The past few weeks have been relatively hectic with science fair, pre-spring break tests and NLS (National Lifeguard Service). That being said, I have continued the final pieces of my literature search. Here is a very brief summary of the past three week’s research:
MS (mass spectrometry) is a protein based method and while not in common use in the food industry yet, is a new technology that allows both the identification and quantification of multiple allergens in one run. Unlike ELISA and PCR methods which have difficulty detecting some allergens and correctly quantifying them, MS identification is extremely accurate and reliable (Cowan-Lincoln, 2013). LC MS/MS (liquid chromatography tandem mass spectrometry) is the combination, much like that of ELISA and PCR, that is most effective (Sage, 2015).
In the LC MS/MS procedure, a sample from the processed food, equipment surface, or cleaning rinse is collected, the proteins extracted and digested into fragments and then run on HPLC (high pressure liquid chromatography) to be separated. A heavy isotope (13C or 15N) containing peptide of the same sequence as the known allergen(s) being tested for may be added to the sample as a standard before being run on the HPLC. Once the proteins are separated by HPLC (the heavy isotope peptide will be together with the allergen of the same sequence to confirm identification of the allergen), they are then run through MS which can separate the heavy isotope containing peptide from the allergen because of the differences in their molecular masses. Using MS, the quantity of the allergen(s) can be determined (Lutter, 2013; Jackson, 2010). One of the strengths of this method is that not only can multiple allergens be tested for but those allergens do not need to be related. For example, a single LC MS/MS run could test for the presence of and quantity of a peanut allergen, a milk allergen, an egg allergen, a soy allergen, and a gluten allergen (Lutter, 2013).
LC MS/MS has several advantages including high sensitivity and specificity, able to screen for and quantify multiple allergens at the same time, is not dependent on proper folding of the protein so is less affected by the high temperatures of food processing, has built in standards which provide reliability, and does not require antibodies (Lutter, 2013).
But there are disadvantages to this method. It is very time consuming and labour intensive, the people carrying out the analysis must be highly trained and the specialized equipment is very expensive (Jackson, 2010). The allergen must be a protein and the protein’s sequence must be known (Lutter, 2013). The major peanut allergens can be identified and quantified by LC MS/MS but it is not a method for routine analyses.
Conclusion on Commercial Peanut Allergen Detection Kits
The accurate detection of peanut allergens in processed foods is important to the food industry if it wants to be able to market its products to everyone, including people with food allergies, and comply with government regulations on labelling. There are many different methods available to the industry from the simple and inexpensive, including visual inspection and the ATP and Protein swab tests, to the more expensive and specific immunoassays, LFI and ELISA. A DNA based method, PCR, allows detection of allergens in oils which are not detected by the protein based LFI, ELISA, and protein swab tests. LC MS/MS, while very expensive and time consuming, is extremely accurate and can identify and quantitate multiple allergens in a sample. [Read more…] about Lab notebook March 6th – March 20th