Almost all of the data in literature related to the water footprint of food products which are not currently available or used for communication were published by the Water Footprint Network (WFN) or by various authors in scientific journals when referring to the calculation methodology developed by this network. This was in fact the most widely used protocol at international level until the publication of the ISO 14046 standard.

Since high water footprint values are one of the main issues concerning meat and cured meats production, this indicator should be analysed in depth as well as the precautions to be taken in the trial stage. As regards to beef, available data report a total water footprint value of approximately 15,400 litres/ kg, of which 94% is green water, 4% is blue water and only 2% is grey. This value refers to a kilogram of meat produced at global level by averaging the values of the various rearing systems (pasture, industrial, mixed) in different regions of the world.

Therefore, the figure is obtained by comparing the various types of production systems and extremely different climatic regions between one another: which ranges between over 26,000 litres per kg from cattle grazing in India, to the 3,000 litres used by Argentine or US industrial systems.

As well as this great variability in the overall value there is also a high variability in the composition: 99% of the water required for grazing livestock is green, yet this value may drop to under 90% in the case of an industrial system. For Italy the data indicate an average value of 11,500 litres of water per kg of meat produced, of which 87% green, 5% blue and 8% grey.

By applying the methodological considerations to the newly presented data, one can comprehend how making hasty use of the indicators can lead to misunderstandings. One example is that the overall water footprint (the sum of the green, blue and grey waters) for industrial systems is much lower than for mixed and extensive systems (cattle reared mainly by grazing).

Industrial systems are generally more efficient: in fact, using concentrates leads to a reduction in the feed conversion index, which correlates the amount of food consumed by the cattle with the increase in meat. However, a lower overall water footprint corresponds to larger quantities of blue and grey water, due to the need for feed whose cultivation requires blue water for irrigation and grey water to eliminate the contamination caused by using fertilizers.