At Sydney Fish Market, we often get asked what the definition of 'sashimi-grade' is. Frustratingly, there's no easy answer to that question... Here's a quick run-down.
The Actual Definition
'Sashimi-grade' refers to seafood that is suitable and safe to eat raw. But who determines this? And what makes some seafood products sashimi-grade and some not?
Everything is Sashimi-Grade!
Every seafood product has been sashimi-grade at one point in time. Say you catch a fish yourself, out on the tinny. If you filleted it on the boat under sanitary conditions and took a bite there and then, that would be considered sashimi-grade (as long as it's an edible species). That’s because you know for sure how fresh that fish is, how it's been handled, and exactly where it's been.
But What Gets Labelled Sashimi-Grade?
If you're not catching your own fish, what is labelled sashimi-grade and what isn't comes down to a little thing called the cold chain. This refers to the seafood industry's ability to keep seafood products within an optimal temperature range for as long as possible before you purchase it.
Essentially, what fishmongers label as 'sashimi-grade' is at their discretion. Fishmongers have strong relationships with their suppliers to ensure that they can trust their handling methods. If they know that a particular species has been caught and handled optimally throughout the supply chain, and always kept at a safe temperature, they will label it sashimi-grade. Needless to say, all fishmongers are governed by food safety legislation, so it's in their interest to label things correctly!
What Are These Handling Methods? 
Handling methods vary between species, so let's use one of the most popular sashimi-grade fish, Tuna, as an example.
Sashimi-grade Tuna are line-caught, landed onto a mattress (to minimise bruising) and killed instantly by brain-spiking (a process called ike jime). This prevents the fish from struggling and releasing stress hormones, and helps to keep the body temperature low. The fish is then bled immediately, removing heat and waste products, and put into an ice slurry to drop its temperature as close to 0ºC as quickly as possible.
This fish is then kept as cold as possible for the entirety of its journey to Sydney Fish Market, where it can be safely labelled as sashimi-grade!
What About Snap-Freezing?
It is a common misconception that seafood has to have been 'snap-frozen' to 'kill parasites' and classify it as sashimi-grade. This is not true for Australian seafood: it's simply about freshness and handling. Parasites are rarely a worry in Australia, where the industry has strong food safety controls in place and where we have such fantastic, consistent access to fresh-caught seafood.