Common methods of analysis for meat and poultry products

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Common methods of analysis for meat and poultry
products

• Water
• AOAC
• 1. Oven drying
• weigh 2 - 5g. into cellulose thimbles or aluminum
  pans
• dry at 100 - 102oF for 16 - 18 hrs.
• cool in dessicator
• reweigh
• weight lost calculated and reported 2000

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AOAC oven options

• 2. - convection at 125oF for 2 - 4 hrs.
• 3. - vacuum at 95 - 100oF for 8 - 12 hrs.
• 4. - microwave at 80 - 100 power for 3
  - 5 minutes
• Note special design (CEM Corp.) -
  30,000

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Rapid methods - water

• 1. Rapid heating / balances
• Ohaus, Mettler, others - infrared, halogen,
  microwave sources of heat
• 15 - 30 minutes
• 1000
• 3-4

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METTLER LJ16 Moisture Analyzerfor rapid and
simple routine drying
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2. Near infrared transmission (NIT)

• NIR common for grain
• Must be calibrated
• Nondestructive, multi-component measurement
• Now available for in-line use
• 40,000 - 60,000

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Near infrared (NIR)

• Broad, multiple component analyses
• Measurement of near infrared absorption by
  functional organic groups ketones, alcohols,
  esters, ethers, aldehydes, etc.
• fingerprints pure compounds, mixtures must be
  calibrated to known standards
• calibration is critical
• Transmission (as opposed to reflectance)
  instruments show very good performance

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Near infrared (NIR) (continued)

• Cost is 50,000 for table top instruments
• Measurement time lt 1 second
• Continuous monitoring of composition on
  commercial mixers and grinders

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INFRATEC?tecator 126
5 MEAT ANALYZER
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CFS MultiTrack/Wolfking Continuous Fat Analyzer

• Gives simultaneous measures of fat, water and
  protein
• 20 measurements per minute

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• Wolfking indicates SD of 0.3
• Cost is 95,000

• from CFS (Wolfking) technical literature

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3. Guided microwave spectrometry (GMS)

• Similar strengths and weaknesses as NIT but not
  as well established
• Nondestructive, multi-component, in-line use

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Guided microwave spectrometry (GMS)

• Microwave absorption to measure changes in
  conductivity and dielectric constants
• Available for in-line measurements (GMS 44)

and on grinders (GMS 46) from Weiler
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Guided microwave spectrometry (GMS) (continued)

• Multi component measurements including salt and
  temperature
• Fat at 2 measurements per second
• 25,000 lbs/hr on grinders
• SD indicated by Weiler as 0.2-0.4
• Matrix sensitivity to air and to ice crystals
• Cost is 115,000

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Fat

• AOAC
• 1. Ether extract (Soxhlet)
• dried 2 -5 g. sample
• extract with di-ethyl ether or petroleum ether
  (hexane) --- 8 - 12 hrs.
• cool in dessicator, reweigh
• calculate fat as weight lost of wet sample
  weight
• does not include phospholipids

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2. Specific gravity - Fosslet

• Extract with tetrachloroethylene in orbital
  shaker
• Extract measured for specific gravity and
  converted to fat 10 minutes

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3. Microwave / solvent - CEM

• Dried samples extracted with methylene chloride
  in special CEM container - 4 minutes
• Weight lost expressed as fat

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Rapid methods - fat

• 1. Cooked / fat release
• Hobart - only for fresh ground beef
• 15 minutes
• good as a guess

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Rapid methods product formulation

• Hobart F-101

• Heat rendering
• Highly variable, SD 2 or more
• Cost 1000

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2. Modified Babcock

• Acid digestion, release fat
• Measure fat layer
• Calibrated bottle for 9 or 18 g. samples

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Modified Babcock

• Acid hydrolysis, volumetric measurement
• Sensitive to variations in samples and procedure
• Capable of SD of 0.75
• Cost 7.00/bottle plus centrifuge

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3. X-ray absorption - Anyl-Ray

• 13 lb. sample
• Nondestructive

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4. Visual image analysis

• Computerized scan of surfaces for white fat
  exposed

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Supercritical fluid extraction

• CO2 at elevated pressure and temperature
• Fast (20-30min), no solvent residue
• Matrix-sensitive, moisture absorbers may need to
  be included with samples
• Performance can be good but may be affected by
  sample matrix

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Comparison of Supercritical Fluid Extraction
(SFE) and Soxhlet Extraction
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• Instruments available from LECO and others

• Cost 30,000

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Q C Assistant

• Software by Least Cost Formulations, LTD
• fat from database predicted by water content
  (indirect)
• Licensed for 3,000
• Offered with CEM microwave oven for moisture
  (AOAC approved) as Profat 2 ?

• SD of 0.5 - 0.7
• Cost 21,000

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NMR

• Newest innovation in fat analyses
• Based on proton response to oscillating magnetic
  field, similar to magnetic resonance imaging
  (MRI) used for medical applications
• Water typically causes interference
• CEM microwave oven plus NMR
• Smart Trac ?

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SMART Trac ?

• results in 4-5 minutes
• no solvents
• no calibration
• direct measure of fat
• effective over wide range
• cost 65,000

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Hot Dogs-Regular

• Sample Moisture Calculated
• ID
  () Fat
• 1 51.11 30.89
• 2 51.32 30.93
• 3 51.37 30.85
• 4 51.21 30.72
• 5 51.24 30.67
• Average 51.25 30.81
• Standard Deviation 0.101 0.112
• 30.79 Reference Fat from Soxhlet
• - from CEM technical literature

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Additional methods

• Ultrasound
• In beef, intramuscular fat correlation was
  reported as about 0.88 with standard errors of
  about 0.8
• In pork, correlations appear to be about 0.5-0.7
• May be useful for live measurement
• Electrical conductivity (TOBEC)
• Not widely applied beyond carcasses and primals.

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Advanced Methods for fat

• Caviezel
• Total lipid measured as total fatty acids
• Includes triglycerides, phospholipids, sterols,
  free fatty acids
• Meets FDA definition of total fat for labeling
• N-butyl alcohol extraction, saponification,
  separation, quantitation by GC
• AOAC peer-verified status
• Correlation coefficients of 0.99, SD of 0.47
  reported

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Advanced Methods for fat

• Caviezel (continued)
• Automated system available from Büchi

• Requires about 2 hours
• Cost 88,000 (55,000 for manual
  sampling)

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Measurement of Fat in Meat with Caviezel Method
and Büchi System

• Number of Caviezel measurement as
  Product samples of official method
• Raw meat 5 103.7
• Cooked sausage 13 101.9
• Uncured sausage 14
  101.7
• Cooked, cured meats 9 105.0
• Sausage with vegetable fat 5
  99.3
• - from Büchi technical literature

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Protein

• AOAC
• 1. Kjeldahl - developed in 1883
• acid digest to NH4 for N content
• calculate protein as N x 6.25
• - Beware -

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2. Combustion - developed in 1970s

• 800 - 900o C oven to convert protein to N2
• Measures N2 by thermal conductivity
  again, calculate protein as N x 6.25
• No waste products
• Sample preparation critical due to small sample
  size

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3. CEM Sprint Rapid Protein Analyzer

• Introduced Jan., 2008
• Specific protein tagging solution with
  colorimetric(?) measurement
• Direct protein measure, avoids false high values
  from nonprotein nitrogen, i.e. melamine in pet
  foods, milk products
• AOAC approved

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Rapid methods - protein

• Can estimate protein given results for water and
  fat
• assume 1 ash for fresh meat
• 2 - 4 ash for processed meat depending on
  specific product

By Or use M P ratios if
appropriate (fresh meat M P
3.7 1)
W F P A 100
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Ash

• AOAC
• 5 g. sample weighed into crucible
• 550oC ( 900oF - 1000oF) oven for 8 - 12 hrs.
• Remaining weight (after cooling) is mineral or
  ash of original sample weight
• Relatively constant at about 1 for fresh meat
• Salts (i.e. processed meats) increase ash content

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For analytical methods at any level,

• Remember performance
• Know method capability
• Monitor for deviations during use

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Other methods for 460 products

• 1. Salt
• Quantab indicating strips AOAC - however -
  precision 10
• 10 g. sample 90 ml hot water
• cool, insert strip, read when finished
• remember dilution factor i.e. 0.24 x 10 2.4

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2. pH

• Measure of H ion concentration or acidity
• pH - log H log relationship means that pH
  4 is 10x as acidic as pH 5 and 100x as pH 6
• Cannot numerically average pH values pH 4 pH
  5 ? pH 4.5 2

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3. Color / sensory
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Ten replicates were analyzed on 10 different days
with with 5 different standard reference
materials in the submitting laboratory. Each
result represents the average of 2 injections.

• Sample CRM 384 was pork

from Pendl et al., 1998
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Performance of NIT Measurements Relative to AOAC
International Methods for Meat Products
from Sebranek, 1996
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Analytical Values for Fat in Pork Using AOAC
International and NIR Methods
from
King-Brink, et al., 1996
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Pork

• Sample Moisture Calculated
• ID
  () Fat
• 1 74.74 3.38
• 2 74.58 3.44
• 3 74.67 3.35
• 4 74.78 3.31
• 5 74.63 3.33
• 6 74.69 3.39
• 7 74.67 3.30
• 8 74.68 3.34
• 9 74.75 3.31
• 10 74.61 3.35
• Average 74.68 3.35
• Standard Deviation 0.06 0.04
• 3.33 Reference Fat from Soxhlet
• 73.85 Reference Moisture from Oven
• - from CEM technical literature

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Pork

• Sample Moisture Calculated
• ID
  () Fat
• 1 50.24 33.89
• 2 50.35 33.77
• 3 50.43 33.74
• 4 50.13 34.26
• 5 50.27 33.95
• 6 50.34 33.89
• 7 50.29 33.97
• 8 50.31 33.91
• 9 50.37 34.11
• 10 50.25 33.86
• Average 50.30 33.94
• Standard Deviation 0.08 0.154
• 33.79 Reference Fat from Soxhlet
• 50.01 Reference Moisture from Oven
• - from CEM technical literature

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Pork Sausage

• Sample Moisture Calculated
• ID
  () Fat
• 1 77.35 1.30
• 2 77.39 1.22
• 3 77.39 1.23
• 4 77.38 1.24
• 5 77.33 1.36
• 6 77.37 1.22
• 7 77.19 1.26
• 8 77.30 1.24
• 9 77.16 1.31
• 10 77.18 1.29
• Average 77.30 1.27
• Standard Deviation 0.09 0.05
• 1.30 Reference Fat from Soxhlet
• 77.35 Reference Moisture from Oven
• - from CEM technical literature

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Pork Sausage

• Sample Moisture Calculated
• ID
  () Fat
• 1 46.78 38.99
• 2 46.58 39.47
• 3 46.58 39.24
• 4 46.64 39.15
• 5 46.68 38.90
• 6 46.71 39.26
• 7 46.59 39.30
• 8 46.67 39.42
• 9 46.35 39.55
• 10 46.74 39.14
• Average 46.62 39.24
• Standard Deviation 0.12 0.21
• 39.24 Reference Fat from Soxhlet
• 46.62 Reference Moisture from Oven
• - from CEM technical literature

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Hot Dogs-Light

• Sample Moisture Calculated
• ID
  () Fat
• 1 64.23 15.63
• 2 64.34 15.60
• 3 64.35 15.54
• 4 64.44 15.67
• 5 64.49 15.83
• 6 64.25 15.87
• Average 64.35 15.69
• Standard Deviation 0.102 0.132
• 15.71 Reference Fat from Soxhlet
• - from CEM technical literature

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5. Electrical conductivity - Emme

• Ultrasonics - live animal uses
• Near infrared (NIT) and guided microwave
  spectrometry (GMS)

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Comparison of Selected Fat and Moisture Analysis
Methods