pH Measurement To Determine Acidification of Sushi Rice 

LAQUAtwin is a series of pocket ION meters. Using Ion Selective Electrode (ISE) technology, they are available for measuring Conductivity, Calcium, Nitrate, Potassium, Sodium, Salt concentration and pH measurement. Using just a tiny amount of sample, the LAQUAtwin proprietary flat sensors can quickly and accurately measure the values of the chemical parameters in the field.

Introduction

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 pocket pH 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.

Method

Acetic acid (vinegar) should be mixed into the rice according to the following table. (click to enlarge)

A small sample of the rice mixture is placed on the flat sensor of the LAQUAtwin pocket pH 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 senor 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 pocket pH 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 pocket pH Meter an indispensable tool for food testing.

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

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

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