# A Review of Milk Frauds and Adulterations from a Technological Perspective
## 3 Results and Discussion
### The Most Common Milk Adultrations
#### 3.1.1 Adulteration That Generally Aimed at Increasing the Volume of Milk  
This type of adulteration can be performed by adding water or skimmed milk to whole milk, as well as by double forging by both adding water and reducing the fat content of the milk [7; 16]. Addition of Liquid Whey (a By-Product of Cheese Making)  
This is a well-known practice to increase the volume of milk, and it is noticed especially in cases where a large amount of cottage cheese is produced, but it has serious economic effects, by obtaining products derived from milk with low nutritional value [21]. The advantage of whey addition in moderate proportion is that it does not significantly change the milk's lactose and protein content without producing a series of sensory changes noticeable to consumers. [22]. In addition, the whey added to the milk does not change the overall milk density but reduces the solids and fat content, which decrease in proportion to the whey added. In this particular case, it is the fat that reflects the adulteration. Moreover, the addition of whey cheese to milk is very difficult to detect by formal analytical procedures, making it necessary to implement new experimental procedures/  
Figure 1: The most common forms of adulteration of raw milk. tests [11; 12; 20; 23; 24]. Casein macropeptide (CMP) content analysis is a standard method for detecting and quantifying whey that has been purposefully added to milk. This K-casein fragment is hydrophilic and should not be present in milk, but it is still soluble in whey [22]. Addition of Reconstituted Milk or Synthetic Milk  
Synthetic milk is a remarkable imitation of milk, which contains vegetable oil, urea, and emulsifiers. It is well-known for its fat, nitrogen, glucose, and foam content, as well as a specific gravity similar to that of natural milk. When the synthetic milk is mixed with normal milk in different proportions, it becomes identical to it, including flavor. It is reported that synthetic milk is used to alter milk by 5-10% [3; 13]. In addition, Table 1 lists the physical and chemical characteristics of natural and synthetic milk that differ most frequently. Unlike synthetic milk, natural milk does not produce foam when rubbed on the palm. Both milks' pHs differ significantly from one another. Natural milk has a pH range of 6.6 to 6.7, but synthetic milk has a pH range of 10 to 11. Synthetic milk has a very alkaline character. Natural milk doesn't change color when heated, while synthetic milk turns yellow when it's boiled. While artificial milk gradually turns pale yellow over time, natural milk stays white when stored. Yet, the percentages of non-fat solids and fats are the same in each [25]. Partial Skimming and Addition of Skimmed Milk  
This practice is most often used when milk with a high fat content, milked in the evening, is skimmed and added on top of whole milk. Milk fat is one of the most valuable components and therefore can be subject to fraud; hence, removing a quantity of fat leads to changes in the characteristics of the milk: the density increases and the fat content decreases in proportion to the degree of skimming. The dry matter in the milk may increase, or its value may remain unchanged [11; 26]. Diluting Milk with Water  
This is the most common, simplest, and oldest method of adulteration, based on the percentage reduction of all milk components and the addition of chemicals to bring the density and color to normal parameters. The milk will increase considerably in volume; hence, the producers will earn a significant profit, but the nutritional value and other