In order to evaluate the accuracy of the CDR method to test lactose in milk, 6 samples of commercial lactose-free milk from different producers were selected. The samples was stabilised and in 4 of these, an aliquot of whole milk (5% lactose) was added and thus a known amount of lactose.
The accuracy of the CDR FoodLab® method is assessed by determining the correlation between the results of the 10 milk samples obtained by the analyses with CDR FoodLab® and those obtained by the Istituto Zooprofilattico using the HPLC method (High Performance Liquid Chromatography) as provided by the reference method MP 02/050 rev.6- 2018.
The table shows data obtained with two different CDR FoodLab® instruments, used by two different operators in order to also assess the reproducibility of the CDR method.
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| CDR FoodLab® 1 | CDR FoodLab® 2 | CDR FoodLab® average (%) | IZS Lab. (%) |
Sample 1 | Fresh | 0,04 | 0.03 | 0,03 | 0,030 |
Sample 2 | UHT | 0,01 | <0,01 | 0,01 | <0,025 |
Sample 3 | UHT | 0,03 | 0,02 | 0,02 | <0,025 |
Sample 4 | Fresh | 0,13 | 0,11 | 0,12 | 0,126 |
Sample 5 | Sample 2 + 0,35% | 0,35 | 0,36 | 0,35 | 0,450 |
Sample 6 | UHT | 0,18 | 0,19 | 0,19 | 0,179 |
Sample 7 | UHT | 0,02 | 0,03 | 0,02 | <0,025 |
Sample 8 | Sample 7 + 0,1% | 0,11 | 0,12 | 0,12 | 0,147 |
Sample 9 | Sample 6 + 0,1% | 0,26 | 0,27 | 0,27 | 0,315 |
Sample 10 | Sample 3 + 0,1% | 0,12 | 0,14 | 0,13 | 0,143 |
Conclusions
The two methods provided highly correlated results (R2= 0,990) confirming the excellent accuracy of the CDR method.
Download the Correlation study between the CDR FoodLab® method for lactose determination and the reference method MP 02/050 rev.6- 2018 carried out by a major Istituto Zooprofilattico Sperimentale.
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