Low Lactose ERP - Review Book

AOAC SMPR ERPs - 2019 METHOD REVIEW FORM

Submission Date

2019-09-06 12:20:19

Name

David Ellingson

E-mail

davidellingson@eurofinsus.com

Organization

Eurofins Food Integrity and Innovation

Title of Method

K-LOLAC Enzymatic Low Lactose Assay

AOAC Candidate Method Number (e.g. ALN-01)

LAC-006

Applicable SMPR

2018.009

I. Summary of the Method

A sequential enzymatic/spectrophotometric assay procedure is followed for measurement of lactose via free D-glucose. Deproteination/clarification and removal of free D-glucose is completed first with the extract. Any remaining free D-glucose is then measured using a hexokinase (HK)/Glucose 6-phosphate dehydrogenase (G-6PDH)/6-phosphogluconate dehydrogenase (6-PGDH) based assay procedure. This is followed by addition of beta-galactosidase with specificity to lactose into the same cuvette and the increase in D-glucose is measured. The difference in absorbance from the 2 measurements are used to calculate the amount of lactose.

II. Review of the Method Only 1. Does the applicability of the method support the applicability of the SMPR? If not, please explain what is missing. 2. Does the analytical technique(s) used in the method meet the SMPR? If not, please specify how it differs from what is stated in the SMPR. 3. Are the definitions specified in the SMPR used and applied appropriately in the method? If no, please indicate how the terms are used.

Yes, the applicability is met.

Yes, the requirements under analytical technique are met.

All definitions are met, except the units for reconstituted infant formula and liquids are expressed on a volume basis. The current SMPR reports on a mass basis. However, the slight difference in concentration seen between mass versus volume does not hinder the evaluation against the requirements set forth in the SMPR. A likely typo for CAS registry for lactose in Section 5.1 under target analytes. However, the correct CAS registry is used under Definitions.