risk of cross-reactivity, while mare’s and donkey’s milks, used in popular practice for allergic children, are valid alternative protein sources when appropriately evaluated from the hygienic point of view 19. The discussion on the use of soy-based infant formula is difficult, since scientific societies have different recommendations. There is a broad consensus on the following statements: the incidence of soy allergy in soy formula-fed infants is comparable to that of CMPA in cows’ milk formula-fed babies 20. Cross reactivity to soy has been reported in 10% to 35% of infants with CMPA, regardless whether they were positive or negative for specific IgE for CMP. In particular, infants with multiple food allergies and eosinophilic enterocolitis also react to soy protein; therefore, different specialist groups have different standpoints on the use of Soy formula for CMPA, but is generally not recommended before the age of 6 months 20.
The donkey (Equus asinus) is a member of the horse family, it worked together with humans for centuries, the most common role was for transport. It still remains an important work animal in the poorer regions. Compared with ruminant’s milk, donkey milk has been studied less in the past, but in the last years research interest and capital investment in donkey milk have increased. The protein composition is significantly different from cow’s milk (Table 1): the total content is lower (1.5–1.8 g/100 g) and quite similar to that of human and mare milk; this condition avoids an excessive renal load of solute 21. The main difference is the proportion of whey proteins: they are 35%–50% of the nitrogen fraction while they represent only 20% in cow’s milk 22. Comparing donkey’s and mares milk, the casein to whey protein ratio in mares milk is 0.2:1 immediately post-partum, and changes to 1.2:1 during the first week of lactation 23