Survey of Canadian human blood plasma for ochratoxin A

Abstract

Blood plasma samples collected from 144 healthy volunteers in 16 locations across Canada in 1994 were analysed for ochratoxin A (OTA). The method of analysis included cleanup by C18 solid phase extraction and immunoaffinity columns followed by liquid chromatography (LC) with fluorescence detection, which gave 86.5% (s.d. = 9.7) recovery (n = 31) of OTA (added at 2 ng/ml) with a detection limit of 0.15 ng/ml. The arithmetic mean concentration found in the plasma samples, corrected for volume of anticoagulant added, was 0.88 ng/ml with a standard deviation of 0.35 ng/ml and a range of 0.29-2.37 ng/ml. Confirmation of identity of OTA was by methyl ester formation for 65 samples and by LC-tandem mass spectrometry for 17 samples (some of which were included in pooled samples). Statistical analysis, by ANOVA of the log OTA plasma concentrations, showed a highly significant effect due to location in Canada (p = < 0.0001) but no effect due to age, sex or blood group of donors. The highest mean concentration was found in Winnipeg, significantly different (p = 0.05) by the Student-Newman-Keuls multiple range test from the lowest levels found in Toronto, Vancouver and Saint John.

Ochratoxin A contamination of cereal grains and coffee in Hungary in the year 2001

“…Studies surveying the OTA content of human blood samples have been performed in numerous countries of the world including Hungary, and such surveys have invariably detected a high rate of positivity (BreitholtzEmanuelsson et al, 1993;Kovács et al, 1995;Solti et al, 1997;Scott et al, 1998;Özcelik et al, 2001). In addition to the OTA contamination of human blood samples, the occurrence of ochratoxin in human colostrum has also been reported (Breitholtz-Emanuelsson et al, 1993;Kovács et al, 1995).…”

Biomarkers of human exposure to ochratoxin A

“…In a survey of human blood plasma in Canada, there was 100% incidence of OTA and a statistically significant greater mean concentration of OTA in samples from Winnipeg than in samples from Toronto, Vancouver and Saint John, New Brunswick (Scott et al 1998). In Switzerland, also with 100% incidence, men living south of the Alps had higher mean and median OTA concentrations in serum than men who lived north of the Alps (Zimmerli & Dick 1995).…”

“…Several studies -in Canada (Frohlich et al 1991, Scott et al 1998, Lebanon (Assaf et al 2004), Japan (Ueno et al 1998), Norway (Skaug 2003), Germany (Gareis et al 2000), northern Spain (Jiménez et al 1998), Italy (Tuscany) (Palli et al 1999) and Tunisia ) -found no difference with age in positive levels of OTA in human blood (adults). However, in a UK dietary exposure study (Gilbert et al 2001), plasma concentrations of OTA did appear to depend on age, with higher levels in 30-44 year-olds compared to <30 year-olds and >45 year-olds and this was significant for a screening sample taken 30 days before the start of the study.…”

“…Several studies -in Canada (Frohlich et al 1991, Scott et al 1998, Lebanon (Assaf et al 2004), Japan (Ueno et al 1998), Norway (Thuvander et al 2001, Skaug 2003, Sweden , Thuvander et al 2001, Germany (Gareis et al 2000, Hadlok 1993), Switzerland (Studer-Rohr et al 2000), northern Spain (Jimenez et al 1998), Hungary (Tápai et al 1997), the Czech Republic (Ruprich & Ostrý 1993b), Morocco (Filali et al 2002) and Tunisia ) -found no statistically significant gender differences in mean levels of OTA in human blood serum/plasma. In another study in Spain, Burdaspal and Legarda (1998) found 100% incidence of OTA in plasma and significant differences between men and women, with a greater mean OTA concentration in plasma for women in the summer (1.75 ng ml À1 vs. 1.12 ng ml À1 for men) and the converse in winter (0.97 ng ml À1 for women vs. 1.24 ng ml À1 for men).…”

“…In fact, urine concentrations showed a better correlation with OTA consumption than plasma concentrations. In addition to the above, mean daily intakes of OTA have been estimated from mean plasma/serum levels (all samples or positive samples) in studies on healthy humans in several other countriesCroatia (Peraica et al , 2001), Switzerland (Studer-Rohr et al 2000), the Czech Republic (Ruprich & Ostrý 1993a), Poland (Goliń ski et al 1991), Canada (Kuiper-Goodman et al 1993, Scott et al 1998, Japan (Ueno et al 1998), Lebanon (Assaf et al 2004), Algeria (Khalef et al 1993) and Morocco (Filali et al 2002) -and in healthy people and patients with Balkan endemic nephropathy in Bulgaria (Stoev 1998). Where blood concentrations have been reported, in order to relate these to serum concentrations another equation, which is derived from pig and human experimental data, is needed: Correlations between plasma OTA levels and specific types of food consumed have been shown for cereal products, wine, beer and pork in Norway and Sweden (Thuvander et al 2001) and for certain cereal products, sausages, red grape juice, chocolate with nuts and coffee in Germany (Gareis et al 2000).…”