**2. Dairy products consumption: past and present**

Cow milk has been part of the human diet for 11,000 years. In the 1970s, archeologist Peter Bogucki while excavating a Stone Age site in Poland found a leaky clay pot. It was not until 2011 when molecular studies performed by Mélanie Roffet-Salque identified milk fat residues [1]. The researcher, a UK geochemistry, concluded that the container constituted evidence that prehistoric farmers used the ceramic as sieves to separate milk solids from whey. This pot is the oldest known evidence of cheese making in the world. Cheese has been a nutritional contribution in the diet of many cultures. Nowadays, 6 billion people around the world consume milk and milk products [2]. In South America alone, milk production reached 61.8 million tons in 2017 [3]. In this region, the largest producers are Brazil, Colombia, and Peru. In Brazil, fluid milk market predominates over manufacturing dairy products. While in Argentina, Mexico, Chile, and Colombia, the cheese and butter markets are more important than fluid milk [4] as it is shown in **Table 1**.

 The need to produce safe and nutritious food without environmental impact is a global challenge. Technology has contributed to improve agricultural and livestock productivity, but at the same time, the increase in production has had a negative impact, such as environmental and water pollution, deforestation, and biodiversity loss. The Food and Agriculture Organization of the United Nations estimates that by 2050, food production should increase by 70% over current production [5]. This information together with the information that currently a third of the global food is lost or waste [5] highlights the importance of rethinking food production. The term **food loss** refers to losses that occur during the supply chain between the producer and the market (e.g., during sowing, harvesting, or transporting). **Food waste** refers to the nonuse or nonfood use that can be given to raw material safe and nutritious suitable to be converted into food. The last one is the case of dairy by-products, especially in developing countries where the energy cost for technological processes such as drying or protein purification makes it economically difficult. While we are being inefficient in food production, around 870 million people do not have access to sufficient dietary energy and as a consequence suffer chronic malnutrition. Therefore, nothing should justify the voluntary loss of raw materials that could be transformed into food. The nonuse of by-products that could be transformed into food represents a waste of food and also a waste of the resources used to produce them. This inefficiency also harms environmental sustainability. Lactose is a strong pollutant due to its high oxygen demand. It is important to find alternative uses of milk by-product to avoid or at least reduce food waste.


**Table 1.** 

*Annual milk and cheese production in South America (2012–2013) [4].* 

*Introductory Chapter: Dairy By-Products - Why Should We Care? DOI: http://dx.doi.org/10.5772/intechopen.86594* 
