Processing of canned fish

The canning of fishery products may be divided into a number of definite steps applying equally well to all types, although details of methods and processes vary with the individual product.

Defrosting
If frozen fish are to be processed, they must first be defrosted. The thawing process involves the elevation of temperature of the fish to 0 °C, at which temperature it may be manually cut or otherwise prepared as necessary.

Butchering
The splitting and evisceration process is normally the only butchering operation performed on the tuna while it is in the raw condition. This operation involves the scaling, evisceration, removal of parts not to be canned, and thorough washing in either salt or fresh water. The scaling may be done by hand with serrated-edge scrapers, the edges of knives or other means devised by the technician.

Salmon is traditionally filled into cans in the raw state. After grading, fish are fed into an iron chink butchering machine for the automatic removal of head, fins and viscera.

Pre-cooking
Sardines, mackerels and tuna are normally pre-cooked prior to sterilization. The object of pre-cooking, particularly in the case of tuna, is to facilitate the removal of flesh from the carcass.

Typically, sardines are packed into quarter club cans, which are placed in square plastic trays. The trays may hold some 4 x 7 cans each. A thin sheet of metal is placed over the tray and the whole inverted and placed on racks on a trolley which is then wheeled into a batch pre-cooker.

Functions of pre-cooking:
• Firm texture of fish
• Reduction in bacterial load
• Inhibition of enzymatic reaction
• Shrinkage for better filling
• Removal of cellular gases

The time for pre-cooking in steam at a temperature of 105 °C is about 30 minutes depending on the size of the fish.

Can filling
Before being canned, the cans and jars are rinsed with water under pressure of steam before being filled.

Filling may be accomplished either by hand or by machine. Can filling in large tuna factories is undertaken by high-speed machinery. The tuna is formed into a tube within the machine and sliced to the correct height and fill weight on presentation to the can. Smaller fish and meat scraps are generally canned as flakes after being pressed into moulds.

Sardines are traditionally filled manually into cans prior to pre-cooking, but automatic machines are also available.

Mackerel are processed in both rectangular and cylindrical cans and the filling operation may take place manually or by suitable machinery according to the size of the operation.

Covering liquid, oil, brine or sauce is added to fish within shallow cans to overflowing. The excess liquid is screened and returned to the filling head.

Fish and the liquid added to the can should be packed tightly to prevent it from shaking around and braking up into undesirable looking pieces, requires the fish to be packed in an orderly fashion.

The weight is checked at this point to prevent excessive filling that could lead to the foodstuff not being processed appropriately, swelling of the tin or even bursting of the seams.

The can may then be closed using steam flow to remove air and provide a vacuum within the can. Then the can is sealed. The sealed cans are cleaned to eliminate any remarks of filter and they are prepared for sterilization.

Heat Processing
Fish products and other low-acid foods are usually processed in steam at temperatures of 115° to 120°F. This operation is usually carried out in heavy metal airtight receptacles (retort) that will stand internal pressures of 20 and 30 pounds or more to the square inch.

Can coding
Coding may be applied to the ends of cans by use of embossing machines, or more frequently nowadays, by the use of ink jet machines.

Processing of canned fish

Banana – process of canning

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).

Banana cannot be canned on their own. The more important canned banana products are puree, baby foods, banana slices, and tropical fruit cocktail. Bananas are also canned as pastes, drinks and slices.

Banana can be canned in slices in syrup. Best quality slices are obtainable from fruit at early fruit at an early stage of ripeness. The slices are process in a syrup of 25° Brix with pH of about 4.2 and in some process calcium chloride (o.2%) or calcium lactate (0.5%) are added as firming agent.

Internally lacquered cans with an acid-resisting lacquer and a high internal tin coating mass is recommend as considerable corrosion has been encountered in plain cans.

When canning banana puree, the puree is filled into 30-lb cans with plastic film bag liners, sealed, and stored (2–4◦C). A process to do away with the acidification step involved extruding ripened, chopped bananas, heating to 121◦C by injecting steam, cooling to 2-3◦ C, filling into fiber containers and blast freezing (-20◦ C).
Banana – process of canning 

Canning of apple slices

Apples for processing should be sound, mature, reasonable size, and of uniform shape to be peeled. Apples for canned slices must be firm, maintain integrity of the flesh when sliced, and have good color. York, Stayman, Golden Delicious, Northern Spy, Rhode Island Greening, Yellow Newtown, and Jonathan are preferred for making slices.

The stem tips were removed and fruits immersed in chlorinated water (300 ppm) for 20 min. Fruits were either subjected to hand peeling, steam peeling or lye peeling. In steam peeling, the fruits were exposed to live steam at 100 °C for 6-8 min. Fruits were also soaked in either 5 or 10% lye solution for 30-60s at 28-3 °C.

The slicing operation is usually an integral part of the peeling and coring process where the apples are sliced into 12 to 16 pieces in the coring section. After slicing, the apples are inspected for defects such as blossom or calyx, carpel tissue, skin, and bruises and are conveyed over a shaker screen to remove small chips. Apple slice texture is very important. Therefore, apples with firm flesh and high quality are desired. Consistency of slice size can be controlled by using fruit from within a preselected size range.

Adding syrup to canned fruit helps retain its flavor, color and shape. It does not prevent spoilage of these foods. By using syrups offer a new “very light” syrup, which approximates the natural sugar content of many fruits.

In canning regular fruits without sugar, selecting fully ripe but firm fruits of the best quality is very important. Prepare these as for hot-packs but use water or regular unsweetened fruit juices instead of sugar syrup. Juice made from the fruit being canned is best. Blends of unsweetened apple, pineapple and white grape juice also are good for filling over solid fruit pieces.

The canned apples must be processed immediately after closing to a can center temperature of 82.2°C; there are several types of sterilizers available, Batch retort vessels, and continuous rotary cookers that operate either at atmospheric or pressurized conditions. Immediately after sterilizing, the cans should be cooled at 37 to 40°C to prevent “stack burn” or loss of product color in storage.
Canning of apple slices

Extension of shelf-life by thermal processing

The various forms of microbiological spoilage are preventable to a large degree by a wide range of preservation techniques, most of which act by preventing or inhibiting microbial growth.

Canning involves packing a food in a container and supplying sufficient heat treatment to kill spoilage organisms or pathogens that may present. It is a method of preserving where food is placed in airtight, vacuum-sealed containers and heat processed at 121 °C.

Thermal processing like canning process is a suitable method to prolong the shelf life of fruits, such as date fruit, which has some benefits, including: artificial maturation, destroying insects, reducing the microbial load, inactivation of enzymes (e.g. pectinase), and reducing tannin.

Commercial canning is done under tightly controlled conditions — careful sanitation and the necessary time and temperature under pressure, but there are still limits to how long it will preserve food. There are several factors that limit the shelf life of canned foods. First, cans can rust over time. Shipping accidents, where cans fall and dent or are crushed, also cause container problems.

Heat preservation (canning) provides a shelf-stable product, but usually at the cost of colour, flavour, and texture. Heat treatment, however, leads to destruction of freshness and nutrient losses.
Extension of shelf-life by thermal processing 

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

Canning of lima beans

The lima bean is a green or light flat bean. It is use only for the seed, the pods being coarse or woody. Some lima beans are canned and they are handled in such the same manner as the frozen product except that they may or may not be passed through the quality grader.

In case it is the fresh beans, the beans are first washed carefully and stored. They are size-graded and then blanched in hot water at 88-95 °C – the amount of time depends upon the maturity of beans, varying from 2 to 3 minutes for young, tender beans to 7 or 8 minutes for more mature tougher beans.

The beans are automatically metered into cans. The filled cans pass to the briner where a boiling hot 2% salt brine is added to completely fill the can. The cans are sealed and heat-processed.

Some lima beans to be canned are allowed to mature and dry out on the vine before harvesting. In such cases, the beans must be soaked in water for purposes of rehydrating prior to further processing.
Canning of lima beans

Blueberries in can

Blueberries can be canned, mainly used for pie fillings, are cleaned and inspected, placed in cans, and the cans are then filled with water or with a 10-30% sugar solution.

Canned blueberries can be light or heavy syrup packed or water packed. For this fresh or frozen blueberries are place in cans, light syrup or water is added to cover the head space and can are sealed and heat processed at about 93-95 C q-with 25-30° C minute holding time.

Canned blueberry pie filling, in which the berries are cooked, sweetened and packed in a thickened liquid are very popular in the United States and Great Britain. Canned blueberries may vary from a highly attractive free-flowing product to one is clumped into a firm mass. Clumping can be greatly reduced by cooling with agitation, which apparently interfered with the bonding together of berries by surface wax or cutin.
Blueberries in can

Canning process of raspberries

Raspberries are an important commercial fruit crop, widely grown in all temperate regions of the world. The raspberry is the edible fruit of a multitude of plant species in the genus Rubus. Red and black raspberries are canned by the same methods.

Raspberries should be picked when they are ripe but firm. The raspberries are then conveyed to the factory in crates of the shallow boxes to prevent bruising or crushing of the fruit.

Raspberries, like most berries, require considerable hand labor in preparing for canning. Berries are washed and sorted to remove the deformed and overripe berries unfit for canning. Raspberries are size graded using slat riddled.

The berries are placed in cans as they are washed, the filled can inverted to drain off the excess water, and the cans generally placed on a belt or some other type of filled can conveyor to carry them to the syruper.

The berries are canned in heavy syrup (50°-55° Brix) for dessert purpose, or in water for use in pies. If syrup is used, it should be added at a temperatue of at least 93 ° C. Some canners believe that the use of syrup that is too hot causes shrinkage of the berries.

Cans are exhausted until a center temperature of 18 °C is reached. This requires approximately 5-6 min at 100 °C.
Canning process of raspberries

Canning of strawberry fruit

The steps in canning strawberry are the following:
Strawberries for canning purposes should be firm in texture, of good color and flavour and of large size

Strawberries left alone for a couple of hours with sugar added to them will create their own syrup. An important item in canning the strawberry is to have them thoroughly heated before putting in cans, and the sooner they are sealed after being sufficiently heated the better they retain their color and flavor.

Prepare heavy syrup of 50° Brix. Fairly heavy syrup is necessary to develop and retain the berry flavor

Fill canning jars with berries within 1/2 inch of the top. Add just enough syrup to cover the berries. Place any remaining syrup in its own canning jar and fill to the same level

Strawberries are not suitable as fruit preserve in syrup than as canned fruit. When preserving strawberries in syrup, a glass jar is more convenient.
Canning of strawberry fruit

Green pigments in green vegetables

Green vegetables contain the green pigment chlorophyll which plays a key role in transferring light energy to chemical energy during growth and development of the plant by the prices of photosynthesis. Examples of such green vegetables include spinach, peas, beans, cabbage lettuce and celery.

Although chlorophyll does not appear to be useful in human physiology, foods that are high in chlorophyl are usually also high in B-carotene.

There are two types of chlorophyll and each produces a specific colour in green plants. Chlorophyll A is blue-green, whereas the more common chlorophyl B is green. Their chemical compounds differ in colour because of their different structures - chlorophyl a has a methyl group (-CH2) attached to one of the carbons on the chlorophyl molecule, whereas chlorophyl B has an aldehyde group (-CHO). Destruction of chlorophyl increases with cooking time.

Chlorophyll A is more readily converted to pheophytin than chlorophyll B. Green vegetables should be cooked for a very short time, less than minuets to retain the colour. Vegetables like peas, beans, greens are sometimes canned.

During canning chlorophyl gets converted to pheophytin due to the high temperatures used. Sometimes for stain the colour and to neutralise the acid, alkali is added.
Green pigments in green vegetables

Canned pineapple processing

Four cultivars account for the majority of pineapples used for canning: Cayenne, Singapore, Queen and Red Spanish.

Good-quality canned fruit is only attained when the fruit is just ripe, and every step is taken to process with least possible delay.

Harvested pineapples are unloaded from bulk bins at the cannery and, each pineapple is washed and graded for size to determine where the fruit will be sent.

The pineapple is then sent through a Ginaca machine that has been adjusted for a proper fruit size. This machine is entirely automatic and removes the inedible portion of the fruit from the edible parts.  This machine removes the shell, cores the fruit, and trims about 1.3 cm of the bottom and 1.9 cm at the top, greatly simplifying these operations. The final operation of the Ginaca machine removes the core from the centre of the fruit.

The rest of the pineapple is sent to be crushed into juiced and/or processed into livestock feed. Meanwhile, the fruit cylinder is inspected and hand trimmed to remove any defects or eyes, which may have escaped the first operation.

The fruit is then cut into slices, chunks, tidbits or crushed pieces or is pressed onto juice depending on its processing line destination.

Pineapple slices are usually graded and manually packed in cans. Sugar s added to the final product, which ensures certain homogeneity. Slices that have been cut either too thick or too thin, and broken pieces not good enough for canning as slices, are used in crushed pineapple or juice.

The cans are then sealed and cooked at 211 ° F for 11 minutes in a pasteurization process.

Notes:
*Slices or spiral slices or whole slices or rings: uniformly cut circular slices or rings cut across the axis of the peeled, cored pineapple cylinders.

*Tidbits: reasonably uniform, wedge-shaped sectors cut from slices or portion thereof, predominantly from 8 to 13 mm thick.

*Chunks: short, thick pieces cut from thick slices and/or form peeled cored pineapple and predominantly more than 12 mm in both thickness and width, and less than 38 mm in length.

*Ginaca machine is named after the man who invented it.
Canned pineapple processing

Can lining lacquer

Various lacquers have been developed for lining cans, especially for preventing food discoloration that could occur as a result of interactions between the food and the can.

Internal coating eliminates the food-metal interaction during storage while the external protects the can from abrasion and corrosion.

Three-piece food cans are made from lacquered tinsheets. The lacquer is roller-coated the sheet at a rate of 3000 – 5000 sheet per hour.

The cured lacquer shows a film thickness of 3-6 microns – in other words a very thin film.

It also aids in forming of cup and provides base for decoration.

Can lining lacquer

Vegetable processing

It is necessary to process green vegetables to preserve them for a year-round food source.  The most common commercial method of preservation is canning.  Canning is regarded to be a universal and economical method in food processing.

The principles of canning were first enunciated by Nicholas Appert in 1810, after many years of experiment and are essentially unchanged. For this process, the vegetables are cleaned, grading, heat blanching, peeling and coring, cut, packed into cans, sealed and heated to sufficiently high temperature (in the order of 240 ° F) to destroy spoilage and disease causing microorganisms. It follows by cooling, labeling and packing.

It is important for the food processor to control pH of the water added to the vegetable prior to canning. The vegetable may be canned whole, diced, pureed as juice and so on.

Vegetables are usually packed in liquid. Canner’s brine, a weak solution of sugar and salt, is ordinarily used for vegetables.
Vegetable processing

Raspberries fruit processing

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.
Raspberries fruit processing

Process and uses of canned blueberries

Fresh ripe blueberries may spoil of left out at room temperature for a day or more, but they will keep for 2 or 3 days if stored without washing in a covered container in the refrigerator. Canned blueberries can be light or heavy syrup packed or water packed.

Blueberries can be canned, mostly used for pie fillings, are cleaned and inspected, placed in cans, and the cans are then filled with water or with a 10-30% sugar solution to cover the head space.

The open cans are the exhausted or heated in free-flowing steam for 10 minutes, and finally sealed and heat process at about 93-95 °C with 25-30 minutes holding time.

The packing syrup from canned or frozen berries usually has picked up much of the color and flavor form the fruit. Hence, it may be used as a flavoring or a syrup for ice-cream sodas and sundaes, milk shake, mixed drinks, pancakes and waffles.

Compared with other fruits, canned blueberries are an excellent source of iron, fair sources of vitamin A, about average in protein fat and calcium and low in phosphorus.

Canned blueberries packed in water are low in calories and carbohydrates because they contain only about two-thirds the levels of the nutrients that are supplied by the raw fruit.
Process and uses of canned blueberries

Processing of green and wax beans

At the processing plant, beans are sorted out for size, washed and their ends are snipped off mechanically. They are then cut transversely or longitudinal and blanched.

Some beans are frozen individually and placed in plastic pouches alone or as a component of mixed vegetables or they may be first packaged and then frozen in a blast freezer. Some beans are canned in brine and processed.

Canning and freezing are the two most commonly used commercial methods of processing the beans. Other products such as purees for the beans are marketed as baby foods or specialty applications.
Processing of green and wax beans

Hermetically sealed metal containers

The preservations of canned products require hermetically sealed cans.  Presently three types of hermetically sealed containers are recognized by the food industry:
*Rigid
*Semirigid
*Flexible containers

By the early 1900s, the manufacturing and sealing cans were accomplished by machine. The technique was developed by Peter Durand, who used tin coated iron containers in place of glass jars. He was granted a patent in 1810 for his technique of preserving foods in hermetically sealad tin cans.

Double seam made by five layers compressed 

The lid used for the cans contained a rim to which a plastic casket could be added, and rim to could be sealed tightly by machine by first crimping it over and under the flanged top of the can body and then pressing the two together by a second roller operation.

The plastic gasket made the can airtight by filling the tiny voids produced between the rim of the cover and the flange of the cans as they were brought together.  The process of creating an airtight closure by attaching the can end component to the can body is called double seaming.

This double seem is a metal-to-metal joint formed by mechanically interlocking five layers of metal together three from the can end and two from the can body.
Hermetically sealed metal containers

Canning of fish

Canning is a method of storing food in airtight containers in a way that destroys potentially harmful microorganisms such as bacteria.

Most canned fish products are composed of ingredients that result in finished product with pH above 4.6 and water activity greater than 0.85.

These characteristics result in canned fish products being considered ‘low-acid canned food’. Canned fish have a shelf life of one year while frozen, oily fish should be used within two months.

Processing of Fish Canning 

Canned fish is conventionally covered with a liquid such as brine, vegetables oil tomato sauce or other sauces.

The canning process depends on the size of the fish. Small fish species such as sardines and pilchards are generally canned whole, with only the heads and tails removed. These whole-fish products are cooked in the can after it has been filled with brine or oil.

Canned fish is that it’s already cooked and ready for many easy dishes such as fish cakes, quiche, loaf, salads, sandwiches and appetizers.
Canning of fish

Heating in food processing

Heat Processing
The development of the modern eating process started in France during the first decade of the 1800s by Nicholas Appert who preserved foods in sealed glass jars in boiling water

In 1819, William Underwood of the United States started the first canning factory in Baltimore.

But to preserve foods in boiling water took too long, requiring about 6 hours, so salt was added to the water bath which increased the boiling temperature, thereby shortening the processing time.

However salt corroded the cans so the next innovation was to heat in steam under pressure. The higher the pressure, the higher the temperature and the shorter the processing time.

These early pressure chambers evolved into the modern retort.
Heat Processing

Canning of Food-The demand of can

Canning of Food-The demand of can
In 1861, the American Civil War began. Marching armies and wounded soldiers had to be fed. Canned foods provided healthy meals for thousands.

Weary soldiers drew strength from canned pork and beams oysters stew, fruit and milk.

Soldiers and sailors were grateful for Appert’s invention But other people were too. Canned food saved a lot of time and trouble.

Before canning was invented, people had to preserve their own food. Families killed pigs and cows and salted the meat.

They also dried and smoked meat over a fire. Preserved meat hung down from barn rafter. Some people rubbed the meat with pepper to keep away nibbling bars.

Milk, which soured quickly, was churned into butter or made into cheese.

Canning not only saved work and time, but it also provided a more interesting diet. Winter no longer meant just dried meat and fruit. People could choose from juicy peaches and savory stews.

Canned foods could travel across oceans and continents. In the midst of grassy prairies, far from oceans, families could feast on seafood.

In cold region, people could enjoy sweet pineapple form balmy lands.

For modern customers, bottled and canned foods are a regular part of life. But they are important in emergencies too. After hurricane or floods canned food quickly feed many people.

Relief workers also send cans of healthful foods to people in poor nations.

Appert’s preservation method was great gift to the world. The French honored Appert as a “Benefactor of Humanity” and presented him with a gold medal.

Appert had discovered that food sealed and heated in airtight containers did not spoil.
Canning of Food-The demand of can