title: Detection of target staphylococcal enterotoxin B antigen in orange juice and popular carbonated beverages using antibody-dependent antigen-capture assays.
abstract: There is a critical need for qualitative and quantitative methodologies that provide the rapid and accurate detection of food contaminants in complex food matrices. However, the sensitivity of the assay can be affected when antigen-capture is applied to certain foods or beverages that are extremely acidic. This study was undertaken to assess the effects of orange juice and popular carbonated soft drink upon the fidelity of antibody-based antigen-capture assays and to develop simple approaches that could rescue assay performance without the introduction of additional or extensive extraction procedures. We examined the effects of orange juice and a variety of popular carbonated soft drink beverages upon a quantitative Interleukin-2 (IL-2) enzyme-linked immunosorbent assay (ELISA) assay system and a lateral flow device (LFD) adapted for the detection of staphylococcal enterotoxin B (SEB) in foods. Alterations in the performance and sensitivity of the assay were directly attributable to the food matrix, and alterations in pH were especially critical. The results demonstrate that approaches such as an alteration of pH and the use of milk as a blocking agent, either singly or in combination, will partially rescue ELISA performance. The same approaches permit lateral flow to efficiently detect antigen. Practical Application: The authors present ways to rescue an ELISA assay compromised by acidity in beverages and show that either the alteration of pH, or the use of milk as a blocking agent are not always capable of restoring the assay to its intended efficiency. However, the same methods, when employed with lateral flow technology, are rapid and extremely successful.
authors.affiliation: U.S. Food and Drug Administration, CFSAN 8301 Muirkirk Rd., Laurel, MD 20708, USA. maryann.principato@fda.hhs.gov
authors.forename: MaryAnn
authors.initials: M
authors.lastname: Principato
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Njoroge
authors.forename: Andrei
authors.initials: A
authors.lastname: Perlloni
authors.forename: Michael
authors.initials: M
authors.lastname: O' Donnell
authors.forename: Thomas
authors.initials: T
authors.lastname: Boyle
authors.forename: Robert L
authors.initials: RL
authors.lastname: Jones
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis; D001628:Beverages / Q000032:analysis*; D002253:Carbonated Beverages / Q000032:analysis*; D032084:Citrus sinensis / Q000737:chemistry*; D004768:Enterotoxins / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005506:Food Contamination; D005513:Food Inspection / Q000379:methods*; D005638:Fruit / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000737:chemistry; D007376:Interleukin-2 / Q000737:chemistry; D008894:Milk Proteins / Q000737:chemistry; D011934:Reagent Strips; D015203:Reproducibility of Results; D013211:Staphylococcus aureus / Q000276:immunology; D018089:Superantigens
chemical_list: D000942:Antigens, Bacterial; D004768:Enterotoxins; D007202:Indicators and Reagents; D007376:Interleukin-2; D008894:Milk Proteins; D011934:Reagent Strips; D018089:Superantigens; C031818:enterotoxin B, staphylococcal