Canned fish

Cannedortinned fisharefood fishwhich have beenprocessed, sealed in an airtight container such as a sealedtin can, and subjected to heat.Canningis a method ofpreserving food, and provides a typicalshelf liferanging from one to five years. They are usually opened via acan opener, but sometimes have a pull-tab so that they can be opened by hand. In the past it was common for many cans to have a key that would be turned to peel the lid of the tin off; most predominatelysardines, among others.
Fish have lowaciditylevels at which microbes can flourish. From a public safety point of view, foods with low acidity (pHgreater than 4.6) needsterilizationat high temperatures of 116–130 °C (241–266 °F). Achieving temperatures above the boiling point requirespressurized cooking.After sterilization, the containing can prevents microorganisms from entering and proliferating inside. Other than sterilization, no method is dependable as a preservative. For example, the microorganismClostridium botulinum(which causesbotulism) can only be eliminated at temperatures above the boiling point.
Preservationtechniques are needed to preventspoilageand lengthenshelf life. They are designed to inhibit the activity of spoilagebacteriaand the metabolic changes leading to a loss of quality.Spoilage bacteriaare the specific bacteria that produce the unpleasant odours and flavours associated with spoiled fish.
The "father of canning" is the FrenchmanNicolas Appert. In 1795, he began experimenting with ways to preserve fish in jars. He placed jars of fish in boiling water.During the first years of theNapoleonic Wars, the French government offered a 12,000francprize to anyone who could devise a cheap and effective method of preserving large amounts of food. The larger armies of the period required increased and regular supplies of quality food. Appert submitted his invention and won the prize in January 1810. The reason for lack of spoilage was unknown at the time, since it would be another 50 years beforeLouis Pasteurdemonstrated the role of microbes in food spoilage. However, glass containers presented problems for transportation. Shortly after, the British inventor and merchantPeter Durandpatented his own method, this time in atin can, creating the modern-day process of canning foods.
Canning was used in the 1830s in Scotland to keep fish fresh until it could be marketed. By the 1840s, salmon was being canned in North America in Maine and New Brunswick.American commercial salmon canneries had their origins in California, and in the northwest of the US, particularly on the Columbia River. They were never significant on the U.S. Atlantic coast. By the 1940s, the principal canneries had shifted to Alaska.
Asalmon canneryis a factory thatcommercially canssalmon. It is afish processingindustry that pioneered the practice of canning fish in general. It became established on the Pacific coast of North America during the nineteenth century, and subsequently expanded to other parts of the world that had easy access to salmon.
Prior to canning, fish were salted to preserve them. Through preservation, fish could be transported and sold large distances from where they were caught. At the start of the 19th century, salted salmon caught in Alaska was available in St. Petersburg.Shortly after, theNorthwest Fur Companystarted marketing salted salmon from the Columbia River. It then merged with theHudson's Bay Company, and the salmon was marketed in Australia, China, Hawaii, Japan and the eastern United States. Later, some salmon salteries were converted to salmon canneries.
The first industrial scale salmon cannery in North America was established in 1864 on a barge in theSacramento Rivernear West Sacramento by the four Hume brothers together with their partner Andrew S. Hapgood.In 1866 the Hume brothers relocated the business to a site 50 miles inland on theColumbia River.The history of North American salmon canneries is exemplified by their history on the Columbia River. Within a few years each of the Hume brothers had his own cannery. By 1872,Robert Humewas operating a number of canneries, bringing in Chinese workers willing to work for low wages to do the cannery work, and having local Native Americans do the fishing. By 1883, salmon canneries had become the major industry on the Columbia River, with 1,700gillnetboats supplying 39 canneries with 15,000tonnesof salmon annually, mainlyChinook.
Sardines(or pilchards) are canned in many different ways. At the cannery, the fish are washed, their heads are removed, and the fish are cooked, either by deep-frying or by steam-cooking, after which they are dried. They are then packed in eitherolive,sunflowerorsoybeanoil, water, or in atomato,chili, ormustardsauce.
Canned sardines in supermarkets may actually besprat(such as the“brisling sardine”) orround herrings. Fish sizes vary by species. Good quality sardines should have theheadandgillsremoved before packing.They may also beevisceratedbefore packing (typically the larger varieties). If not, they should be purged of undigested or partially digested food orfecesby holding the live fish in a tank long enough for them to empty their digestive systems.
Sardines are typically tightly packed in a small can which is scored for easy opening, either with a pull tab (similar to how abeverage canis opened), or akey, attached to the underside of the can. Thus, it has the virtues of being an easily portable, nonperishable, self-contained food.
The close packing of sardines in the can has led to their metaphorical use of the name ("packed like sardines") in describing any situation where people or objects are crowded together, for instance, in abusorsubway car. "Sardines" has also been used asthe name of a children's game, where one person hides and each successive person who finds the hidden one packs into the same space until there is only one left out, who becomes the next one to hide.
Tunais canned in ediblevegetable oils, inbrine, in water, or in various sauces. In the United States, canned tuna is sometimes calledtuna fishand onlyalbacorecan legally be sold in canned form as "white meat tuna";in other countries,yellowfinis also acceptable. While in the early 1980s, canned tuna in Australia was most likelysouthern bluefin; as of 2003it was usually yellowfin,skipjack, ortongol(labelled "northern bluefin").
Tunas are often caught far from where they are processed for canning, so poor interim conservation can lead to spoilage. Tuna is typicallyguttedby hand and later precooked for prescribed times of 45 minutes to three hours. The fish are then cleaned andfilleted, canned (and sealed), with the dark lateral blood meat often separately canned forpet food(catordog).  The sealed can itself is then heated (called "retort cooking") for 2–4 hours.
The retort cooking process kills any bacteria but retains thehistaminethat can producerancidflavors. The international standard sets the maximum histamine level at 200 milligrams per kilogram. An Australian study of 53 varieties of unflavored canned tuna found none to exceed the safe histamine level, although some had "off" flavors.The level ofomega-3 oilsfound in canned tuna can be highly variable, since some common manufacturing methods destroy omega-3 oils.
Australian standards once required cans of tuna to contain at least 51% tuna meat, but these regulations were dropped in 2003.The remaining weight is usually oil or water. In the United States, theFood and Drug Administration(FDA) regulates the amount of tuna in a can.In 2008, some tuna cans dropped from 6 ounces (170 g) to 5 ounces (140 g) due to "higher tuna costs".In the United States, 52% of canned tuna is used forsandwiches, 22% forsalads, and 15% forcasserolesanddried, packaged meal mixes.
Other fish commonly canned includeanchovy,cod,herring, andmackerel.