Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 1

Determination of calcium by EDX

a fast method for the determination of mechanically recovered meat (MRM)

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 2

What is mechanically recovered meat?

EC Regulation No 853/2004 (Annex I): “…the product obtained by removing meat from flesh-bearing bones after boning or from poultry carcasses, using mechanical means resulting in the loss or modification of the muscle fiber structure”

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 3

Production of mechanically recovered meat

Various methods for separating bones from MRM

Drum-belt separator Endless screw separator

Images from EFSA Journal, 2013, 11.

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 4

Bone fragments

• Mechanically recovered meat contains small bone fragments

Image from P. Komrska et al. , Acta univ. agric. et silvic. Mendel. Brun., 2010, 59, 145-152

MRM stained with Alizarin Red and Trichrome Green

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 5

Analytical implications

• Calcium can be used as marker element for MRM:

• Ca content of bone ash is constant (36.3 – 36.9 % Ca)[1]

• Low Ca concentration in meat

• Samples will be heterogeneous

• Homogenization of a larger sample mass prior subsampling

[1] C. Blincoe, A. L. Lesperance and V. R. Bohman, Journal of Animal Science, 1973, 36, 971-975

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 6

Regulatory requirements

• EC Regulation No 2047/2005

• Ca in MRM “shall not exceed 0,1 % of fresh product”

• Austrian food codex, Chapter B14

• MRM mustn’t be used for the production of sausages

• Ca content < 200 mg/kg if bone particles are present

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 7

“Traditional” way of analyzing Ca

Sample

homogenization

Digestion in

acid (HNO3)

Ca quantification

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 8

Alternative approach: EDX

Sample

homogenizationCa quantification

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Determination of Ca

• Samples

• 3 different types of sausages

• Liver meat paste

• Dog food

• Homogenization

• Büchi Mixer (500 g batches)

• Retsch Cryo Mill for homogeneity studies

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 10

EDX: Ca determination

• Gravimetrically prepared standards in the range of 400 – 1600 mg kg-1

• Standard conditions for Ca in the Shimadzu EDX 8000

• Collimator: 10 mm

• Integration time: 100 s

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EDX: Ca calibration

Professor Horst Cerjak, 19.12.2005Wiltsche Helmar 12

EDX: Ca determination

• EDX limit of quantification (LOQ): 170 mg kg-1

• Reference digestions and Ca-quantification of several samples (sausages and pet food) by ICP-OES

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Comparison EDX / classical approach

Sample Reference value (ICP-OES) EDX

Sausage (Krakauer) 42 ± 1 mg/kg < LOQ (160 mg/kg)

Sausage (Huber) 52 ± 2 mg/kg < LOQ (160 mg/kg)

Sausage (Tann) 48 ± 1 mg/kg < LOQ (160 mg/kg)

Liver meat paste (Inzersdorfer) 83 ± 2 mg/kg < LOQ (160 mg/kg)

Dog food (Pedigree) 2610 ± 80 mg/kg 2690 ± 70 mg/kg

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Spike concentration: 1000 mg kg-1 Ca

EDX: Spike recovery

0

20

40

60

80

100

120

140

160

Sausage(Krakauer)

Sausage(Huber)

Sausage(Tann)

Liver meatpaste

(Inzersdorfer)

Dog food(Pedigree)

Spik

e re

cove

ry, %

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Conclusion: Spike recovery

• Spike recoveries in general acceptable – potential problems with the homogenization of the Ca-standard into the sample

• relatively high RSD’s for EDX

• some samples were particularly rich in fat

• Sample heterogeneity was troublesome in ICP-OES

• although some sausages “look” homogeneous, they aren’t!

• Production of the sausages can have an effect on the distribution of the raw materials

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Time required for an analysis

“Traditional” approach:

Acid digestion and ICP-OES

• digestion of 16 samples 60 min

• ICP-OES: 60 min (including calibration)

about 7-8 min per sample

EDX

less than 2 min per sample

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Conclusion

• EDX provides a fast and reliable method for screening meat products

• LOQ sufficient for Austrian food codex (and similar regulations throughout the EU) identification of products potentially containing MSM

• Requirements of EC Regulation No 2047/2005 are easily fulfilled in terms of LOQ

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Acknowledgements

• Shimadzu

• Florian Zand and Herbert Motter

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Thank you for your attention!