Characterization and food application of an amperometric needle-type L-lactate sensor

There have been increasing needs for biosensing in the food industry because it is accurate, rapid and efficient. A needle-type L-lactate sensor with a three-layer membrane system which uses lactate oxidase as the biological component was prepared. The sensor had an optimum pH around 9-10 and an optimum temperature at 45 degrees C. The current response was stable over 40 days and specifically responded to L-lactic acid. The sensor gave accurate L-lactate measurements in kimchi and yogurt of 187.4 +/- 4.1 and 734.1 +/- 34.5 mg/dL, similar to those of a spectrophotometric L-lactate kit.