It is not advisable to gut mackerel at 1 PM, handle it in a home freezer, and then eat it raw in the evening. Effective Anisakis parasite control through freezing requires specific time and temperature conditions that cannot be substituted by just a few hours.
If you plan to eat mackerel raw in the evening, use mackerel that has been safely managed for raw consumption or cook it thoroughly to the center. The fish should be cooled immediately after gutting, and if there is any uncertainty about the timing or temperature control, choosing not to eat it is safer.
Judging from 1 PM to Evening
You cannot judge the safety for raw consumption based on the time the fish was gutted alone. Check the processing upon arrival, whether the fish was labeled safe for raw eating, the storage temperature, and the time when guts were removed.
“It was refrigerated, so it’s safe” or “It was prepared with vinegar or salt, so it’s safe” are not guaranteed. Vinegar and salt are used to adjust flavor and do not replace parasite control measures.
Why Freezing Cannot Substitute
Japan’s Ministry of Health, Labour and Welfare recommends freezing at -20°C for at least 24 hours or thorough cooking to the center as effective control against Anisakis parasites. Household freezers have variable temperatures, and the thickness of the fish affects freezing conditions, so short-term freezing until evening is unlikely to achieve the same effect.
Also, freezing does not eliminate all bacteria. It is risky to convert mackerel whose raw consumption management is not verified into sushi toppings by freezing alone.
When Cooking Instead
Change to a dish that is fully cooked through to the center instead of raw consumption. After cooking, do not leave it at room temperature for long and only take out as much as you intend to eat.
Next Checks to Make
- Is the mackerel sold labeled for raw consumption?
- Has temperature been properly controlled from purchase to preparation?
- Can the freezing temperature and duration be documented?
- If there is any doubt, can you switch to cooking the fish?
