Canned fish: Safe and tasty too!

Super-convenient canned seafood: better than fresh?

Canned fish are fish which have been processed, sealed in an airtight container such as a sealed tin can, and subjected to heat. Canning is a method of preserving food, and provides a typical shelf life ranging from one to five years.

Fish have a low acidity at levels where microbes can flourish. From a public safety point of view, foods with low acidity (a pH more than 4.6) need sterilization under high temperature (116-130 °C). To achieve temperatures above the boiling point requires a method ofpressurized cooking which is provided by the containment within the can.^[1] After sterilization, the containing can prevents microorganisms from entering and proliferating inside. Other than sterilization, no method is perfectly dependable as a preservative. For example, the microorganism Clostridium botulinum (which causes botulism), can only be eliminated at temperatures above the boiling point.

Such preservation techniques are needed to prevent fish spoilage and lengthen shelf life. They are designed to inhibit the activity of spoilage bacteria and the metabolic changes that result in the loss of fish quality. Spoilage bacteria are the specific bacteria that produce the unpleasant odours and flavours associated with spoiled fish.

(Wikipedia)

Mercury alert: Is canned tuna safe to eat?

The tuna sandwich is a lunchbox staple. But several species of tuna, like other large ocean fish, contain higher-than-average amounts of mercury.This is of particular concern for young children, whose nervous system, brain, heart, kidneys and lungs are all susceptible to the harmful effects of mercury.

But parents and kids need not give up tuna altogether. There are two main kinds of canned tuna: chunk light and solid or chunk white (albacore). Most canned white tuna is albacore. Its mercury levels are almost three times higher than the smaller skipjack, used in most canned light tuna.

These recommendations are based on EPA guidance and estimates of mercury in the most popular canned tunas:

·         Canned white, or albacore (0.32 parts per million of mercury). Children under six can eat up to one 3-ounce portion a month; children from 6–12, two 4.5-ounce portions a month. Adults, including pregnant women, can safely eat it up to three times a month (women, 6-ounce portions; men, 8-ounce portions).

·         Canned light — the safer choice (0.12 parts per million of mercury). Children under six can eat up to three 3-ounce portions per month. Older children and adults can safely eat it once a week. But look out for “gourmet” or “tonno” labels. They are made with bigger yellowfin tuna and can contain mercury levels comparable to canned white.

·         A better alternative is canned salmon (mostly sockeye or pink from Alaska), which is low in contaminants and high in heart-healthy omega-3s. It's also sustainably caught in Alaska and similarly priced, making it a great choice all around.

Keep an eye on school lunches. If your child eats tuna in school lunches, it's best to find out what types are being offered and how often.
A study by the Mercury Policy Project in the US found a wide range of mercury levels in both light and white tuna from government sponsored school lunch programs. Some of the canned albacore/white tuna tested had mercury levels almost four times the average level reported by US-FDA.