title: Harmonization of methods for analysis of cholesterol oxides in foods--the first portion of a long road toward standardization: interlaboratory study.
abstract: A compilation of literature data on the content of cholesterol oxidation products (COP) in various food products and in blood demonstrates a large variation in content in products or tissues of very similar nature when analyzed in different laboratories according to a large number of methods. The lack of validated, internationally recognized methodology with published accuracy and precision has so far hindered such assessments. Hence an interlaboratory comparision of methodologies of COP analysis was undertaken on egg yolk powders (EYP), whole milk powders (WMP), skim milk powders (SMP), and lard (L). Each product type had one fresh sample (low) and one aged (high) in COP contents. A total of 17 sets of results on WMP, 15 on SMP and EYP, and 13 on L were compared. Overall results (mg/kg sample) varied extensively: Fresh EYP 0.72-265, aged EYP 2.51-361; fresh WMP 0.02-18.1, aged WMP 0.02-26.9; fresh SMP 0.02-6.51, aged SMP <0.01-6.51; fresh L 0.18-97, aged L 4.15-452. Some results were questioned, viz., those from laboratories not indicating substantial differences between samples "low" and "high" in total COP. Others were excluded because of lack of verification of identity of gas chromatographic peaks by mass spectrometry. Then a more narrow range of core results (mg/kg sample) was observed: Fresh EYP 5.69-29.5 sample, aged EYP 11.8-79.0; fresh WMP 0.12-1.76, aged WMP 1.17-13.7; fresh SMP <0.30-<1.21, aged SMP 0.30-2.26; fresh L 0.18-5.07, aged L 94.4-231. At a workshop discussing the results, numerous recommendations were made toward more reliable methodology for determination of COP in foods.
authors.affiliation: Swedish University of Agricultural Sciences, Department of Food Science, PO Box 7051, SE-750 07 Uppsala, Sweden. Lars-Ake.Appelqvist@lmv.slu.se
authors.forename: Lars-Ake
authors.initials: LA
authors.lastname: Appelqvist
authors.forename: Paul
authors.initials: P
authors.lastname: Addis
authors.forename: Ingemar
authors.initials: I
authors.lastname: Björkhem
authors.forename: Jacques Olivier
authors.initials: JO
authors.lastname: Bosset
authors.forename: Maria Fiorenza
authors.initials: MF
authors.lastname: Caboni
authors.forename: Paresh
authors.initials: P
authors.lastname: Dutta
authors.forename: Andre
authors.initials: A
authors.lastname: Grandgirard
authors.forename: Fransesc
authors.initials: F
authors.lastname: Guardiola
authors.forename: Lung-Bin
authors.initials: LB
authors.lastname: Hau
authors.forename: Jacob Holm
authors.initials: JH
authors.lastname: Nielsen
authors.forename: Antony
authors.initials: A
authors.lastname: Hugget
authors.forename: Lucy Sun
authors.initials: LS
authors.lastname: Hwang
authors.forename: Jorma
authors.initials: J
authors.lastname: Kumpulainen
authors.forename: Sinead
authors.initials: S
authors.lastname: McCluskey
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ohshima
authors.forename: Roman
authors.initials: R
authors.lastname: Przbylski
authors.forename: Alex
authors.initials: A
authors.lastname: Sevanian
authors.forename: Pearlly
authors.initials: P
authors.lastname: Yan
mesh_terms: D002784:Cholesterol / Q000378:metabolism*; D005504:Food Analysis / Q000592:standards*; D007753:Laboratories; D008055:Lipids / Q000032:analysis; D010087:Oxides / Q000032:analysis
chemical_list: D008055:Lipids; D010087:Oxides; D002784:Cholesterol