# A Review of Milk Frauds and Adulterations from a Technological Perspective
## 1 Introduction  
Milk is undoubtedly a ubiquitous food in the human diet. This is the first food of mammals and, as such, provides all the energy and nutrients needed for proper growth and development. The nutritional richness of milk is indisputable; it is a good source of protein with high biological value and polyvalent roles in immune function as well as nutrient transport and absorption, and of course, it contains essential vitamins and minerals [1]. According to annex VII, part III of the REGULATION (EU) No 1308/2013, milk and milk products are defined as the normal mammary secretion of milling animals, without any addition or extraction thereof, intended for consumption as liquid milk or for further processing [2, 3]. At the same time, fraud from a legal point of view is defined by Directive (EU) No 2017/1371 from Regulation (EC) No 178/2002 of the EU food law, as the general framework from the point of view of the protection of consumers' interests with regards to the prevention of fraudulent or deceptive practices, the adulteration of food, and any other practices that may mislead the consumer [4, 5]. Adulteration of milk and dairy products has become a worldwide concern, however the history of milk counterfeiting is very old. In the old German Empire, milk was diluted, and then its consistency was restored by adding sugar, flour, or calcium carbonate. In addition, this process dates back to 1850, when 8000 babies died in New York from milk produced by the Swill factories because the milk came from animals fed on by-products from distilleries and was then adulterated by dilution with water, bleached by adding plaster, and thickened with starch. Until the early 1900s, the milk was often adulterated with foreign substances obtained from sick cows or mishandled during milking and storage. As a result, milk was often the host of tuberculosis, cholera, typhoid fever, and other life-threatening diseases. It was not until the end of the 19 th century, when scientists began to fully understand theories about microorganisms, that they realized that diseases are transferred through milk and that they could intervene to eliminate this risk. Finally,the last resounding case of milk adulteration worldwide is represented by the melamine contamination of infant products in China in 2008 [6; 7; 8; 9; 10; 11; 12; 13]. Unfortunately, milk and dairy products are among the most counterfeited foods worldwide. The reasons behind this fraud are mainly the perishable nature of milk, the shortage of supply and demand to meet urban demand, and the lack of adequate detection methods [14]. According to studies, milk is the second most susceptible to counterfeiting, after olive oil. Thus, it is adulterated with harmful substances that increase its quantity but considerably reduce its quality [11; 12; 15]. In addition to its microbiological quality and safety, the quality of milk is usually defined on the basis of its nutrient levels (mainly protein and fat). These parameters were used to calculate the payment to the supplier. In general, the parameters usually used to assess milk quality are fat, protein, solids (non-fat), and freezing point. The adulterants added to milk improve the value of these parameters, thus increasing milk quality in a dishonest manner [11; 16]. As it is equally important to inform consumers about common adulterants and their possible effects on health, appropriate consumer awareness can be considered a solution to warn against dishonest practices and counterfeiting in the food industry [11; 12; 13; 15]. Although consumers have a right to believe that the milk they purchase will be pure and unadulterated, this is regrettably not always the case. Adulteration is normally carried out either for financial gain or because of a lack of proper hygiene during processing, storage, transport, and marketing. Eventually, it reaches the stage where the consumer is either deceived or becomes a victim of disease. Milk is produced throughout the year.