# 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)  
To effectively protect consumers and promote trade, an acceptable level of food quality and safety must be guaranteed. Modern biotechnology offers a range of rapid, sensitive, and accurate methods for the detection and analysis of adulterants in food products. However, recent incidents of adulterated milk contamination have shown that standards in milk quality control are insufficient in identifying poor quality milk. Therefore, different methods have been studied and applied precisely to combat these problems. In addition, such detection methods require large investments. Another important aspect is that the type of quantitative detection technique depends on the nature of the adulterants in milk. Although there are fairly well-known techniques based on portable equipment, those  
Figure 2: Color-based reactions for the determination of adulterants in milk (adapted from [PERSON] et al., 2015) \(QAC\) = Quaternary Ammonium Compounds [47]. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{1}{c}{**Adulterants**} & \multicolumn{1}{c}{**Details of Qualitative Tests**} \\ \cline{2-3} \multicolumn{1}{c}{} & **Test** \\ \hline Detergent & Methylene blue \\ Urea & p-dimethylaminobenzaldehyde test (DMAB) \\ Ammonium salts & Nessler \\ Sucrose & Selivanoff \\ Glucose & Barfooled \\ Maltodextrin & Iodine \\ Starch & Iodine \\ Salt & Silver nitrate test \\ Nitrate & Diphenylamine \\ Sulphate & Barium chloride \\ Hydrogen peroxide & Iodometric test \\ Formaldehyde & Hehner \\ Neutralizers & Rosolic acid \\ \hline \hline \end{tabular}
\end{table} 
Table 3: List of qualitative tests for finding common milk adulterants that have been reported (adapted from [PERSON] et al. [35]). designed and developed recently require experimental set-up and much more expensive equipment, as well as a number of operational procedures [16]. About ten years ago, studies of milk and milk products could only be conducted in laboratories using chemical or physico-chemical techniques. Since they are direct procedures, they are seen to be the most trustworthy; nonetheless, such an analysis is time-consuming (the analysis might take up to 15 h), a process that calls for expertise and specialized knowledge on the part of the personnel, as well as high-purity chemicals. This causes a rise in the cost of the assessment of raw materials, as well as a reduction in the accuracy of the results due to imperfect reagents, the presence of human factor in the laboratory, and the subjective evaluation of the results. Although in principle they are simple methods, systematic errors in the analysis, such as a significant difference of up to 0.3% fat, often arise when the indicators of the used device, even if these are calibrated according to the manufacturer's data, differ from the indicators obtained by reference methods, such as the Gerber method for fat determination. This leads to discrepancies between the milk analyzer readings and the results obtained from the chemical analysis data precisely because the Gerber method was not correctly carried out. In addition, thanks to new technologies, quality analysis is carried out much faster and depends less on the qualifications of employees. Therefore, priority is currently given to indirect methods of data collection. The analytical methods by which milk authenticity can be demonstrated are presented in Figure 3[12; 48; 49; 13]. Techniques for Identifying Adulterants in Nitrogen Content  
As it is already mentioned, this common adulteration is difficult to detect because the Kjeldahl and Dumas methods used to quantify the total protein content of milk cannot distinguish with accuracy the nature of the non-protein nitrogen. For the detection of these nitrogen chemicals in milk, many analytical techniques have been created since 2010.