History of sushi
The traditional form of sushi is fermented fish and rice, preserved with salt in a process that has been traced to Southeast Asia, where it remains popular today. The term sushi comes from an archaic grammatical form no longer used .

In other contexts; literally, "sushi" means "it's sour",a reflection of its historic fermented roots.

The science behind the fermentation of fish packed in rice is that the vinegar produced from fermenting rice breaks the fish down into amino acids. This results in one of the five basic tastes, called umami in Japanese. The oldest form of sushi in Japan, Narezushi still very closely resembles this process. In Japan, Narezushi evolved into Oshizushi and ultimately Edomae nigirizushi, which is what the world today knows as "sushi."

Contemporary Japanese sushi has little resemblance to the traditional lacto-fermented rice dish. Originally, when the fermented fish was taken out of the rice, only the fish was consumed and the fermented rice was discarded. The strong-tasting and -smelling funazushi, a kind of narezushi made near Lake Biwa in Japan, resembles the traditional fermented dish. Beginning in the Muromachi Period (AD 1336–1573) of Japan, vinegar was added to the mixture for better taste and preservation. The vinegar accentuated the rice's sourness, and was known to increase its life span, allowing the fermentation process to be shortened and eventually abandoned. In the following centuries, sushi in Osaka evolved into oshi-zushi. The seafood and rice were pressed using wooden (usually bamboo) molds. By the mid 18th century, this form of sushi had reached Edo (contemporary Tokyo).

The contemporary version, internationally known as "sushi," was invented by Hanaya Yo at the end of Edo period in Edo. The sushi invented by Hanaya was an early form of fast food that was not fermented (therefore prepared quickly) and could be eaten with one's hands roadside or in a theatre. Originally, this sushi was known as Edomae zushi, because it used freshly caught fish in the Edo-mae (Edo Bay or Tokyo Bay). Though the fish used in modern sushi no longer usually comes from Tokyo Bay, it is still formally known as Edomae nigirizushi.

Sushi's Nutrition

The main ingredients of traditional Japanese sushi, raw fish and rice, are naturally low in fat, high in protein, carbohydrates, vitamins, and minerals. The same may not be said categorically of Western-style sushi, which increasingly features non-traditional ingredients such as mayonnaise, avocado, and cream cheese.

Most seafood is naturally low in fat, with fats found in seafood predominately being unsaturated and thus containing relatively high levels of Omega-3. Since sushi is often served raw, no cooking fat is introduced during its preparation. Some non-traditional ingredients such as cream cheese and mayonnaise that are sometimes found in Western-style sushi dishes can add significant amounts of unhealthy fat to a traditionally lean dish.

Fish, tofu, seafood, egg, and many other sushi fillings contain high levels of protein. Imitation meat such as crab stick may be lower in protein and other nutrition than their natural, unprocessed counterparts.

Vitamins and minerals are found in much of the seafood and vegetables used for sushi. The nutritional content is dependent on the ingredients used. For example, shrimp are high in calcium and iodine, while salmon are rich in Vitamin D. The gari and nori used to make sushi are both rich in nutrients. Other vegetables wrapped within the sushi also offer various vitamins and minerals.

Carbohydrates are found in the rice and the vegetables. Certain non-traditional ingredients can raise the carbohydrate level quite high, as with the fat level.

Health risks

Differential symptoms of parasite infections by raw fish.

As with most foods, sushi is not free from health risks, but these risks are minimized with proper preparation and service. Some large fish, such as tuna can harbor high levels of mercury. This is due to the tuna's position at the top of the food chain (among sea creatures). Thus, tuna can lead to when consumed in quantity.

Parasite infection by raw fish is rare in the modern world and involves mainly three kinds of parasites: Clonorchis Sinensis (a trematode/fluke), Anisakis (a nematode/roundworm) and Diphyllobothrium (a cestode/tapeworm).Infection risk of anisakis is particularly higher in fish which may live in a river such as salmon (shake) in Salmonidae, and mackerel. Such parasite infections can generally be avoided by boiling, burning, preserving in salt or vinegar, or freezing overnight.

Some forms of sushi, notably glogfish or puffer fugu and some kinds of shellfish, can cause severe poisoning if not prepared properly. Particularly, fugu has a lethal dose of tetrodotoxin in its internal organs and must be prepared by a licensed fugu chef who has passed the prefectural examination in Japan.

Sushi's Ingredients

Sushi rice

Sushi is made with white, short-grained,Japanese rice mixed with a dressing made of rie vinegar,sugar,salt, and occasionally kombu and sake. It has to be cooled to room temperature before being used for a filling in a sushi or else it will get too sticky while being seasoned. Traditionally, the mixing is done with a hangiri, which is a round, flat-bottom wooden tub or barrel, and a wooden paddle

Sushi rice is prepared with short-grain Japanese rice, which has a consistency that differs from long-grain strains. The essential quality is its stickiness or glutinousness. Rice that is too sticky has a mushy texture; if not sticky enough, it feels dry. Freshly harvested rice (shinmai) typically contains too much water, and requires extra time to drain the rice cooker after washing.

Nori

The black seaweed wrappers used in makimono are called nori. Nori is a type of algae, traditionally cultivated in the harbors of Japan. Originally, algae was scraped from dock pilings, rolled out into thin, edible sheets, and dried in the sun, in a process similar to making rice paper. Whereas in Japan, nori may never be toasted before being used in food, many brands found in the U.S. reach drying temperatures above 42 °C.

The standard size of a whole nori sheet mentioned above influences the size of maki-mono. A full size sheet produces futomaki, and a half produces hosomaki and temaki. To produce gunkan and some other makimono, an appropriately sized piece of nori is cut from a whole sheet.

Nori by itself is an edible snack and is available with salt or flavored with teriyaki sauce. The flavored variety, however, tends to be of lesser quality and is not suitable for sushi.

Toppings and Fillings

Seafoods such as squid, eel, pike conger, octopus, shrimp (ebi and amaebi), clam(mirugai, aoyagi and akagi), fish roe, sea urchin, crab and various kinds of shellfish (abalone, prawn, scallop) are the most popular seafoods in sushi. Oysters, however, are less common, as the taste is not thought to go well with the rice. Kani kama, or imitation crab stick, is commonly substituted for real crab, most notably in California rolls.

Pickled daikon radish in shinko maki, pickled vegetables, fermented soybeans in nattō maki, avocado, cucumber, asparagus, yam, pickled ume, gourd, burdock, and sweet corn may be mixed with mayonnaise.

Tofu and eggs (in the form of slightly sweet, layere omelette and raw quail eggs ride as a gunkan-maki topping) are common.

Condiments

Sushi is commonly eaten with condiments. Sushi may be dipped in shoyu, soy sauce, and may be flavored with wasabi, a piquant paste made from the grated root of the Wasabi Japanica plant.

True wasabi has anti-microbial properties and may reduce the risk of food poisoning.The traditional grating tool for wasabi is a sharkskin grater. An imitation wasabi (seiyo-wasabi), made from horseradish and mustard powder and dyed green is common. It is found at lower-end kaiten zushi restaurants, in benti-box sushi and at most restaurants outside of Japan.

Gari, sweet, pickled ginger is eaten with sushi to both cleanse the palate and aid in digestion. In Japan, green tea is invariably served together with sushi. Better sushi restaurants often use a distinctive premium tea known as mecha. In sushi vocabulary, green tea is known as agari.

Types of Sushi

Types of Sushi

Nigiri-zushi

Nigirizushi

Nigirizushi consists of an oblong mound of sushi rice that is pressed between the palms of the hands, usually with a bit of wasabi, and a topping draped over it. Toppings are typically fish such as salmon, tuna or other seafood. Certain toppings are typically bound to the rice with a thin strip of nori, most commonly octopus (tako), freshwater eel (unagi), sea eel , squid (ika), and sweet egg (tamago). When ordered separately, nigiri is generally served in pairs. A sushi set may contain only one piece of each topping.

Gunkanmaki is a special type of nigirizushi: an oval, hand-formed clump of sushi rice that has a strip of "nori" wrapped around its perimeter to form a vessel that is filled with some soft, loose or fine-chopped ingredient that requires the confinement of nori such as roe, natto, oysters, sea urchin, corn with mayonnaise, and quail eggs.

Temarizushi is a ball-shaped sushi made by pressing rice and fish into a ball-shaped form by hand using a plastic wrap.

Makizushi

Makizushi is cylindrical piece, formed with the help of a bamboo mat. Makizushi is generally wrapped in nori, but can occasionally be found wrapped in a thin omelette, soy paper, cucumber, or parsley. Makizushi is usually cut into six or eight pieces, which constitutes a single roll order. Below are some common types of makizushi, but many other kinds exist.

Futomaki is a large cylindrical piece, with nori on the outside. A typical futomaki is three or four centimeters in diameter. They are often made with two or three fillings that are chosen for their complementary tastes and colors. Futomaki is often vegetarian, but may include non-vegetarian toppings such as tiny fish roe and chopped tuna.

Hosomaki is a small cylindrical piece, with the nori on the outside. A typical hosomaki has a diameter of about two centimeters. They generally contain only one filling, often tuna, cucumber, kanpyo, thinly sliced carrots, or, more recently, avocado. Kappamaki, a kind of Hosomaki filled with cucumber. Traditionally, Kappamaki is consumed to clear the palate between eating raw fish and other kinds of food, so that the flavors of the fish are distinct from the tastes of other foods. Tekkamaki is a kind of Hosomaki filled with raw tuna. Negitoromaki is a kind of Hosomaki filled with scallion and chopped tuna. Fatty tuna is often used in this style. Tsunamayomaki is a kind of hosomaki filled with canned tuna tossed with mayonnaise.

Temaki is a large cone-shaped piece of nori on the outside and the ingredients spilling out the wide end. A typical temaki is about ten centimeters long, and is eaten with fingers because it is too awkward to pick it up with chopsticks. For optimal taste and texture, Temaki must be eaten quickly after being made because the nori cone soon absorbs moisture from the filling and loses its crispness and becomes somewhat difficult to bite.

Uramaki is a medium-sized cylindrical piece, with two or more fillings. The filling is in the center surrounded by nori, then a layer of rice, and an outer coating of some other ingredients such as roe or toasted sesame seeds. It can be made with different fillings such as tuna, crab meat, avocado, mayonnaise, cucumber, carrots.

Oshizushi

Oshizushi is a pressed sushi from the Kansai Region. A block-shaped piece formed using a wooden mold, called an oshibako. The chef lines the bottom of the oshibako with the toppings, covers them with sushi rice, and then presses the lid of the mold down to create a compact, rectilinear block. The block is removed from the mold and then cut into bite-sized pieces.

Inarizushi

Inarizushi is a pouch of fried tofu filled with usually just sushi rice.The pouch is normally fashioned as deep-fried tofu. Regional variations include pouches made of a thin omelette, fukusa-zushi or chakin-zushi. A very large version, sweeter than normal and often containing bits of carrot, is popular in Hawaii, where it is called "cone sushi."

Sukeroku

Sukeroku is the combination set of inarizushi and makizushi, which is served as a single-portion takeout style sushi-pack. Sukeroku is a cheap sushi-pack and often vegetarian.

Chirashizushi

Chirashizushi is a bowl of sushi rice with other ingredients mixed in. It is commonly eaten in Japan because it is filling, fast and easy to make. The ingredients are often chef's choice. Edomae chirashizushi (Edo-style scattered sushi) is an uncooked ingredient that is arranged artfully on top of the sushi rice in a bowl. Gomokuzushi (Kansai-style sushi) are cooked or uncooked ingredients mixed in the body of rice in a bowl.

Narezushi

Narezushi is a traditional form of fermented sushi. Skinned and gutted fish are stuffed with salt, placed in a wooden barrel, doused with salt again, then weighed down with a heavy tsukemonoishi (pickling stone). As days pass, water seeps out and is removed. After six months this funazushi can be eaten, remaining edible for another six months or more.