Eating sushi with a mollusc allergy

My mother and I will be travelling to Japan for the first time next April. We're big fans of sushi, so we're really looking forward to eat tons while travelling through Japan!

However, my mother has a severe allergy to mollusc, more specifically to : (1) scallop, (2) mussel, (3) oyster and (4) clam.

Fish, shrimp, crab, lobster, etc. are totally fine. My concern is that it seems that sushi restaurants in Japan often serve molluscs and they don't necessarily pay lots of attention to cross-contamination...

Is it unrealistic to think that my mother will be able to indulge sushis without the constant risk and fear of being sick while travelling through Japan?

And does anyone have some recommendations of (great) sushi restaurants that don't serve any mollusc and/or where we can be sure there won't be any risk of cross-contamination?

Most of our trip will be spend in Tokyo and Osaka.

Thank you so much for your help!

Practically speaking, then the main ingredients you need to watch out for in a sushi restaurant would be scallop and clam (oyster and mussels arenft normally used in sushi). Scallops are used as part of sushi, and some places use clam for their soup. (Any problem with octopus or squid?)

Apart from the main ingredients themselves, yes, cross-contamination would of course be a concern. I know they wipe the knife in-between cutting (to keep the knife sharp and for flavor concern), but I donft know how careful they are in terms of allergy care.

Youfd need to look for gallergy accommodatingh place, either through word-of-mouth or recommendation (hotel concierge, or research in advance). I have heard of people who cannot take soy sauce but want to try sushi so they ask about gluten-free soy sauce (or bringing their own), and some restaurants do provide such ingredients. I just did some search (in Japanese) and some places say upfront gplease let us know if you have any allergy.h

I got oysters at a sushi store I frequent in Kyoto (last visit was October), but that came as part of a course meal where the chef decides what is best on the day when making the menu. However, for any allergies he changes the menu to accommodate those, or simply preferences - I'm personally not a fan of shellfish, but I eat it occasionally. (I know that his shop is also gluten free.)
When I read the question yesterday, the item that is the biggest concern would be the cross-contamination. Cleaning between preparing items like wiping knives or hands probably would be insufficient and I have had guests rule out large sections of menus because of common cooking areas (grill or fryers for example). You would want to be visiting a store that either did not do shellfish, or was particularly sensitive to (and understood) your allergy.

OP's post is uncertain.
there are at least two meanings for "severe". one is severe symptom, if the reaction occurs, or another is that the reaction occurs with very low amount of allergens. also, OP does not mention what is threshold level of the reaction , for example, gram level, mg level, or ng level of allergic foods (or ingredients).
because allergic reactions can be avoided with ordinary precautions by each patient and parents of child patients, I don't think it is necessary to consider cross-contaminations in higher level.
in Japan, the word, cross-contamination, is a technical word only used in natural scientific fields. most people don't know the word itself.

Hi MarieLaurenceN,

I understand what you mean. While it is easy to avoid certain allergens at any sushi bar, it can be very tricky when your allergy is so severe that you need to make sure your allergens weren't used in the kitchen or the factories beyond.

By Googling, I can see that many sushi companies provide lists of allergens that have the risk of contamination in their process lines, but I couldn't really find anything that can assure you about avoiding specific allergens just for certain customers. And from what I've found so far, some of your allergens would always have risk of contamination at a sushi place.

What I can suggest is to find a good concierge. Perhaps you can talk to a concierge at your local branch of a big hotel chain. Then hopefully the concierge, without language barrier, can guide you to the right places if any. I did that a long time ago for a family member with not-so-severe allergy. I know it's nothing ideal, but I thought it could be better than having no suggestions at all.

Another idea is to find a fisherman, amateur or professional, and eat something fresh from the sea. It's quite a common thing to do in Japan, as long as you know someone who likes to fish.

I hope your mother has a great time in Japan, regardless.