In addition, you can refer to this list . Note that the list includes caviar importers and exporters and thus they may not handle salmon roe. Caviar contains 47 vitamins and minerals. The best way is to use rubber sealed can. Pasteurised package is OK but not as good.
More information is here .
To export to US, see the guide from the US Food and Drug Administration , which includes proper labeling , general import procedures , and general advice . To export to Japan, you may contact the Japanese Consultant General in Hong Kong. You may also check the information provided by BizLinx .