Low Lactose ERP - Review Book

6. Based on the supporting information, what are the cons/weaknesses of the method?

The potential weakness of the method include: 1) It needs a prior knowledge of the unknown sample matrix, such as the glucose level in the sample, and whether ascorbic acid exist in sample or not, to determine how the sample is treated, and how the device is calibrated. 2) For low lactose concentration range (5-100 mg/100g), the recovery result seems not within the SMPR limit of 85-115%. 3) It is a proprietary method, do we know if any alternative source of the device and the chemical solutions are available or not? This method uses a simple device to measure the lactose level. It is very sensitive, can reach to the required LOQ. Also, there is no chromatography needed, so less sample prep procedure, and it is easy to use. Anyone who can use a pH meter should be able to operate this device. However, there are lots of chemicals or interferants that can contribute to the device signal. Some chemicals have very low response factors, but some have very high response factors, such as ascorbic acid, and vitamin Bs. The method tries to remove the background signal by a special sample treatment for ascorbic acid, and by changing how the calibration standard and Measurement Standard are prepared. This approach might be OK for samples with relatively high lactose range, but not adequate for low lactose range. Because it is not possible to accurately estimate how much signal is from the unknown sample matrix, and how much is from the lactose. I think this method is a very sensitive, reliable, and easy to use method to determine lactose concentration in milk and milk products for medium to high lactose concentration range. I am not confident that this method can accurately determine the lactose concentration in lactose-free products. This method also needs to know the glucose level in samples, and whether the ascorbic acid is in presence or not, which limited its use. The third concern is that it is a proprietary method, we need to find out if any alternative device is available, and if there is alternative way to prepare the solutions? I can not recommend this as a First Action method.

7. Any general comments about the method?

V. Final Recommendation Do you recommend this method be adopted as a First Action and published in the Official Methods of Analysis of AOAC INTERNATIONAL? Please specify rationale.