Raw frozen fish that was being prepared for use in sushi dishes was found defrosting at room temperature, leaving diners at risk of infection, an inspectors' report has revealed.
Freezers where fish was being stored for the Japanese delicacy were also not under -20C.
Some of the product was also being delivered without temperature checks.
The breaches that failed to safeguard human health were revealed in an audit of 11 sushi manufacturers, restaurants and takeaway outlets carried out by the Food Safety Authority of Ireland (FSAI).
Overall, 90pc of the inspected businesses fell short and did not have adequate safety controls in place.
Three major manufacturers in the audit supply and produce sushi for the corporate sector.
"Raw fish from both fresh water and salt water can be a potential source of human infection due to the presence of parasites," said the watchdog's chief executive, Pamela Byrne.
"Therefore, controls to ensure the raw fish used in sushi is parasite-free are critical, as there is no cooking process in sushi to kill off potentially harmful parasites.
"Sushi rice needs specific food safety controls to avoid the presence of specific food-borne bacteria commonly found in rice."
The audit revealed 76 breaches of food safety regulations.
Of the 11 premises audited, only one had no breaches of food safety and hygiene legis- lation.
The FSAI inspection was carried out in light of a reported 80pc increase in the number of restaurants offering sushi since last year as more people perceive the dish as healthy, low-calorie and vitamin-rich.
There was a 60pc rise in sushi orders since 2015 by one of the major delivery companies.
The eight restaurants audited ranged from food outlets where sushi was served on the premises to small outlets where sushi was delivered to people in their homes.
"The audit focused on the food safety controls in place regarding the freezing of fish for parasite control, time and temperature controls and pH controls for acidified sushi rice," Dr Byrne said.
Sushi rice is short-grain rice cooked with vinegar and other ingredients.
There were also basic hygiene breaches, with one worker seen washing their hands with their gloves on.
Inspectors found unclean equipment and a lack of training of staff in relation to the safety controls needed for sushi.
They also found unsuitable cloths being used to wrap fish.
"It showed that over three- quarters of the food businesses did not have adequate food safety controls in place for this," Dr Byrne said.
"We also found poor trace- ability records, which are critical in the event of a food recall, if required.
"The poor standards overall are worrying and suggest a lack of awareness by the sector as a whole of the serious food safety risks that sushi can pose if there are inadequate food safety controls in place."
All of the outlets inspected have now rectified their standards, and the FSAI is distributing specific advice to help the wider sector.
At the time of the audit, the main sources of advice were from New South Wales in Australia and the UK.
Omega-3 fatty acids found in fish are linked to heart protection and improved circulation.