The Occurrence of Ochratoxin A in Infant and Regular Oatmeal Cereal in the USA
Julie L Brunkhorst, Ryan J. Malone, Kelley M. Renkemeyer, Heather L. Henderson, Jordon S. Bierbaum, Jenny B. Buhr, Amy N. Pope, Nicole A. McKernan, Bruce R. Malone
Trilogy Analytical Laboratory, Washington, MO 63090
Ochratoxin A is a nephrotoxic and nephrocarcinogenic mycotoxin produced as secondary metabolites by several fungi of the Aspergillus and Penicillium species. This mycotoxin is regulated by many countries throughout the world. For example, the European Union regulation for Ochratoxin A in baby food is 0.5ppb and 3ppb for processed cereals and cereal products. The United States currently has no regulations or advisory levels for this mycotoxin. A limited survey was conducted of infant and regular oatmeal cereals that were purchased at retail stores from 9 different states in the USA. The samples were analyzed for Ochratoxin A using an UHPLC with fluorescence detection at a limit of detection at 0.05 ppb. Ochratoxin A was analyzed in 33 infant oatmeal samples and 90% were positive (greater than 0.05 ppb) with 64% of the samples found to be over the European regulation of 0.5 ppb with the highest concentration at 4.8 ppb. A total of 38 regular oatmeal samples (old fashioned oats, quick oats, etc.) were analyzed for Ochratoxin A with 79% of the samples positive (over 0.05 ppb) with the highest result being 4.8 ppb. A total of 10% of the regular oatmeal samples were over the 3ppb European regulation for processed cereals and cereal products. This data suggests that Ochratoxin A is a potential contaminant in oatmeal based products, including infant and regular oat cereals in the USA.
Samples of infant oatmeal (33) and regular oatmeal (38) were purchased at retail stores from 9 different US states. Each sample was analyzed for Ochratoxin A at a detection limit of 0.05ppb using UHPLC with fluorescence detection. The following methodology was used:
- Extract 25g sample with 100ml extraction solvent (3/1 methanol/water) by shaking for one hour.
- Dilute 16ml filtered extract with 64ml of PBS with 0.1% Tween 20
- The entire amount is added to an Ochratoxin immunoaffinity column (R-Biopharm Rhone).
- Rinse with 10ml water
- Elute with 2.0ml of methanol
- Evaporate and re-dissolve in Ochratoxin mobile phase
- Inject 10μl of standards and purified samples into the UHPLC system
- Fluorescence detector: excitation 333nm, emission 460nm
- Column: Shim-pack XR-ODS II 3.0 x 75mm 2.2 μm
- Mobile Phase: 45/54/1 Water/Acetonitrile/Acetic Acid
- Flow rate: 1.4ml/min
Ochratoxin A was analyzed by UHPLC using fluorescence detection and immunoaffinity purification.
- Accuracy: 0.05 ppb spike (84.8%), 0.50 ppb spike (85.2%), 5.0 ppb spike (89.5%)
- Precision (RSD): 0.05 ppb spike (10.1%), 0.50 ppb spike (9.4%), 5.0 ppb spike (5.5%)
- Linearity: 0.050 - 20.00 ppb
33 samples of infant oatmeal and 38 regular oatmeal samples were purchased from retail stores from 9 different US states and analyzed for Ochratoxin A.
Infant Oatmeal samples:
- 90.9% of the samples were positive (>0.05ppb)
- 63.6% of the samples were found greater than the EU limits for infant cereal (0.50ppb)
- Only 3 of the samples were found to be less than 0.05ppb
Regular Oatmeal samples:
- 78.9% of the samples were positive (>0.05ppb)
- 10.5% of the samples were found greater than the EU limits for cereal (3 ppb)
- 23.7% of the samples were found to be less than 0.05ppb
The data suggests that Ochratoxin A is a potential contaminant in oatmeal based products, including infant and regular oat cereals in the USA.