Fruit canning

Food is preserved by using methods that destroy or hinder the growth of microorganisms, such as molds, yeast and bacteria. These organisms may be present in the soil, on the food, in the air, on equipment or on work surfaces.

Yeasts, molds and bacteria must be destroyed during processing to prevent the food from spoiling. The correct amount of time to process varies with the kind of food. Sufficient heat for a specified length of time kills microorganisms and insures a safe product.

Canning is a method of preserving food by first sealing it in air-tight jars, cans or pouches, and then heating it to a temperature that destroys contaminating microorganisms that can either be of health or spoilage concern because of the danger posed by several spore-forming thermo-resistant microorganisms, such as Clostridium botulinum (the causative agent of botulism).

Canning is also to retain nutrients and optimum quality, preserve fruits and vegetables when at their peak of freshness. All fruit preserved by canning should be heat-processed to attain commercial sterility.

Whereas vegetables and certain other foods require the application of high temperature (240°F, 250°F) or higher for significance lengths of time to attain commercial sterility, most fruits sufficiently acid (PH usually below 4.5) that commercial sterility can be attained by heating the containers in boiling water to the point where all parts of the product reach a temperature of 180°F – 200°F.

After heat sterilization, containers are quickly cooled to prevent overcooking. Containers may be 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.

Adding syrup to canned fruit helps to retain its flavor, color, and shape. It does not prevent spoilage of these foods.
Fruit canning

Processing of raspberries

Berries designed for processing are picked at a full to dark red stage, when fruit adhesion is minimal and machines can easily dislodge berries by using a shaking system. Fresh berries are transported directly from the grower or packer to the processor. Berries are washed and sorted to remove the deformed and overripe berries unfit for canning.

The berries should be shaken gently onto a wide white inspection belt, where inspectors will remove any foreign bodies such as calices, insects, leaf, twig and stones.

The berries should be clean and fee of rot or significant mold and posses typical color and flavor.

Raspberries are size graded using slat riddles. The berries are canned in heavy syrup (50-55 °Brix) foe dessert purpose or in water for use in pies.

Cans are exhausted until a center temperature of 18 ° C is reached.

For processing of puree, after washing the berries are either frozen in drums or totes for further processing or conveyed to a chopper or disintegrator.

After chopping, the berry is sieved or screened in a pulper/finisher to remove extraneours material (leaves, cap) and a homogenous puree is produced.

For seedless raspberry puree is produced using a screen of .045 in and screens of .060 or .125 in would be used for a raspberry puree with seeds.
Processing of raspberries