Canned packaging is generally printed using Lithographic Printing Method (Offset) or better known as Offset metal decorating. Printed in Tin, Aluminum, and alloy metal modifications. The metal material will be coated in advance ( coating ) with Varnish saizing ( clear sizing , tonner sizing or gold lacquer ) or to get white effect in white Coating. All coating methods are commonly used in coating machines ( Coater ) with thicknesses measured in μm.
After the coated metal coating Varnish sizing or White Coating Then it will be heated between 170-180 0 C for 12-15 minutes past the giant toaster spaced 5-6 meters. After passing the toaster the material has dried and ready to print with offset / Lithography ink. Color-drawing process images (Cyan, Magenta, Yellow, and Black usually go up 2 colors then 2 next colors.
The process of drying offset inks is also via a grill with temperatures ranging from 140-160 ° C for 12-15 minutes. Then the final process of the ink layer will be coated with Varnish to make the mold scratch resistant and heat resistant. For other parts which will be part in the packaging surface of the cans will be coated also with varnish coating with the aim of preventing direct contact with the product kelang so it can lead to rust and contaminated. After all the printed surface and the varnish of the tin will be continued to the testing process to determine the strength of the packaging so as to prevent damage to the packaging that resulted in damaging the product. Other tests are Retort test and Pasteurization (Anonimous, 2010).
Canning is defined as a popular way of preserving foodstuffs (impermeable to air, water, microbes, and other foreign substances) in a container, which is commercially sterilized to kill all popular microbes (cause of disease) and decay. Cannery popularly allows food to be avoided and rotten, changes in water content, oxidative damage, or taste changes .
The main advantage of using cans as foodstuff containers is that cans keep food ingredients in them. Food contained in hermetically covered containers may be guarded against contamination by microbes, insects, or other foreign materials that may cause decay or deviation of appearance and taste.
Cans can also keep food on unwanted water content changes. Cans can keep food on the absorption of oxygen, other gases, odors, and radioactive particles in the atmosphere. For color foods that are sensitive to photochemical reactions, cans can guard against light.
Among the bacteria associated with canning fish, Clostridium botulinum is the most dangerous. The bacteria can produce botulin toxins and form heat-resistant spores. Heating for four minutes at a temperature of 120 degrees C or 10 minutes at a temperature of 115 degrees C is enough to kill all C. botulinum strains (AC). Because of its heat resistance, if the canning process is done incorrectly, the bacteria can reactivate during storage.
In the process is usually done addition of canning medium. In Indonesia, there are three kinds of canning medium, namely salt solution (brine), oil or oil which is added with chilli and other spices, and tomato sauce. The addition of medium aims to provide a specific appearance and taste in the final product, as a medium of heat introduction, thus shortening processing time, obtaining higher acidity, and reducing rust on the inside of the can. If you want a ready-made product, choose a tomato ketchup.