Tacye asks: Common sense tells us that we should avoid uncooked animal products. But the Japanese enjoy longevity even though they eat a lot of raw fish. Is raw fish actually good for our health?
Wynnie says: As with most animal-based foods, there are health risks associated with eating raw fish. But these can be minimised if proper hygiene and strict regulations are adhered to.
Food poisoning from sushi and sashimi is fairly common, and accounted for 3 per cent of all food poisoning cases reported to Hong Kong's Department of Health in 2000.
Fresh and frozen raw seafood can contain bacteria such as salmonella and listeria, and tapeworm, roundworm or flatworm parasites. It's impossible to see, smell or taste any of this contamination.
The risk of roundworm infection is higher from freshwater fish, such as mackerel and salmon. Parasitical infection is more commonly caused by fish tapeworm: these can grow to just under a couple of metres long and may cause stomach cramps, diarrhoea, nausea, and tiredness.
However, most people don't have any symptoms of parasites, so they may only realise they are infected when they pass bits of the worm during a bowel movement.
To prevent food poisoning from raw seafood and to kill parasite larvae, raw fish must be frozen to at least minus 20 degrees Celsius for 24 hours.