Packaging

Packaging essentially means placing a commodity into a protective wrapper or container for transport or storage or both. Thus package must perform the following important functions.

• Contain the product
•  Protect the product
• Help in selling the product

 Concentrated milk is packed in suitable containers for storage and transport.Sweetened condensed milk is packed at the end of the manufacturing process.Evaporated milk is packed in containers immediately after concentration and then sterilized with the container. In case of Ultra High Temperature (UHT) treated milk, the product is sterilized and then aseptically packed in suitable containers.

i.                    Packaging of Condensed Milk

Two types of packages are used. For large quantity or for bulk transport, the condensed milk is filled in barrels of various sizes ranging from 50kg to 300 kg. The barrels are made either from wood or metal. Barrels are coated internally with wax or provided with polythene liners. Before condensed milk is run into barrels, they should be sterilized by means of steam, condensate allowed to drain and then filled by means of a funnel placed in the bunghole. When the barrels are full, the bungs are driven in, thus effectively, sealing the content. The room in which the barrels are filled should be in sanitary condition and its atmosphere should preferably be one of filtered air. Condensed milk is usually filled in barrels, at around 15.5°C (60°F).For retail sale the condensed milk is packed in cans of various sizes from 200 gms to 5 kg or even more. The method used for can filling varies from hand filling to continuous automated filling. In big factories tin sheets are shaped into cans by machines, which are then filled and sealed immediately. In small factories the cans are bought readymade and filled and sealed either manually or by machines. Sealing is carried either by means of solder or by crimping on the tops of the cans to form an airtight seal without the use of solder. The cans should be sealed immediately after they have been filled in order to prevent contamination of the product by exposure to atmosphere. Since cans filled with condensed milk do not undergo subsequent sterilization, strict sanitary conditions should be observed during filling process so as to prevent contamination which will otherwise affect the keeping quality of the stored product. The filling and sealing area should be enclosed and only filtered air should be circulated to avoid direct exposure to atmospheric dirt or dust during filling. The filling machines and accessories should be thoroughly washed and sanitized before start of the filling operation. The cans and lids on their passage to the filler should be suitably sterilized. This is usually done by passing the cans under or over a battery of suitable gas jets. Personnel operating the filling and sealing machines should observe sanitary habits. It is important to fill cans fully so as to exclude as much air from the container as possible and seal them promptly after filling.

ii.                  Packaging of Evaporated Milk

Several machines have been designed for this purpose. In one type, which is known as “Vent hole type” concentrated milk is filled through a small aperture (3 mm of 1/ 8 inch diameter). After cans have been filled they are immediately sealed. Sealing process requires care, as the seal has to with stand the heat of sterilization process.It is also essential that cans are filled as quickly as possible to avoid contamination of milk. The opening in the cans is usually soldered by mechanical finger. But hand soldering is also practiced while handling smaller number of cans. When the cans leave the sealing machine they are tested for leaks by being plunged into a hot water tank. If any of the tins rise or give off air bubbles, they are discarded as unfit for sterilization. Modern sealing processes are so rapidly carried out that a large number of cans may be sealed in one minute. In this process open or sanitary type cans are used. The concentrated milk is filled into the open can one end of which is already seamed and after filling the other end of the can is seamed by an automatic seaming machine.