QUALITY ASSURANCE TOOLS IN MILK-TESTING LABORATORIES THE VIEW OF AN INSTRUMENT MANUFACTURER DR. DANIEL SCHWARZ, FOSS, DENMARK

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1 QUALITY ASSURANCE TOOLS IN MILK-TESTING LABORATORIES THE VIEW OF AN INSTRUMENT MANUFACTURER DR. DANIEL SCHWARZ, FOSS, DENMARK

2 INTERNATIONAL CERTIFICATIONS OF MILK ANALYSERS

3 Species Organisation(s) Standard(s) CONFUSION Parameter(s)

4 OVERVIEW ON INTERNATIONAL VALIDATIONS NCIMS (CNIEL) EU RL Somatic cell counting, payment Bacterial counting, payment (Milk composition analysis)

5 SOMATIC CELL COUNT EU RL Validation testing according to ISO , ISO , ISO (IDF 148-1, IDF 148-2, IDF 128-3) Item Fossomatic 7 Fossomatic FC ISO/IDF specification 1. Repeatability (r) in % per cell count level low (100 k) medium (500 k) high (1,500 k) Carry-over (CO) in % per cell count level low (500 k) CO H/L = 0.14; CO L/H = 0.48 CO H/L = 0.45; CO L/H = 0.28 < 2 medium (1,000 k) CO H/L = 0.07; CO L/H = 0.14 CO H/L = 0.21; CO L/H = 0.05 < 2 high (3,000 k) CO H/L = 0.05; CO L/H = 0.32 CO H/L = 0.13; CO L/H = 0.14 < 2 3. Linearity (r c ) in % Lower limit of quantification 17 k cells/ml 37 k cells/ml - 5. Upper limit of quantification k cells/ml k cells/ml - 6. Intra-laboratory reproducibility (R intra-lab ) in % per cell count level low ( k) medium low ( k) 9 19 medium ( k) medium high (651-1,000 k) 7 14 high (1,000-1,500 k)

6 SOMATIC CELL COUNT EU RL

7 SOMATIC CELL COUNT NCIMS Validation: correlation to reference method (i.e., microscopy (IDF 148-1)) 2400-form:

8 MILK COMPOSITION Validation testing according to ISO (IDF 128-3) and specifications of CNIEL Item 1. Accuracy (s y,x ) in g/l Milkoscan 7 RM Milkoscan FT+ IDF specificatio n Fat Protein Repeatability (S r ) in g/l Fat Protein Linearity (r c ) in % Fat Protein Carry-over (CO) in % Fat ND* 1 Protein ND* 1 5. Stability according to ISO yes yes *= not determined

9 BACTERIAL COUNT (EU RL AND NCIMS) Validation testing according to ISO , ISO , ISO Item BactoScan FC/FC+ ISO specification 1. Repeatability (r) log 10 cfu/ml < 0.25 log 10 cfu/ml 2. Carry-over (CO) 0.31 % < 1 3. Linearity (r c ) in % Lower limit of quantification 2.8 x 10 4 IBC/ml (9.6 k cfu/ml) 5. Limit of detection 10 k IBC/ml (3.8 k cfu/ml) 6. Upper limit of quantification 1.9 x 10 8 IBC/ml (2.9 x Accuracy (s y,x ) in range 1 x x 10 6 cfu/ml cfu/ml) 8. Interlaboratory repeatability 0.07 log 10 cfu/ml 0.28 log 10 cfu/ml <0.40 log 10 cfu/ml

10 NEW ICAR SERVICE: MILK ANALYSER CERTIFICATION Particular attention for DHI analyses The ICAR certification will follow the ICAR Protocol for evaluation of milk analysers and ISO (Milk Definition and evaluation of the overall accuracy of alternative methods of milk analysis) Harmonised protocol that serves the interest of milk recording world-wide avoid national certifications

11 SPECTRAL ANALYSIS OF MILK

12 FTIR ANALYSIS OF MILK SAMPLES Global models Global model Specific (i.e., local) models according to Scott et al., ICAR 2016 Annual

13 STANDARDISATION OF FTIR ANALYSERS Introduced in 1995 Based on running FTIR Equalizer (frequency: 1/month) Prerequisite for global transfer and application of calibrations

14 NEW PARAMETERS FOR MILK TESTING AND REFERENCE METHODS

15 EXAMPLE 1: KETOSIS SCREENING History: FTIR-based prediction of milk acetone (Hansen, 1999) FTIR-based prediction of milk β-hydroxybutyrate (deroos et al., 2007) β-hydroxybutyrate Concentrations: Milk urea: typically mmol/l Milk β-hydroxybutyrate: typically mmol/l Quality assurance as key to success when establishing ketosis screening service

16 FTIR BHB PREDICTION MODEL Indirect calibration developed: Absorbance Fingerprint area Protein BHB Requires raw milk Fat Wavenumber Correlation to wet-chemistry method: 0.82 (de Roos et al., 2007

17 QA PROGRAMME IN CANADA All laboratories offering ketosis screening participate in QA programme: Valacta, reference results (wet chemistry method) for 100 random samples Provision of BHB pilot samples Frequency: 1/month

18 QA PROGRAMME IN FRANCE All laboratories offering ketosis screening participate in QA programme: Reference laboratory, wet chemistry method 10 reference samples for BHB ( mmol/l) and 5 samples for acetone ( mmol/l) Frequency: 1/month

19 IDF GUIDELINE Action Team S03b: New applications of IR spectrometry Best practise cases on working with new FTIR-based parameters New guideline to be published in 2018

20 EXAMPLE 2: DIFFERENTIAL SOMATIC CELL COUNT Introduced in 2016 (Damm et al., 2017; Schwarz, 2017) Three types of immune cells in milk (e.g., Oviedo- Boyso et al., 2007): Lymphocytes Macrophages Polymorphonuclear neutrophils (PMN) Differential Somatic Cell Count (DSCC): Represents the combined proportion of the PMN and lymphocytes in percent The percentage of Macrophages is 100 DSCC Microscope spot, milk cells

21 THE FOSS DSCC METHOD SCC AND DSCC SIMULTANEOUSLY Analysis of SCC Analysis of DSCC FL 2 SCC (cells/ml ) FL 2 macrophages DSCC (%) PMN + lymphocytes FL 1 FL 1 SSC information used supportively for determination of SCC Damm et al., 2017; Schwarz, 201

22 IDF WORK Action Team S15: Bulletin on improvement of the reference method for somatic cell counting Possibilities/technologies for the SCC reference method including DSCC capability Bulletin to be published in 2018

23 A MESSAGE TO TAKE HOME Raw milk samples hold a wealth of information milk quality and dairy herd management new instruments and parameters FOSS supports quality assurance through Certification according to internationally-accepted standards Standardisation concept for FTIR analysers Development of guidelines/best practise cases for parameters where reference methods are not yet l