# A Review of Milk Frauds and Adulterations from a Technological Perspective
## 3 Results and Discussion
### Salt
#### 3.1.4 Adulterations Associated with Increasing the Shelf Life of Milk Neutralizers  
These are added to cover the acidity and sour taste of the milk. The most popular neutralizers are sodium bicarbonate, hydrated lime, sodium hydroxide, and sodium carbonate.  
Although the addition of such alkaline substances is not allowed by law, producers tend to neutralize milk to avoid rejection in milk collection centers and factories [10; 11; 16].  
Formaldehyde  
This is an antiseptic, a disinfectant, and a good preservative. It is used to preserve milk for a long period of time (1 mL per 10 L of milk preserves it for about 10 days), especially during transport and storage to avoid refrigeration costs. It is a toxic and very dangerous substance, considered carcinogenic, and a high dose of formaldehyde can affect the liver and cause kidney damage [10; 12; 13; 14; 36].  
It has a similar role to formaldehyde and helps increase shelf life by acting as a preservative. It decreases the souring of milk when hygiene and low-temperature storage rules are not followed by stopping bacterial growth. Hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)) is largely used as a preservative in milk and dairy products around the world to activate the inherent lactoperoxidase enzyme system in areas where refrigeration is not widely available. Although, due to chemical processes within raw milk, it may contain small amounts of hydrogen peroxide (1-2 mg/L), the concentration necessary to inactivate pathogens is 10 times higher. In addition, the presence of H\({}_{2}\)O\({}_{2}\) in high concentrations can lead to modifications in the milk's chemical composition. At the same time, the addition of hydrogen peroxide for the purpose of preserving milk is prohibited for the following reasons: it masks to some extent negligence in the observance of hygienic conditions; it has a germicidal action that is not selective, acting more strongly on lactic bacteria than on spoilage microflora; used in larger quantities to ensure preservation for 1-2 days, it can impart undesirable sensory properties to milk (bitter, irritating taste); added even in small quantities, hydrogen peroxide, through the active oxygen released, causes incipient oxidation of milk fat. The US Food and Drug Administration (FDA) only allows hydrogen peroxide in milk that is used for cheese production [11; 13; 37].  
Acids  
These are added to milk as preservatives. The most common are salicylic acid and benzoic acid, which are responsible for increasing shelf life. Salicylic acid added to milk at a rate of 0.04-0.05% preserves the product for several days. Salicylic acid and its salts are prohibited for use in the preservation of milk because of their harmful effects on the body and other negative implications. Benzoic acid is widely used in foodstuffs as a preservative. Although benzoic acid is generally recognized as safe (GRAS) under the food regulations, benzoic acid is not a permitted preservative in milk and milk beverages in the EU and China. WHO has assessed and established an acceptable daily intake (ADI) for benzoic acid of 0-5 mg/kg body weight [10; 13; 15; 38; 39; 40].