1. IntroductionThe economic adulter

1. Introduction
The economic adulteration of milk and infant formula products
in China with melamine and cyanuric acid resulted in the sickening and deaths of infants fed with adulterated milk powder and
received wide spread global attention during the melamine scandal in 2007 [1]. The 2007 melamine incident was preceded by pet
foods adulteration with melamine and cyanuric acid which resulted
in renal failure and deaths of cats and dogs [2]. The intentional
adulteration of food ingredients with nitrogen-rich compounds has
created lasting ramifications for food safety, regulations, and global
commerce [3].
Economic adulteration of nutritional ingredients involves mixing with nitrogen rich compounds for economic gains, which in
turn causes an interference with the widely used Kjeldahl protein
assay [4,5]. The Kjeldahl method measures total nitrogen as an indirect measure of protein content [6]. The lack of specificity of the
∗
Corresponding author. Tel.: +1 614 6246179; fax: +1 614 7276179.
E-mail address: todime.reddy@abbott.com (T.M. Reddy).
Kjeldahl method makes it susceptible to tampering by the addition
of nitrogen rich compounds to inflate the apparent protein content.
Today a heightened awareness of the melamine issue, the
availability of reliable analytical test methods and increased regulations, collectively decrease the risk of repeat occurrence of
melamine–cyanuric acid incidents [7–9]. However motivation of
economic adulteration still remains despite the above advances
and the potential use of melamine related analogs for adulteration
provides opportunity. Hence the continuous development of new
analytical screening methodologies which are capable of detecting
the presence of externally introduced nitrogen-rich compounds in
food ingredients is needed to ensure the safety of ingredients and
finished products.
Milk derived ingredients are major components of infant and
adult nutritional products. Milk is traded globally mainly in the
form of powdered ingredients because of its ease of transport
[10]. The breadth and complexity of growing global trade involves
supply chains which span various continents and milk derived
ingredients being sourced from different regions of the world.
Globally sourced ingredients are used to manufacture nutritional
products which are in turn sold around the world. Hence rapid
determination of residues of nitrogen rich melamine analogs in