Dry, uncooked rice is not considered a potentially hazardous product. Store uncooked rice at room temperature in a dry, covered container placed at least 6 inches off the ground.
The cooking process adds water, making cooked rice a potentially hazardous food that can support the growth of bacteria, which requires additional controls to keep the product safe.
To ensure you are preparing the safest sushi rice possible:
Store sushi rice either below 41°F±2° or above 135°F±2° (3-501.16)
Use time as a public health control (3-501.19) – If the rice is stored between 41°F±2° and 135°F±2° (the temperature danger zone) it must be served within four hours of preparation.
Your facility must have a written procedure maintained onsite, and train staff to follow the procedure. Once prepared, you must time label the container of sushi rice and ensure any rice remaining after four hours is disposed.
You may have a sample of your sushi rice (made from a consistent recipe) tested by a certified laboratory to determine if the amount of vinegar you add makes the rice so acidic that it will not support the growth of bacteria, essentially making it non-potentially hazardous (see below for details).