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.Keywords: yogurt; sheep milk; cephalosporin antibiotics; antimicrobial agents; lactic acid; acidity; viscosity; texture; microorganisms Dado su amplio espectro, las cefalosporinas se utilizan con frecuencia para tratar mastitis en especies lecheras. Muchas cefalosporinas, como la cefalexina, no están autorizadas para su uso en ovejas en lactación, pero debido a la escasez de medicamentos autorizados para su uso en especies menores como ésta, la legislación de muchos países permite su uso "extra label" (fuera de etiquetado). La utilización incorrecta de la herramienta "extra-label" podría causar residuos en leche, afectar negativamente a la salud pública y provocar fachos tecnológicos en los procesos fermentativos lácteos. En este trabajo se ha estudiado el efecto que concentraciones cercanas al Límite Máximo de Residuos europeo (LMR) podría tener sobre yogures elaborados con leche de oveja. Para ello, se han adicionado diferentes concentraciones de cefalexina a leche y los yogures elaborados con ésta se han evaluado a lo largo de su almacenamiento sus parámetros de acidificación, textura y evolución microbiana. Los resultados demostraron que concentraciones de cefalexina iguales o inferiores al LMR inhibieron el normal desarrollo de Streptococcus thermophilus, y causaron algunas alteraciones en los parámetros de acidez, principalmente en sobre el isómero L(+) del ácido láctico.

Why knowledge is the best way to reduce the risks associated with raw milk and raw milk products

“…If milk and its products are obtained from the clandestine market, then the hazards and risks are those mentioned above. These issues can result in low quality products, low yields, microbiological fermentation failures due to possible antibiotic residues and taste defects (Fleischer et al ., 2001; Novés et al ., 2015). These taste defects may be of microbiological origin, caused by bacteria that produce proteolytic and lipolytic enzymes, and/or physical factors such as oxidative rancidity caused by exposure to light (Cadwallader and Singh, 2009).…”

Control and prevention of antibiotic residues and contaminants in sheep and goat’s milk

“…The presence of such substances also affects the dairy industry as bacteria sensitive to antibiotics most widely used in many fermentation processes, result in spoiling the organoleptic properties of the final products, and coagulation or maturation of dairy products may fail. Studies into sheep milk yoghurt have observed that the levels of betalactam residues that come close to or below the MRL could delay coagulation by more than 40 minutes, cause variations in final compositions (Berruga et al, 2007a(Berruga et al, , 2008bNovés et al, 2015), and could delay the pH in pressed cheeses from lowering by between 5-300 minutes (Berruga et al, 2007b). It is noteworthy that most heat treatments employed in the dairy industry have no strong impact on residues since they do, in general, not deactivate after heat treatment (Roca et al, 2010, Zorraquino et al, 2008).…”

Conductive imprinted polymers for the direct electrochemical detection of β-lactam antibiotics: The case of cefquinome

“…β-lactam residues in milk and other animal tissues are a cause of concern for authorities and consumers: they induce allergic reactions in hypersensitive individuals [32], interfere with the fermentation processes used by dairy industries [33] and contribute to the spreading of antimicrobial resistance [34]. To prevent such consequences, the European Union has established specific threshold values for each drug in food commodities, namely the Maximum Residues Limits (MRLs) [35].…”