Table 4.
Determination of the presence of walnut in commercially processed food products using multimeric scFv ELISA, Alertox® Walnut ELISA kit, and real time PCR.
| Label Statement | Product | Number of Samples | Multimeric scFv ELISA | Walnut Kit Alertox® | ITS Real Time PCR |
|---|---|---|---|---|---|
| Walnut declared as ingredient | Biscuit Nut bar Breakfast cereals Chocolate Sauce Bread Beverage Ice cream Snack Yoghurt Sandwich |
5 5 1 2 1 3 1 1 1 5 2 |
+(5) +(5) +(1) +(1)/−(1) −(1) +(3) −(1) −(1) +(1) −(5) +(1)/−(1) |
+(5) +(5) +(1) +(1)/−(1) +(1) +(3) +(1) +(1) +(1) +(5) +(2) |
+(5) +(5) +(1) +(1)/−(1) +(1) +(3) +(1) +(1) +(1) +(5) +(2) |
|
May contain
walnut |
Chocolate Yoghurt |
1 1 |
−(1) −(1) |
−(1) −(1) |
−(1) −(1) |
| Contains other tree nuts | Biscuit Nut bar Breakfast cereals Chocolate Breadstick Beverage Ice cream |
4 9 10 2 1 2 2 |
−(4) −(9) +(5)/−(5) −(2) −(1) −(2) −(2) |
−(4) −(9) +(7)/−(3) −(2) −(1) −(2) −(2) |
−(4) −(9) +(6)/−(4) −(2) −(1) −(2) −(2) |
| May contain tree nuts traces | Biscuit Nut bar Breakfast cereals Chocolate Beverage Ice cream |
6 5 3 10 1 1 |
−(6) −(5) −(3) −(10) −(1) −(1) |
−(6) −(5) −(3) +(2)/- (8) −(1) −(1) |
−(6) −(5) −(3) +(3)/−(7) −(1) −(1) |
| Not declaring nuts or traces as ingredient | Biscuit Nut bar Breakfast cereals Chocolate Sauce Bread Beverage Ice cream Snack |
3 1 3 1 1 1 2 2 1 |
−(3) −(1) −(3) −(1) −(1) −(1) −(2) −(2) −(1) |
−(3) −(1) −(3) −(1) −(1) −(1) −(2) −(2) −(1) |
−(3) −(1) −(3) −(1) −(1) −(1) −(2) −(2) −(1) |
Commercial food products showing estimated walnut concentration lower than the limit of detection (LOD) in ELISA methods, or below 0.1 mg kg−1 in PCR, were considered negative. The number in the basket is the number of samples.