Analysis of duplicate 24-hour diet samples for aflatoxin B₁, aflatoxin M₁and ochratoxin A

Abstract

In the spring and autumn of 1994, a total diet study, in which 123 participants collected duplicates of their 24-hour diets, was carried out. The goal of this study was to determine the mass fractions of a number of analytes in these duplicate diets, so as to be able to establish oral daily intake values. After measurements were carried out for pesticides, PCBs, elements, sterols, nitrate and nitrite, and fatty acids, the duplicate diet study was concluded with analyses for aflatoxin M1, aflatoxin B1 and ochratoxin A. For this purpose a method of analysis was developed, that could simultaneously determine these mycotoxins at very low levels. The method involved chloroform extraction, liquid-liquid extraction, immunoaffinity cleanup and liquid chromatography. The method was supplemented with a procedure to confirm the identity of chromatographic peaks, assumed to represent aflatoxin M1, aflatoxin B1 and ochratoxin A. The method was in-house validated. Recoveries ranged from 68-74% for aflatoxin M1 (at spiking levels from 30-120 ng/kg, c.v. 7.6%), from 95-97% for aflatoxin B1 (at spiking levels from 50-200 ng/kg, c.v. 2.8%), and from 75-84% for ochratoxin A (at spiking levels from 150-600 ng/kg, c.v. 4.3%). Limits of quantitation (defined as signal/noise = 10) were estimated to be 24, 5 and 16 ng/kg lyophilised material for aflatoxin M1, aflatoxin B1 and ochratoxin A respectively. The newly developed method was used to analyse 123 samples of 24-hour diets. Aflatoxin M1 was detectable in 48% of the samples; the toxin contents remained below the limit of quantitation in all samples. Aflatoxin B1 could be detected in 42% of the samples; in 25% of the samples the levels were above the limit of quantitation. Ochratoxin A could be quantified in all samples. The analytical results were further processed to estimate levels of intake. Intake levels for the aflatoxins were very low, and could not reliably be established. The mean ochratoxin A intake was estimated to be 1.2 ng/kg body weight per day. This is well below the tolerable daily intake established by JECFA at 14 ng/kg body weight per day. The current dietary intake of ochratoxin A in the Netherlands is concluded to pose no appreciable health risk.

Validation of a database on acrylamide for use in epidemiological studies

“…Information on gender, age and body weight of the participants was collected. The design and sampling procedure were the same as applied in an earlier duplicate diet study that was performed in 1994 by RIVM and described by Sizoo and van Egmond (2005). Duplicate 24-h food and drink portions, including drinking water, were collected during the two study periods each to take seasonal fluctuations in food composition and consumption into account.…”

Toxico-Pathological Effects of In Ovo Inoculation of Ochratoxin A (OTA) in Chick Embryos and Subsequently in Hatched Chicks

“…Total mycotoxin (aflatoxin B 1 [AFB 1 ] and OTA) contents of eggs was determined by HPLC (Sizoo and van Egmond 2005). For this purpose, a total of ninety eggs were selected and twenty pooled samples, each composed of five blended eggs, were prepared.…”

Trends in Diet and Exposure to Chemicals in Dutch Children

“…A duplicate diet study in adults performed in 1994 reported an average exposure of < 0.03 ng/kg bw per day for aflatoxin B 1 (N=123; Sizoo and Van Egmond, 2004), while a similar study carried out in 2004 showed a somewhat higher (median) exposure of 0.04 ng/kg bw per day (N=61; Van Egmond, 2006). As the variation was relatively high (e.g.…”