Students may arrange to tour a food-processing plant in their area. Such a visit can be a good way to get a general overview of the jobs in the plant. Talking to people employed in different jobs in canning or preserving plants is another good way to learn something about the field. Because some food-processing work is seasonal, part-time job opportunities for students may be limited. However, temporary employment, such as during summer harvest season, may be possible.

In order to operate successfully, a food-processing plant must have plenty of the foodstuff it processes. Therefore, many workers in the canning and preserving industry work outside processing plants arranging for this supply of raw materials. Field contractors negotiate with farmers to grow certain kinds of food crops for processing. They work with farmers to decide what to plant, how to grow the crop, and when to harvest it. They reach agreements concerning price, the quantity that will be delivered, and the quality standards that the crop must meet. Purchasing agents purchase raw materials and other goods for processing.

When unprocessed food arrives at the factory, graders, including fruit-buying graders, examine produce and record its quality, or grade, and mark it for separation by class, size, color, and condition.

Wharf laborers unload catches of fish for processing from the wharf and transport the fish to the processing plants storage area. Fish-bin tenders sort fish according to species and size.

At the plant, the plant superintendent coordinates processing activities to coincide with crop harvesting. The plant manager hires workers, contacts buyers, and coordinates maintenance and operation of plant machinery.

Most processing of food is done with automatic machines. Dumping-machine operators run machines that grip, tilt, and dump boxes of produce onto conveyor belts leading to washing vats. Workers then wash food and inspect the produce, removing damaged or spoiled items before they can be processed. Sieve-grader tenders and sorting-machine operators tend machines that sort vegetables, shrimp, and pickles according to size.

Many foods are bathed in brine, a concentrated solution of salt in water that acts as a preservative. Brine makers measure ingredients for the solution and boil it in a steam cooker for a specified amount of time. They test the solutions salinity with a hydrometer and pump it to a processing vat. They may also operate the vats and empty and clean them when necessary.

Plants that process fish and shellfish may kill, shell, and clean the fish before processing. Crab butchers butcher live crabs before canning. Fish cleaners and fish-cleaning-machine operators scale, slice open, and eviscerate fish. Using a shucking knife, shellfish shuckers pry open oyster, clam, and scallop shells and remove the meat. Shrimp are often shelled by machines that are operated by workers who must make adjustments according to the size of the shrimp. Later, separator operators remove any sand or remaining shell particles from shellfish meats using water or air-agitating machines. Alternatively, bone pickers look for shell particles by placing shellfish meats under ultraviolet light and picking shell bits out by hand. Other workers operate machines that wash, steam, brine, and peel shellfish.

Often only one part of a fruit or vegetable is wanted for processing. Many workers operate machines that peel or extract the desired parts from produce. Finisher operators run machines that remove the skin and seeds from tomatoes, leaving pulp that is used in sauces and catsup. Lye-peel operators run machines that use lye and water to remove skins of fruits and vegetables. Fruit-press operators run power presses to extract juice from fruit for flavorings and syrup, and extractor-machine operators extract juice from citrus fruits.

Food must often be cut into pieces of the proper size and shape for preserving. Meat blenders grind meat for use in baby food. Many workers operate machines that cut or chop produce, and fish butchers and fish choppers cut fish into pieces and lengths for freezing or canning.

Next, foods are cooked. Some are cooked before and others after they are sealed in packages. Many vegetables are blanched (scalded with hot water or steam) before packaging, by blanching-machine operators. Kettle cooks and kettle cook helpers cook other fish, fruits, and vegetables in large kettles before packaging. These workers must measure and load water and uncooked food into the kettles; stir, monitor, and test foods as they cook; and remove cooked food from the kettles. Other workers cook fish, meat, and vegetables by deep-frying before freezing. Vacuum-kettle cooks vacuum-cook fruits and berries for jam and jelly.

Other foods, including many vegetables, are processed after they have been sealed in cans. Packers fill cans or jars with food to specified volume and weight. Other workers operate closing machines to put an airtight seal on the containers. Containers are then taken to retort chambers. Retorts are like huge steam pressure cookers, and they can heat food containers to temperatures between 240 degrees Fahrenheit and 260 degrees Fahrenheit. Retort operators load, start, and stop these machines according to specifications. Food must then be quickly cooled to stop cooking. Pasteurizers kill bacteria in bottles, canned foods, and beverages using a hot water spray or steam. Some food is preserved using brine. Picklers mix ingredients for pickling vegetables, fruits, fish, and meat and soak these foods for a specified period of time. Briners immerse fresh fish fillets in brine to condition them for freezing.

Some food is prepared for canning by removing moisture, and some fish is smoked to preserve it. Fish smokers put salt-cured fish on racks in a smoke chamber and turn a valve to admit smoke into the chamber.

Many foods are frozen fresh or after blanching. Freezing-room workers move racks of packaged food in and out of freezing rooms. They keep track of the amount of time food has been in the freezing room and remove the food when it is sufficiently frozen to transport to a warehouse or onto delivery trucks. Freezer-tunnel operators quick-freeze foods.

Other foods, especially fruits, are preserved by drying. Dehydrator tenders bleach and dehydrate fruit, while other workers dry eggs, milk, and potatoes.

Once food has been canned, it is labeled, tested, and inspected. Vacuum testers tap can lids to make sure they are vacuum sealed. Can inspectors check seams of closed food and beverage cans by cutting and taking measurements of seams of sample cans. X-ray inspectors examine X-ray jars of baby food to ensure they contain no foreign materials.

Other workers clean cooking kettles and other equipment. Production helpers perform a variety of unskilled tasks in canning and preserving plants. Workers may also be designated according to the food they prepare: steak sauce makers, mincemeat makers, relish blenders, and horseradish makers, for example.

Cook room supervisors and preparation supervisors monitor and coordinate the activities of workers in preparing and canning foods. Fish-processing supervisors train new workers and inspect fish.

In large plants, each worker may perform one specific task. In smaller plants, one worker may perform many of the tasks necessary to preserve the food.