A human nose scoring system for boar taint and its implications for detection in a slaughter line Lourens Heres 1, Han Mulder 3, Egbert Knol 2, Saskia Bloemhof 2, Jan ten Napel 3, Bennie van der Fels 3, Pramod Mathur 2 (2) (1) (3)

Goal Explore the test characteristics of the human nose method – Reproducibility (between tester comparability) – Repeatability (within tester comparability) – Correlation with chemical methods – Sensitivity – Specificity Assess the consequences for in-line detection

Human Nose Detection method (HNS) Lab – Trained panelists – Electric soldering iron – In small room lab – at own speed, max 100 samples Slaughter line – Trained panelists – Flaming soldering Iron – In slaughter line – At slaughter speed – samples during an half hour

Critical elements for a certified in- line detection method 1. A documented procedure 2. Validated specification defining: sensitivity, specificity, repeatability and reproducibility, test time per individual animal, and operation time per tester. 3. Quality controls 4. Training 5. Separate logistic 6. Corrective and preventive measures 7. Feed-back to the farmer/sender. 8. Audits

Why The Human Nose? A low cost method with high through put – Tester employment costs under 1/test – Additional test for genetic selection A method that helps us in making progress – Feedback information for suppliers Supply management Feeding Genetic selection Practicable for breeding purposes and slaughter line detection – A method that fulfills the requirements of customers who buy pork (Dutch and German Retailers) – Applied at IPG/Topigs for breeding purposes

Materials and methods: 6574 entire males, different genetic lines Neck fat, divided into three pieces Stored vacuum, -18°C, maximum 6 months Each time ±100 samples were randomly selected heated by a soldering iron (Weller®, Catalog number W100PG, 100 Watt). – 370°C. – hot iron tip, 6 mm wide and 20 mm long, – about 2-3 seconds the volatiles were sniffed by the panelist Each piece tested by 3 panelists Androstenon and Skatol (ASI) for 5025 of the samples 9 panelists

Scoring system ScoreDescriptionDecision 0Normal pork smellNegative 1Deviant smell, but not boar taint 2Faint boar taint 3Boar taintPositive 4Strong boar taint

Laboratory panelist: selection and training Testers are sensitive to pure Androstenon and Skatol Instructions are given about the method Initial training by parallel testing and discussing the outcomes Statistical analyses took account of date of sampling (training effect)

Relation score and chemical components Source: Mathur et al. (2011) submitted to Meat Science Journal

Reproducibility: Correlation between testers Poly-choric correlation: taking into account the categorical nature of the data PanelistBCDEFGHI A B C D E F G H 0.45 Source: Mathur et al. (2011) submitted to Meat Science Journal Average = 0.39

Relationship HNS with boar taint compounds PanelistN Poly-serial correlations AndrostenoneSkatole A B C D E F G H I All Average Source: Mathur et al. (2011) submitted to Meat Science Journal

Accuracy (sensitivity & specificity) with androstenon and skatol as reference standard Sensitivity = True Positive tests / total positives acc. standard %positives detected Specificity = true negatives / total negatives acc. standard Cut offs: 1.0 µg/g for androstenone and µg/g for skatole Proportion above reference: – Andr. / Skatol: 44.0% – HNS: 8.7% PanelistSE(%)SP(%) A15,095,3 B12,097,7 C29,491,4 D17,196,4 E13,297,1 F17,999,7 G18,396,3 H15,799,3 I19,498,0 all16,197,1 Source: Mathur et al. (2011) submitted to Meat Science Journal

The True Boar taint 1000 All Boars 440 And / Skatol The Human Nose Se= 70/440 = 16% Sp= 544/560 = 97% Skatol/Androstenon Se= 70/86 = 81% Sp = 544/914 = 60% TN FN TPFP

Accuracy (sensitivity & specificity) with average-HNS-score as reference standard Average per boar Average HNS cut off = 2,5 PanelistSE (%)SP(%) A61,092,9 B79,195,6 C81,485,1 D81,693,0 E66,794,4 F72,298,3 G74,192,3 H75,895,8 I82,193,4 All75,493,7

The True Boar taint All Boars Tester x Average score = Reference Standard The Human Nose Score Se= 75% Sp= 93,7%

Conclusions Characteristics of the HNS-method/ASI-method & consequences for the implemented in-line HNS method : – Good correlations with the compounds – Good repeatability between testers – High number of false positives with Androstenon and Skatol: May falsely lead to undervaluation of the HNS test – False negatives with Androstenon and SkatoI – Low cost and faster speed than boar taint compounds – Close to consumer perception of boar taint – No increase of complaints or loss of sales is observed

Acknowledgements Panelists IPG and VION – Francien Arts, – Monique van Hilten, – Merel Bosman, – Brigitte Coenen, – Monique Willemsen, – Ilene Hattink, – Sharonne Martini – Marjo Liebers – Rebeca Polgar Ronald Crump Funds The European Community's Seventh Framework Programme FP7/ under grant agreement n°