Our health inspector told me to buy a pH meter for sushi. What do I get, and where?
– Casey, Co-Manager, China House, Janesville, Wis.
Sushi is best made with rice slightly warmer than room temperature. Over a service period, that means that the rice—a potentially hazardous food—is kept in the danger zone. Because the rice is acidified with vinegar, holding it warm for a limited time can be safe, and with proper record keeping is allowed in most municipalities. You may need a formal HACCP plan or simply time and temperature logs. In either case, it is important to record the time and temperature at which the rice is held and to verify that the pH (acidity) is below 4.6, per the FDA Food Code.
When writing about this issue five years ago, I advised that any reliable measure of pH, provided the food is measured correctly, would work—from simple test strips to expensive meters. However, as more municipalities develop specific regulations for sushi, and as sushi becomes a more common offering, I am seeing the bar being raised with inspectors expecting accurate digital records maintained for a long period of time.
Fortunately, technology has kept up since I last wrote on this topic, and a number of fairly reliable low-cost digital meters exist. In addition, there are meters that connect to apps for long-term record keeping (important if, for example, a guest complains of a past illness). Many meters will measure temperatures at the same time, streamlining the recording process during a busy service. Since pH meters are used in a variety of commercial applications, be sure to buy one that is food-safe or even specifically designed for sushi.
Dave-Roger Grosvenor, president of Philadelphia-based food safety firm VII Principles, advises, “There are some inexpensive pH meters on sale. No need for an expensive one. The pH meter should be able to submerge in slurry … created from the rice water solution. The meter is required to ensure the acidity of the rice attains a minimum [pH of] 4.6 … Important also, the restaurant must be able to calibrate the meter by us[ing] buffers (pH 4.01 for acid; pH 7.01 for base or neutral; pH 10.01 for alkaline). … Most cities require an approved HACCP plan.”
As always, check with your local restaurant association and health department regarding specific requirements in your municipality. More on sushi food safety here.