Rice used for sushi must have a pH of less than 4.6. At pH levels below 4.6, most pathogenic bacteria do not grow or produce toxins1. Thus, the rice must be acidified using acetic acid (vinegar) to be classified as non-hazardous. The LAQUAtwin pH pocket meter is used as quality control check to ensure that the rice is adequately acidified, before selling to consumers. This is an easy, quick check method used to abide to the ANZ Standards2 in ensuring that customers are safely consuming sushi.


Acetic acid (vinegar) should be mixed into the rice according to the following table: 

A small sample of the rice mixture is placed on the flat sensor of the LAQUAtwin pH pocket meter and measured. If the measured value is above pH 4.6, add more acetic acid to the rice mixture and stir well. Place new rice sample on the sensor and repeat testing process. After tests, wash the sensor with diluted soap water and pat dry with a paper tissue.

Results and Benefits

The use of accurate pH testing in controlling the quality of sushi rice prevents the growth of pathogenic bacteria and toxins. The LAQUAtwin pH pocket meter is small and compact; convenient to carry around in your pocket and is ideal for on-site testing. Its easy-to-use interface makes the LAQUAtwin pH pocket meter an indispensable tool for food testing.

References and Suggested Readings

1 Hocking, A.D; 2003. Foodborne Microorganisms of Public Health Significance, AIFST, Waterloo

Food Safety Guideline for Preparation and Display of Sushi, June 2007, NSW/FA/F1005/0706

LAQUAtwin: the only meters with flat sensor technology.

HORIBA’s highly-sensitive, flat sensor technology opens up new possibilities for sampling and sample types. Only a small amount of sample is required, so you can easily sample in situ without the need for beakers or other labware. Sensors are easily replaced as required.

Calibrate and measure at the touch of a button — the smiley face will tell you when the result can be read.

Hassle-free automatic calibration with a few drops of standard solution reassures you of your measurement accuracy. Two-point calibration is also possible.*
*Except for B-711

LAQUAtwin is fully waterproof and dustproof.

The meter and sensor are fully waterproof* and dustproof, so you can take it anywhere.
* IP67 rated. Will withstand immersion for 30 minutes at 1 m. Not suitable for underwater use.

Carry case comes as standard for handy portability.

The compact carry case contains everything you need for your measurements, including the standard solution and sampling sheets.

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