2. Blood sausageLiver pate Corned beef in can

3. Fig: Basic canning process flow Selection of raw materials Preparation (eg cutting, dicing) Cooking of raw mat.Hot fill methodExhaustingSeaming Processing/ Sterilization CoolingStorage and labelling

4. Principles of food canning Aim of sterilization of meat products is the destruction of all contaminating bacteria including their spores. Heat treatment of such products must be intensive enough to inactivate/kill the most heat resistant bacterial microorganisms, which are the spores of Bacillus and Clostridium. In practice, the meat products filled in sealed containers are exposed to temperatures above 100°C in pressure cookers. Temperatures above 100°C, usually ranging from 110- 121°C depending on the type of product, must be reached inside the product. Products are kept for a defined period of time at temperature levels required for the sterilization, depending on type of product and size of container. If spores are not completely inactivated in canned goods, vegetative microorganisms will grow from the spores as soon as conditions are favourable again. In the case of heat treated processed meat, favourable conditions will exist when the heat treatment is completed and the products are stored under ambient temperatures. The surviving microorganisms can either spoil preserved meat products or produce toxins which cause food poisoning of consumers

5. Amongst the two groups of spore producing microorganisms Clostridium is more heat resistant than Bacillus. Temperatures of 110°C will kill most Bacillus spores within a short time. In the case of Clostridium temperatures of up to 121°C are needed to kill the spores within a relatively short time. The above sterilization temperatures are needed for short-term inactivation (within a few seconds) of spores of Bacillus or Clostridium. These spores can also be killed at slightly lower temperatures, but longer heat treatment periods must be applied in such cases to arrive at the same summary effect of heat treatment.

6. Exhausting Objective of exhausting;  to remove air so that the pressure inside the container following heat treatment and cooling will be less than atmospheric. Functions The reduced internal pressure (vacuum) helps to keep the can ends drawn in reduces strain on the containers during processing minimizes the level of oxygen remaining in the headspace. to extend the shelf life of food products and prevents bulging of the container at high altitudes. Vacuum in the can may be obtained by the use of heat or by mechanical means. The products may be preheated before filling and sealed hot.

7. Hot fill method Hot-fill-hold processing involves filling the product hot sealing the container holding filled containers for a period of time at or above a certain temperature before cooling. Acidified products may also be processed in a pasteurizer, atmospheric cooker or retort for a given period of time to destroy the target microorganisms

8. Sealing In sealing lids on metal cans, a double seam is created by interlocking the curl of the lid and flange of the can. Many closing machines are equipped to create vacuum in the headspace either mechanically or by steam-flow before lids are sealed. Double seaming of can

9. Heat Sterilization During processing, microorganisms that can cause spoilage are destroyed by heat. The temperature and processing time vary with the nature of the product and the size of the container. Effective combination commonly used for small consumer sized products (4-8 oz) is 3 minutes at 121 o C Acidic products, such as tomatoes, are readily preserved at 100°C (212°F). The containers holding these products are processed in atmospheric steam or hot-water cookers.

10. Cooling After heat sterilization, containers are quickly cooled to prevent overcooking. Containers maybe quick cooled by adding water to the cooker under air pressure or by conveying the containers from the cooker to a rotary cooler equipped with a cold- water spray. Labeling And Casing After the heat sterilization, cooling, and drying operations, the containers are ready forlabeling. Labeling machines apply glue and labels in one high-speed operation. The labeled cans or jars are the packed into shipping cartons