Immunochemical-based method for detection of hazelnut proteins in processed foods.
A competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect hazelnut by using polyclonal antibodies generated against a protein extract of roasted hazelnut. No cross-reactivity was observed in tests against 39 commodities, including many common allergens, tree nuts, and legumes. Hazelnut protein standard solutions at 0.45 ng/mL [inhibition concentration (IC80) of the competitive test] were clearly identified by the ELISA. An extraction and quantification method was developed and optimized for chocolate, cookies, breakfast cereals, and ice cream, major food commodities likely to be cross-contaminated with undeclared hazelnut during food processing. No sample cleanup was required when extracts were diluted 10-fold. Recovery results were generated with blank matrixes spiked at 4 levels from 1 to 10 microg/g hazelnut protein. With the developed extraction and sample handling procedure, hazelnut proteins were recovered at 64-83% from chocolate and at 78-97% from other matrixes. A confirmatory technique was developed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western transfer. The developed methods were applied to a small market survey of chocolate products and allowed the identification of undeclared hazelnut in these products.
Ben Rejeb
Samuel
S
Health Canada, Food Research Division, Bureau of Chemical Safety, Food Directorate, Health Products and Food Branch, PL 2203D, Ottawa, Ontario, Canada K1A 0L2. samuel_benrejeb@hc-sc.gc.ca
Abbott
Michael
M
Davies
David
D
Querry
Jessica
J
Cléroux
Chantal
C
Streng
Christine
C
Delahaut
Philippe
P
Yeung
Jupiter M
JM
D004797:Enzyme-Linked Immunosorbent Assay; D005504:Food Analysis; D009754:Nuts / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis*; D012680:Sensitivity and Specificity
D010940:Plant Proteins