# A Review of Milk Frauds and Adulterations from a Technological Perspective
## 3 Results and Discussion
### Methods for Detecting Adulterants in Milk
#### 3.2.3. Instrumental Methods (Quantitative)
The approach may also be able to define the type of fat or oil supplied while giving an estimate of the adulteration level because comprehensive TAG profiles are available [71]. Techniques for Identifying Additional Adulterants Added to Increase the Shelf Life of Milk  
It is absolutely necessary to identify the adulterants added in order to extend the shelf life of milk, precisely because they have harmful effects on human health. Many chemicals, including formaldehyde, salicylic acid, hydrogen peroxide, hypochlorite, and potassium dichromate, are included in this group of adulterants and are difficult to identify due to their ability to decompose. To identify these adulterants, analytical approaches including fluorimetry, portable spectroscopy using chemometric instruments, spectrophotometry, amperometry, and HPLC have been reported in the literature, but these require expensive equipment, and the development of cheap and rapid detection instruments is needed in the future. In recent years, a series of techniques have been proposed that perform for this purpose, and the most relevant examples are presented in Tables 5 and 6[48; 72]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Adulterant** & **Detection Technique** & **Advantage** & **Disadvantage** & **Reference** \\ \hline \multirow{4}{*}{Hydrogen peroxide} & \multirow{4}{*}{Optical Biosensor} & Quick, economical, and environmentally friendly methods with good repeatability, concentrations as low as 0.001\% \(\gamma/v\) can be measured. & The systematic optimization of the membrane used. The need for reagents. & [73] \\  & & Simple, cheap, disposable, accessible, and flexible. & All reagents used must be of analytical quality. The need for the subsequent use of chemometric methods. & [72] \\  & & Minimal amounts of reagent and sample are needed. & & \\ \hline \multirow{4}{*}{Hydrogen peroxide} & HPLC with a diode-array based on the oxidation of triphenylphosphine into triphenylphosphine oxide & Optimized method validated with acceptable linearity. & A small possibility exists for milk components to interact & [37] \\  & & Suitable for use in most laboratories (routine technique). & & \\ \hline \multirow{4}{*}{Hydrogen peroxide} & Non-enzymatic sensor of Cu\({}_{\text{x}}\) O/Ag nanoparticles on exfoliated graphene & High sensitivity over an extremely wide range of concentrations. Exceptional selectivity and long-term stability. & A lot of materials and chemicals are needed for the careful construction of this sensor. & [74] \\ \cline{1-1}  & & & \\ \cline{1-1}  & & & \\ \cline{1-1}  & & & \\ \cline{1-1} \cline{3-3} \cline{5-5} \cl  
Techniques for Identifying Adulteration with Water and Other Substances  
According to data from the literature, the detection of added water in milk is not an easy task at all. Utilizing a lactometer or another traditional technique, the specific gravity is measured. These strategies fall short, though, if the weight after the adulteration is maintained at the same level [81; 82; 83]. Over time, many methods have been used to determine this type of adulteration, such as high performance liquid chromatography (HPLC), capillary electrophoresis, Fourier transform infrared spectroscopy (FTIR), and methods for determining the cryoscopic point. Even if these techniques work, they are expensive, time-consuming, and require high-purity chemicals and expensive equipment, which leads to higher prices and slower outcomes. [81]. Other methods studied were spectroscopic methods based on electrical impedance, which, in addition to adding water, are able to detect even fomaldehyde, hydrogen peroxide, and sodium hydroxide. The electrical analysis of adulterated milk samples in the study of [PERSON] and his collaborators helped to determine the quantity of adulterants, allowing the development of real-time monitoring systems for the detection of these frauds [82]. In a different investigation by [PERSON] et al., the electrical impedance of milk was measured using a VDP bioimpedance sensor to ascertain its electrical characteristics.