Walnut ELISA Kit

Full Name: Walnut ELISA Kit
Sample Type: Food (Chocolate, Cereals, Ice Cream)
Sensitivity: 0.35 ppm


A nut from any tree in the Juglans genus and family, particularly the Juglans regia, is referred to as a walnut. Walnuts are one of the main ingredient of Fesenjan (Iranian cuisine), they are also used in making brownies, garnish on some foods and ice cream toppings. It is a nutrient-dense with protein and many fatty acids, the fraction of protein present in walnuts is relatively high (approx. 15%). Many of these proteins are found to be responsible for causing allergic reactions (for example rJug r1 and rJug r4), even the consumption of small quantities of walnut can lead to allergic responses and in severe cases result in causing anaphylactic shock.

Many of these nuts are also heat resistant and this property makes them stable during many different production processes, this makes walnut a crucial food allergen. This explains why in a number of cases the presence of walnut residues in many food cannot be excluded. It is highly recommended to avoid eating any walnuts or walnut containing food if a person is known to have an allergy.


Walnut ELISA kit can be used for analysing quantitative levels of walnut residues in food (such as chocolate, ice cream and cereals). This assay has a minimum analytical sensitivity limit of 0.35 ppm.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Microtiter Plate: Coated with anti walnut antibodies.
  • Walnut Standards 1-5: Concentration 0, 2, 6, 20, 60 ppm.
  • Conjugate (Anti-Walnut-Peroxidase).
  • Substrate Solution (TMB).
  • Stop Solution (0.5 M H2SO4).
  • Extraction and sample dilution buffer (Tris)(10x).
  • Washing Solution (PBS + Tween 20)(10x Concentrate).
  • Instruction Manual.


The minimum detection sensitivity level of walnut residues using current walnut ELISA kit was 0.35 ppm. The standard range for this assay is 2.0 – 60.0 ppm.


– Sensitivity: Limit of detection, LOD (0.35ppm), Limit of quantification, LOQ (2.0ppm)
– Specificity (Cross Reactivity): Pecan (0.0005%), Cashew, Chicken (0.0003%). No cross reaction was detected for the following: Adzuki, Cayenne, Cow’s milk, Guar gum, Onion, Rice, Almond, Celery, Crab (cooked), Hazelnut, Paprika, Rye, Apricot, Cherry, Crab (raw), Isinglass, Pea, Saccharose, Barley, Chervil, Cress, Kidney bean, Peanut, Sesame, Bean (white), Chestnut, Cumin, Kiwi, Pepper, Shrimp (cooked), Beef, Chia, Duck, Lamb, Pine seed, Shrimp (raw), Bovine gelatine, Chickpea, Egg, Lentil, Pistachio, Soy flour, Brazil nut, Chili, Ewe’s milk, Lupin, Plum, Sunflower seeds, Buckwheat, Cocoa, Fenugreek, Macadamia, Poppy seed, Tomato, Caraway, Coconut, Fish gelatine, Mustard, Pork, Turkey, Carob gum, Cod, Gliadin, Nutmeg, Potato, Wheat, Carrot, Corn, Goat’s milk, Oats, Pumpkin seed.
– Intra-Assay Precision: 4 – 9%
– Inter-Assay Precision: 12%
– Linearity: 70 – 128%
– Recovery: Cereals (106%), Cookies (103%), Ice cream (86%), Chocolate (75%).


  1. Detection of walnut residues in foods using an enzyme-linked immunosorbent assay. J Food Sci. (2009) 74 (6): T51-7. Niemann L., et al.
  2. An acute intake of a walnut-enriched meal improves postprandial adiponectin response in healthy young adults. Nutr Res. (2013) 33 (12): 1012-8. Lozano A., et al.
  3. Development of an indirect competitive immunoassay for walnut_protein component in food. Food Chem. (2014) 147: 106-10. Wang H., et al.
  4. Detection by real time PCR of walnut allergen coding sequences in processed foods. Food Chem. (2016) 202: 334-40. Linacero R., et al.
  5. Walnut-induced anaphylaxis with cross-reactivity to hazelnut and Brazil nut. J Allergy Clin Immunol. (2004) 113 (2): 358-60. Asero R., et al.



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