Text B. CANNING

The canning of fruit and vegetables is very important as this food preservation process does not seriously injure the natural flavour of fresh food.

The first stage in the process consists of preparing the raw material by removing diseased fruit, and throwing away the waste portions such as stalks from plums, cherries or blackcurrents. Vegetables, carrots, potatoes are peeled and washed. Most of this work is done mechanically. Delicate fruits, such as strawberries and raspberries are prepared entirely by hand, and filled directly into the cans.

When fruits or vegetables are filled into the cans, brine is added to the cans of vegetables or syrup to the cans of fruit. The syrup is made by dissolving sugar in water, and sometimes a small amount of colouring matter is added.

The filled cans pass through a pre-heating process which removes any gases from the tissues of the fruit or vegetables. After heating during 5 to 12 minutes the cans are supplied with lids and hermetically sealed by a closing machine. They are then ready for sterilizing. Fruits, because of their high acidity, are easily sterilized in boiling water for 8 to 15 minutes. Vegetables, which have little acidity, cannot be sterilized at boiling point, and are heated for about 30 minutes under steam pressure at a temperature of 240°F. The sterilization is usually done in steel vessels holding about 1,000 cans.

After sterilization the cans are cooled down to a temperature of about 90°F. Then they are labelled by automatic machines which can label 150 cans a minute and are packed into fiber-board cases, either by hand or by automatic machinery.