Technological failures caused by cephalexin in set-type sheep’s milk yogurt

Abstract

Given their broad spectrum, cephalosporins are used for combating mastitis in dairy species. Many cephalosporins, such as cephalexin, have not been authorized for use in lactating sheep and because veterinary drugs for use in small species are lacking, the regulations of several countries allow extra-label use. Incorrect use of extra-label tools may cause residues in milk, and could negatively affect public health by provoking technological failures in the dairy fermenting processes. The effects of cephalexin, at concentrations close to its European Maximal Residue Limit (MRL), have been studied in set-type yogurts made from sheep’s milk. Milk was fortified at different cephalexin concentrations and stored yogurts were evaluated in acidification, textural parameters and microbial evolution terms. The results showed that cephalexin concentrations equal to or below its MRL could mainly inhibit normal Streptococcus thermophilus growth and provoke some alterations to acidity parameters, which were more marked in the L(+)-lactic acid isomer.