Download - Ghent University Laboratory of Chemical Analysis Dpt. Veterinary Public Health and Food Safety
KAREN BEKAERT
Ghent University
Laboratory of Chemical Analysis
Dpt. Veterinary Public Health and Food Safety
Faculty of Veterinary Medicine
The use of the hot iron method for the detection of boar taint
Prof. L. Vanhaecke
Dr. F.A.M. Tuyttens
F. Vandendriessche
OUTLINE
• CURRENT SITUATION
• OBJECTIVES
• PRELIMINARY RESULTS
• TAKE HOME MESSAGES – FUTURE PERSPECTIVES
2 K.M. Bekaert – BOARS FOR 2018
OUTLINE
• CURRENT SITUATION
• OBJECTIVES
• PRELIMINARY RESULTS
• TAKE HOME MESSAGES – FUTURE PERSPECTIVES
3 K.M. Bekaert – BOARS FOR 2018
CURRENT SITUATION
CURRENT SITUATION
HOT-IRON METHODSubjective method but
“easy” to use in slaughterhouseand gains fast results
Used by:Researchers
SlaughterhouseNO RESEARCH ON IMPORTANT CHARACTERISTICS
e.g. habituation, intra - and interreliability, position on the carcass, location in the slaughterhouse or in the laboratory
K.M. Bekaert – BOARS FOR 20184
• EXPERTS
CURRENT SITUATION
CURRENT SITUATION
• HOT-IRON
• USE OF THE HOT-IRON• First singe the fat and afterwards smell• Singe the fat and smell at the same time
HabituationType of hot-iron – temperature of the room/ fat
K.M. Bekaert – BOARS FOR 20185
OUTLINE
• CURRENT SITUATION
• OBJECTIVES
• PRELIMINARY RESULTS
• TAKE HOME MESSAGES – FUTURE PERSPECTIVES
6 K.M. Bekaert – BOARS FOR 2018
“Evaluation” of the hot-iron method
» Technical aspects» Heating methods» Cleaning» Singeing» Inter variability between experts» Intra variability of the experts» Habituation» Distribution of the compounds in the carcass
OBJECTIVES
OBJECTIVES K.M. Bekaert – BOARS FOR 20187
OUTLINE
• INTRODUCTION
• OBJECTIVES
• PRELIMINARY RESULTS
• TAKE HOME MESSAGES – FUTURE PERSPECTIVES
8 K.M. Bekaert – BOARS FOR 2018
• EXPERTS:
• SAMPLES: – Select and collect in slaughterhouse – Stored at -20°C
• HEATING METHODS:– Hot-iron– Pyropen
MATERIAL AND METHODS
K.M. Bekaert – BOARS FOR 20189
• SCORING: – Hot - iron• Continous
• Converted to 0-100 scale– Laboratorium analyses
strongpoor medium
no odour strongest imaginable
MATERIAL AND METHODS
K.M. Bekaert – BOARS FOR 201810
• TECHNICAL ASPECTS– SAMPLES: 30 samples– HEATING METHODS
A. HOT-IRON: 1. Wattage: 30 – 40 – 50 – 80 2. Brand: Ersa
B. PYROPEN: Setting 1 & 3
– CONDITIONSA. Temperature of the sample: room or refrigeratorB. Temperature of the area: room of refrigerator
MATERIAL AND METHODS
TECHNICAL ASPECTS K.M. Bekaert – BOARS FOR 201811
TECHNICAL ASPECTS
TECHNICAL ASPECTS
Maximum temperature
Theoretical(°C)
Measuring at room
temperature (22°C ± 1°C)
Measuring at refrigerator
temperature (5°C ± 1°C)
Hot-iron 30W 380 281 212
Hot-iron 40W 420 328 285
Hot-iron 50W 400 373 321
Hot-iron 80W 410 405 348
Pyropen 350 – 500(setting 1-5)
455(setting 3)
371(setting 3)
374(setting 1)
328(Setting 1)
K.M. Bekaert – BOARS FOR 2018
TEMPERATURE DROPS BY MOVING THE HOT-IRON
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Measuring at room temperature (22°C)
Measuring at refrigerator temperature (5°C)
Sample at room temperature (22°C°)
Sample at refrigerator temperature (8°C)
Hot-iron 30W3.6 3.9 4.3 sec45 40 32 °C
Hot-iron 40W2.1 2.6 2.7 sec40 34 28 °C
Hot-iron 80W Burned Burned Burnedsec°C
Pyropen (setting 1)2.5 2.7 4.1 sec43 36 30 °C
Pyropen (setting 3) Burned2.5 2.9 sec30 26 °C
TECHNICAL ASPECTS
TECHNICAL ASPECTS K.M. Bekaert – BOARS FOR 201813
• COMPARISION BETWEEN EXPERTS– Time of scoring• First singe the fat and afterwards smell
» For every hot-iron same time (3.4 sec ± 0.5)• Disadvantage: easier to burn the fat
• Singeing the fat and smell at the same time» Time depends on hot-iron wattage» Small differences between experts (± 0.5 sec)
TECHNICAL ASPECTS
K.M. Bekaert – BOARS FOR 2018TECHNICAL ASPECTS 14
• HEATING METHODS– SAMPLES: 32 samples– HEATING METHODS
A. MicrowaveB. Hot-iron: 30 WC. Pyropen: setting 3D. Pyropen + plate: setting 3
– CONDITIONS• Temperature of the sample and area: room
MATERIAL AND METHODS
K.M. Bekaert – BOARS FOR 2018HEATING METHODS 15
FRIEDMAN TEST
PAIRWISE COMPARISON
(CORRELATION)
strongpoor medium
no odour strongest imaginable
P<0.001P1 P2 M HI
*
Microwave Hot-iron Pyropen
Hot-iron 0.43
Pyropen 0.53 0.50
Pyropen+plate 0.50 0.52 0.46
HEATING METHODS
P1: pyropen; P2: pyropen+plate; M: microwave; HI: hot-iron
K.M. Bekaert – BOARS FOR 2018HEATING METHODS 16
K.M. Bekaert – BOARS FOR 2018HEATING METHODS
KENDALL’S CORRELATION COEFFICIENTMicrowave Hot-iron Pyropen Pyropen+plate
Indole 0.26 * 0.39 ** 0.38 ** 0.20
Skatole 0.25 * 0.40 ** 0.36 ** 0.16
Androstenone 0.34 ** 0.37 ** 0.34 ** 0.35 **
HEATING METHODS
Significant (* 0.05<p<0.01; ** 0.001<P<0.01)/ not significant
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• CLEANING– SAMPLES: 120 samples– HEATING METHODS
• Hot-iron: 30 W– CONDITIONS
• Temperature of the sample and area: room
– METHODS• Cleaning the hot-iron with paper/ethanol• Not cleaning the hot iron
MATERIAL AND METHODS
CLEANING K.M. Bekaert – BOARS FOR 201818
• CLEANINGSIGNED
RANK TEST
KENDALL’S CORRELATION COEFFICIENT
strongpoor medium
no odour strongest imaginable
P<0.001cleaning not cleaning
Cleaning Not cleaning
Indole 0.48 0.31
Skatole 0.48 0.29
Androstenone 0.30 0.27
CLEANING - SINGEING
K.M. Bekaert – BOARS FOR 2018CLEANING
p<0.001
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• SINGEING– SAMPLES: 120 samples– HEATING METHODS
• Hot-iron: 30 W– CONDITIONS
• Temperature of the sample and area: room– SINGEING ONE FAT SAMPLE TWO TIMES AT THE SAME
PLACE
MATERIAL AND METHODS
1 and 2 singeing
SINGEING K.M. Bekaert – BOARS FOR 201820
• SINGEINGSIGNED
RANK TEST
KENDALL’S CORRELATION COEFFICIENT
strongpoor medium
no odour strongest imaginable
P<0.01firstsecond
First second
Indole 0.49 0.30
Skatole 0.43 0.31
Androstenone 0.25 0.26
CLEANING - SINGEING
K.M. Bekaert – BOARS FOR 2018 SINGEING
p<0.001
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OUTLINE
• CURRENT SITUATION
• OBJECTIVE
• PRELIMINARY RESULTS
• TAKE HOME MESSAGES – FUTURE PERSPECTIVES
22 K.M. Bekaert – BOARS FOR 2018
TAKE HOME MESSAGES
TAKE HOME MESSAGES – FUTURE PERSPECTIVES
K.M. Bekaert – BOARS FOR 2018
• CHOICE OF HEATING METHOD– Significant difference between the methods– Highest values for microwave and hot-iron– Good correlation between the methods– Hot-iron and pyropen best correlation with compounds
• USE OF THE HOT-IRON– Carefully choose wattage (room and sample temperature)– Necessary to clean the hot-iron– Never singe on the same place
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• Inter- and intra-variability of the experts statistics
• Variation of the concentration of indole, skatole and androstenone inside a carcass
FUTURE PERSPECTIVES
TAKE HOME MESSAGES – FUTURE PERSPECTIVES
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• Agency for Innovation by Science and Technology (IWT-Vlaanderen)
• Imperial Meat Products VOF
• VION Food Group (NL)
THANKS TO
THANKS TO K.M. Bekaert – BOARS FOR 201825
THANKS TO
THANKS TO K.M. Bekaert – BOARS FOR 201826
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K.M. Bekaert – BOARS FOR 201827