Rapid turbidimetric detection of milk powder adulteration with plant proteins.
Development of assays to screen milk for economically motivated adulteration with foreign proteins has been stalled since 2008 due to strong international reactions to the melamine poisoning incident in China and the surveillance emphasis placed on low molecular weight nitrogen-rich adulterants. New screening assays are still needed to detect high molecular weight foreign protein adulterants and characterize this understudied potential risk. A rapid turbidimetric method was developed to screen milk powder for adulteration with insoluble plant proteins. Milk powder samples spiked with 0.03-3% by weight of soy, pea, rice, and wheat protein isolates were extracted in 96-well plates, and resuspended pellet solution absorbance was measured. Limits of detection ranged from 100 to 200 μg, or 0.1-0.2% of the sample weight, and adulterant pellets were visually apparent even at ∼0.1%. Extraction recoveries ranged from 25 to 100%. Assay sensitivity and simplicity indicate that it would be ideally suitable to rapidly screen milk samples in resource poor environments where adulteration with plant protein is suspected.
Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration , 5100 Paint Branch Parkway, HFS-707, Room BE-006, College Park, Maryland 20740, United States.
Peter F
PF
Scholl
Samantha M
SM
Farris
Magdi M
MM
Mossoba
D000818:Animals; D002417:Cattle; D005506:Food Contamination / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D012275:Oryza / Q000737:chemistry; D018532:Pisum sativum / Q000737:chemistry; D010940:Plant Proteins / Q000032:analysis*; D011208:Powders / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry; D014908:Triticum / Q000737:chemistry
D010940:Plant Proteins; D011208:Powders