Repeatability and Accuracy of Dye-Binding and Infra-Red Methods for Analyzing Protein and Other Milk Components ¹

Area of Science:

• Dairy Science
• Analytical Chemistry
• Food Analysis

Background:

• Accurate analysis of raw milk composition is crucial for the dairy industry.
• Traditional methods for determining protein, fat, lactose, and solids-not-fat can be time-consuming.
• Infrared (IR) spectroscopy offers a rapid alternative for milk analysis.

Purpose of the Study:

• To evaluate the accuracy and repeatability of the Milko-Scan 104 IR device for analyzing raw milk.
• To compare the Milko-Scan 104 with established dye-binding methods (Udy, Pro-Milk Mark II) for protein analysis.
• To assess the Milko-Scan 104's accuracy for milkfat, lactose, and solids-not-fat against reference methods.

Main Methods:

• Comparative analysis of protein content using Udy Analyzer, Pro-Milk Mark II, and Milko-Scan 104.
• Evaluation of Milko-Scan 104 for milkfat, lactose, and solids-not-fat against Mojonnier and Milko-Tester methods.
• Statistical analysis of repeatability and standard deviation of accuracy (σ_y,x) for each method.

Main Results:

• All three methods demonstrated high repeatability for protein analysis (<0.05%).
• Standard deviations of accuracy for protein analysis were comparable across Udy Analyzer (0.063), Pro-Milk (0.062), and Milko-Scan (0.067).
• Milko-Scan 104 showed good accuracy for milkfat (σ_y,x = 0.054 vs. Mojonnier, 0.050 vs. Milko-Tester), lactose (σ_y,x = 0.083 vs. LC), and solids-not-fat (σ_y,x = 0.073 vs. Mojonnier).

Conclusions:

• The Milko-Scan 104 IR device is a reliable and accurate tool for routine analysis of protein in raw milk.
• The Milko-Scan 104 also provides accurate determinations of milkfat, lactose, and solids-not-fat, comparable to reference methods.
• This study validates the use of infrared spectroscopy as an efficient method for comprehensive raw milk quality assessment.