RIDASCREEN®FAST Milk is a sandwich enzyme immunoassay to quantify milk proteins (casein and ß-lactoglobulin) in food containing whey, milk or milk powder such as sausages, ice cream, chocolate, bakery goods, cake and bread mix, soups, sauces, dressings and beverages (juice, wine, beer). The antibodies specifically detect caseins as well as β-lactoglobulin of cow’s milk and of sheep’s, goat’s and buffalo’s milk. The assay results are quantitative if the sample contains milk or milk powder.
If a quantitative result for casein and / or β-lactoglobulin is requested, the sample should be tested in the RIDASCREEN®FAST Casein (R4612) and / or the RIDASCREEN®FAST β-lactoglobulin (R4912).
The allergy to milk is to be distinguished from the lactose intolerance: in the case of intolerance, the symptoms are caused by a certain type of sugar (milk sugar, lactose), in the case of allergy, however, by certain proteins in the milk. Milk allergy is an allergy in the classic sense, i.e. the immune system fights a substance that is actually harmless to the body and allergic symptoms arise. Milk is consumed directly, as a drink, or as a processed product such as cream, butter, yogurt or cheese. Cow’s milk powder is widely used in baked goods, sauces and dessert.
Cow`s milk contains 3.2 % proteins which consist of 10 % β-lactoglobulin (leading protein of whey) and 80 % caseins. Casein is heat-stable, while ß-lactoglobulin is heat-sensitive. Most milk allergy sufferers are allergic to both protein fractions in milk. The most important allergen for children is β-lactoglobulin while the caseins become to be dominant later in adults. The allergen can be present as an ingredient or as a contamination in raw and cooked products. According to the regulation (EU) No. 1169/2011 milk and products thereof must be declared on food labels. Similar regulations exist e.g. in the USA, Canada, Australia and New Zealand.
Milk contains approx. 3.2 % milk protein. Thus, a sample which contains 1 mg / kg milk protein corresponds to a milk content of approx. 31 mg/kg milk.
The ELISA RIDASCREEN®FAST Milk was approved and has been certified by the AOAC Performance Tested MethodsSM Program and was assigned PTM Certification No. 101501 by the AOAC Research Institute. The in-house validation data was confirmed by an independent lab. The sandwich ELISA is applicable for the detection of milk protein (casein und β-lactoglobulin) in cookies, chocolate, ice cream, infant formula and sausages.
- AOAC-RI 101501 validated method.
- Specificity: no cross reactivities have been observed in a wide range of matrices (86).
- Validated for automates.
|Test format||Microtiter plate with 48 wells (6 strips with 8 removable wells each)|
|Sample preparation||Homogenization, extraction and centrifugation|
|Incubation time||30 min
|LOD (Detection limit)||0.57 mg / kg (ppm) milk protein (mean)
0.3 – 0.8 mg / kg (ppm) milk protein*
*depending on matrix
|LOQ (Limit of quantification)||2.5 mg / kg (ppm) milk protein|
|Cross reactivity||Sheep, goat and buffalo milk|
|Validated matrices||Sausages, ice cream, chocolate, bakery goods, cake and bread mix, soups, sauces, dressings and beverages (juice, wine, beer).|
|Available application notes||• Extraction for heavily liquid absorbing matrices using RIDA® Extractor 2 (R4613).
• Sample extraction of pine nuts, sunflower and pumpkin seed.
|Detected analyte||• Caseins
• β-lactoglobulin of cow’s milk and of sheep’s, goat’s and buffalo’s milk
|Evaluation||Microtiter plate spectrophotometer (450 nm)|