Market.
The packaging industry and the food industry are supposed to be complimentary with the former tuning its ears to the requirements of the latter. Unfortunately in many cases such synergy is conspicuous by its absence and food industry has to be satisfied by what is "offered" by the packaging industry. Spoilage that originates from the packaging materials used by processors is never recognized. Invariably many small scale processors do not even sanitize the packaging materials before use for packing their food products and the cross contamination can cause spoilage of the contents in many cases. It is not known how many packaging material suppliers sanitize their products before dispatching to the processors. There are well defined chemical and physical specifications for food packing materials, be it cans or bottles or synthetic products but rarely one comes across the third dimension in packing, which is the microbiological status of the supplies that are received by the processor. It is understandable that all these packaging materials undergo thermal processing during manufacture and therefore can be assumed to be free from microbes. But the storage and transportation environment can cause serious cross contamination of the surface which is rarely recognized.
Ultraviolet(UV) disinfection technology, which is basically a surface treatment technique is excellently suited for sanitizing packaging materials used for foods, Widely used by the water industry for bottling of water as well as bulk supply and distribution of water for potable purpose, UV-C in the wave length region of 100-280 nm has been found to be most effective in killing microorganisms such as bacteria, mold, yeast and viruses. UV disinfection equipment, currently available are designed mainly for free flowing fluids like water but can be suitably modified to surface sterilize packaging materials in the form of sheets before fabrication into containers or pouches. Dosage in the range of 0.4 to 30 nm/cm2 can achieve total kill of all bacteria and enteroviruses. UV rays affect many chemicals present in the microbial cell including its DNA virtually making it inactive any more. Such types of equipment must be a part of the packing ,material manufacturing systems and once treated they must be hermetically sealed to prevent cross infection during further handling. Alternatively, processors should have these facilities, especially for flexible packaging materials which cannot be washed or sterilized before filling like cans.
The manufacturers of traditional packing materials also must be sensitized regarding the need for sanitizing their products before retailing in the market. Small scale devices at affordable price is the need of the hour and appropriate procedures will have to be worked out for these entrepreneurs who must be persuaded to stream line their production and delivery mode so that their materials are safe for food contact application, including packing of solid as well as liquid foods.