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

[EN] The use of veterinary drugs to treat mastitis and other pathologies in dairy sheep and goats is a usualpractice in current production systems. The risk of antibiotic residues in milk on farms is high if goodfarming practices are not applied, in this sense control measures must be implemented to prevent drugresidues from entering the food chain. Moreover there are other compounds that may contaminate milkvia the environment, water or animal feed, such as mycotoxins that are one of the most harmful contam-inants given their negative effects on consumer health. This work presents the problems that arise whenresidues and contaminants are present in sheep and goat s milk. It also addresses the causes and theconsequences of their presence, and the main measures of prevention and control required to guaranteemilk that is safe for consumers and of high quality for the dairy industry.Berruga Fernandez, MI.; Molina Casanova, AM.; Althaus, RL.; Molina Pons, MP. (2016). Control and prevention of antibiotic residues and contaminants in sheep and goat s milk. Small Ruminant Research. 142:38-43. https://doi.org/10.1016/j.smallrumres.2016.02.023S384314

Microbial System for Identification of Antibiotic Residues in Milk

[EN] The aim of this study was to evaluate the ResScreen (R) microbiological system for the identification of antibiotic residues in milk. This microbiological system consists of two methods, the BT (betalactams and tetracyclines) and BS (betalactams and sulfamides) bioassays, containing spores of G. stearothermophilus subsp. calidolactis, culture media and indicators (acid-base and redox). The detection limits of 29 antimicrobial agents were calculated using a logistic regression model. Both methods detect residues of penicillin-G, ampicillin, amoxicillin, cloxacillin, oxacillin, cephalexin, cefoperazone and ceftiofur (R) at levels close to their Maximum Residue Limits (MRL). The BT bioassay also presents good sensitivity to tetracycline and oxytetracycline residues, whereas the BS bioassay detects sulfadiazine, sulfamethoxazole and sulfathiazole residues in milk. The simultaneous use of both bioassays identifies betalactam, tetracycline and sulfamide residues in milk. Neomycin, tylosin and lincomycin residues can also be detected, but these molecules arc positive with the BT and BS bioassays, e.g., betalactams, given the microorganisms' sensitivity to these molecules.This research work has been carried out as part of the CAI+D'09/11 Project (No. 033-173 Res.C.D. No. 100/09) and supported by financial assistance from the Universidad Nacional del Litoral (Santa Fe, Republica Argentina).Nagel, OG.; Molina Pons, MP.; Althaus, RL. (2011). Microbial System for Identification of Antibiotic Residues in Milk. Journal of Food and Drug Analysis. 19(3):369-375. http://hdl.handle.net/10251/80981S36937519

Academic Contest and Social Networking to Promote Technology and Information Literacy among University Students

AbstractSpanish universities have recently adapted their studies to the requirements of the European Higher Education Area (EHEA). This process has involved the consideration of the development of computer and informational skills as an academic objective. In order to develop these skills, among other activities, an informative video has been disseminated. The design of the communication campaign, developed through viral marketing and social networks has been the result of and empirical research carried out by students of the University of Valencia. This paper describes the research objectives, questions, techniques and main findings

Aflatoxin M1 in the intermediate dairy products from Manchego cheese production: distribution and stability

[EN] Aflatoxin M1 (AFM1 ) distribution in curd, whey, Manchego cheese, the traditional Spanish whey cheese Requesón and Requesón whey, and its stability during two different cold treatments, have been studied. Raw ewe¿s milk was artificially contaminated with AFM1 in a final concentration of 50 and 100 ng kg-1, and was used to produce Manchego cheese. AFM1 determinations were carried out by HPLC with fluorimetric detection after immunoaffinity clean-up. The mean AFM1 concentrations in the produced curd and Manchego cheese were approximately 2- and 3-fold higher than the initial milk they were made from, and the levels of this toxin remaining in whey were 42.3 % and 51.3 % of the initial concentrations. In the Requesón samples, the mean AFM1 values were 1.7 times higher than those in the corresponding whey, while 33.7 % and 44.4 % of the AFM1 concentration detected in milk also appeared in the Requesón whey. Short refrigeration and freezing periods did not affect the toxin levels in either curd or Requesón samples. When ewe¿s milk destined for Manchego cheese-making is AFM1 -contaminated at the EU limit level (50 ng kg-1) or double, a concentration of this toxin will appear in the manufactured products, but values will be considerably below the toxic doses (Tolerable Daily Intake = 2 ng kg-1 body weight per day), which poses a human health problem.Rubio, R.; Moya Salvador, VJ.; Berruga Fernandez, MI.; Molina Pons, MP.; Molina Casanova, A. (2011). Aflatoxin M1 in the intermediate dairy products from Manchego cheese production: distribution and stability. Mljekarstvo. 61(4):283-290. http://hdl.handle.net/10251/90949S28329061

Microbiological method using Bacillus megaterium with fusidic acid for detection of macrolides in milk

[EN] The microbiological method to attain a sensitive detection of macrolides using Bacillus megaterium in agar medium with fusidic acid was designed. To this aim, Mueller-Hinton medium fortified with glucose at pH 8.0, a combination of redox indicators (brilliant black and toluidine blue) and different concentrations of fusidic acid were tested. The addition of fusidic acid in the culture medium improves the sensitivity of this bacteria test and decreases the detection limits of bioassay. The addition of 200 μg/l of fusidic acid detects 35 μg/l of erythromycin, 58 μg/l of tylosin, and 57 μg/l of tilmicosin in milk. This microbiological bioassay could be used as an alternative method of commercial screening test for detecting macrolides in milk, in order to maintain food safety.Partly supported by the Universidad Nacional del Litoral, Santa Fe, Argentina, CAI+D-11 Projects PI 501 201101 00575 LI, H.C.D. Resol 205/13, and Agencia Nacional de Promocion Cientifica y Tecnologica, PICT 2011-368 Res. No. 140/12.Tumini, M.; Nagel, OG.; Molina Pons, MP.; Althaus, RL. (2016). Microbiological method using Bacillus megaterium with fusidic acid for detection of macrolides in milk. Czech Journal of Food Sciences. 34(1):9-15. https://doi.org/10.17221/307/2015-CJFSS91534

Detection of antibiotics in goats' milk: Comparison of different commercial microbial inhibitor tests developed for the testing of cows' milk

[EN] Nine microbial inhibitor tests validated for cows' milk (BR-AS Special, CMT-Copan Milk Test, Delvotest SP-NT, Delvotest T, Brilliant Black Reduction Test MRL, Charm Blue Yellow II, Charm CowSide II, Eclipse 100, Eclipse 3G) were applied to milk samples from 200 different individual goats. Interpretation of the results was based on visual and instrumental reading. Samples initially testing positive were retested and also tested after a milk pre-treatment (heat treatment, fat removal or fat removal followed by heat treatment). With instrumental reading, most microbial tests commonly used for bovine milk were suitable for goats' milk (specificity 95%), except for BR-AS Special, Charm Blue Yellow II and Delvotest SP-NT. However, visual reading of the results decreased the specificity, with 95% specificity only for CMT-Copan Milk Test, Eclipse 3G and Delvotest T. Fat removal followed by heat treatment proved the most appropriate milk treatment to reduce false positive results for almost all tests.This work forms part of the grant EEBB-I-13-06255 financed by the Ministry of Science and Innovation (Madrid, Spain). The authors are grateful to Analytik in MilchProduktions-und Vertriebs-GmbH, Charm Sciences Inc., DSM Food Specialties, ZEULAB S.L. for their technological support. The authors thank MCC-Vlaanderen and Comite du Lait for the assistance with milk quality and composition analysis and appreciate the cooperation of the commercial dairy goat farms: J. VanWaes (Zaffelare, BE), 't Eikenhof (Lokeren, BE) and 't Leenhof (Zele, BE).Romero Rueda, T.; Van Weyenberg, S.; Molina Pons, MP.; Reybroeck, W. (2016). Detection of antibiotics in goats' milk: Comparison of different commercial microbial inhibitor tests developed for the testing of cows' milk. International Dairy Journal. 62:39-42. https://doi.org/10.1016/j.idairyj.2016.07.004S39426

Effect of subclinical mastitis on the yield and cheese-making properties of ewe's milk

[EN] This review covers an update of scientific knowledge about productive and technological consequences of subclinical mastitis in sheep milk. The literature reports individual milk yield losses of 2.6-43.1 %, being modulated by several factors as infection severity, production level, causal agents, and unilateral or bilateral IMI (1 or 2 infected glands, respectively). A compensatory increase of milk production from the uninfected gland when only one half was infected has been quantified in 6.6 %, compared with healthy halves of control sheep. This compensatory adaptation highlights the risk of underestimating subclinical mastitis in sheep. The mammary gland response is quick and milk yield losses in absolute terms remained constant within the following weeks, both when infection appear during lactation and when it is present from lambing. With respect to the changes on main components in milk due to subclinical mastitis it has been clearly established a decrease in the concentration of lactose and an increase of that of whey proteins. The role played by lactose as an osmotic regulator results in a more accentuated decrease of its concentration in milk. This is why lactose is considered at present as a reliable potential indicator of subclinical mastitis. Whey proteins increase as a result of the increase of the blood-milk barrier permeability and the increased proteolysis of caseins. However, the content in milk of fat and casein are modified depending on the magnitude of milk yield reduction, being affected by a concentration or dilution effect. In any case, the ratio casein to protein (parameter independent of the milk volume) decreases as a result of infection. The impairment of physical and chemical characteristics due to decreased udder health status is the responsible of the negative effect of increased SCC on the coagulation properties of milk, the curd yield and the quality of cheese. Low ratio of casein to protein in high bulk tank SCC milk enhances the extension of the rennet coagulation time (RCT) and curd firming time (k20) because there are more serum proteins and the stability of casein micelles are reduced as a result of hydrolysis. Those changes in turn led to poor syneresis, lower cheese yield, increased moisture content and lower fat and protein content in cheese. Finally, there is a favourable relationship between lactose and milk technological properties because the decrease of this component in case of mastitis is associated with an increase of milk pH. Thus, the three parameters, SCC, pH, and lactose affect, contemporarily and independently, milk quality and coagulation properties, and this is why have been highlighted as potential indicators traits for improving cheese-making ability of sheep milk.This review is based on knowledge gained during work financially supported by means of a research fellowship from the regional government of Valencia ("Generalitat Valenciana").Martí-De Olives, A.; Peris Ribera, CJ.; Molina Pons, MP. (2020). Effect of subclinical mastitis on the yield and cheese-making properties of ewe's milk. Small Ruminant Research. 184:1-7. https://doi.org/10.1016/j.smallrumres.2019.106044S17184Albenzio, M., Marino, R., Caroprese, M., Santillo, A., Annicchiarico, G., & Sevi, A. (2004). Quality of milk and of Canestrato Pugliese cheese from ewes exposed to different ventilation regimens. 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Small Ruminant Research, 106(1), 33-35. doi:10.1016/j.smallrumres.2012.04.018González-RodríGuez, M. C., Gonzalo, C., San Primitivo, F., & Cármenes, P. (1995). Relationship Between Somatic Cell Count and lntramammary Infection of the Half Udder in Dairy Ewes. Journal of Dairy Science, 78(12), 2753-2759. doi:10.3168/jds.s0022-0302(95)76906-5Gonzalo, C., Carriedo, J. A., Baro, J. A., & San Primitivo, F. (1994). Factors Influencing Variation of Test Day Milk Yield, Somatic Cell Count, Fat, and Protein in Dairy Sheep. Journal of Dairy Science, 77(6), 1537-1542. doi:10.3168/jds.s0022-0302(94)77094-6Gonzalo, C., Ariznabarreta, A., Carriedo, J. A., & San Primitivo, F. (2002). Mammary Pathogens and Their Relationship to Somatic Cell Count and Milk Yield Losses in Dairy Ewes. Journal of Dairy Science, 85(6), 1460-1467. doi:10.3168/jds.s0022-0302(02)74214-8Gonzalo, C., Tardáguila, J. A., De La Fuente, L. F., & San Primitivo, F. (2004). 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Comparison of Some Indicators of Endogenous Proteolysis in Milk. Journal of Dairy Science, 78(6), 1289-1297. doi:10.3168/jds.s0022-0302(95)76749-2Leitner, G., Chaffer, M., Caraso, Y., Ezra, E., Kababea, D., Winkler, M., … Saran, A. (2003). Udder infection and milk somatic cell count, NAGase activity and milk composition—fat, protein and lactose—in Israeli-Assaf and Awassi sheep. Small Ruminant Research, 49(2), 157-164. doi:10.1016/s0921-4488(03)00079-8Leitner, G., Chaffer, M., Shamay, A., Shapiro, F., Merin, U., Ezra, E., … Silanikove, N. (2004). Changes in Milk Composition as Affected by Subclinical Mastitis in Sheep. Journal of Dairy Science, 87(1), 46-52. doi:10.3168/jds.s0022-0302(04)73140-9Leitner, G., Silanikove, N., & Merin, U. (2008). Estimate of milk and curd yield loss of sheep and goats with intrammamary infection and its relation to somatic cell count. Small Ruminant Research, 74(1-3), 221-225. doi:10.1016/j.smallrumres.2007.02.009Leitner, G., Merin, U., & Silanikove, N. (2011). Effects of glandular bacterial infection and stage of lactation on milk clotting parameters: Comparison among cows, goats and sheep. International Dairy Journal, 21(4), 279-285. doi:10.1016/j.idairyj.2010.11.013Leitner, G., Lavon, Y., Matzrafi, Z., Benun, O., Bezman, D., & Merin, U. (2016). Somatic cell counts, chemical composition and coagulation properties of goat and sheep bulk tank milk. International Dairy Journal, 58, 9-13. doi:10.1016/j.idairyj.2015.11.004Martí-De Olives, A., Le Roux, Y., Rubert-Alemán, J., Peris, C., & Molina, M. P. (2011). Short communication: Effect of subclinical mastitis on proteolysis in ovine milk. Journal of Dairy Science, 94(11), 5369-5374. doi:10.3168/jds.2011-4269Martí De Olives, A., Díaz, J. R., Molina, M. P., & Peris, C. (2013). Quantification of milk yield and composition changes as affected by subclinical mastitis during the current lactation in sheep. Journal of Dairy Science, 96(12), 7698-7708. doi:10.3168/jds.2013-6998Martí-De Olives, A., Navarro-Ríos, M. J., Rubert-Alemán, J., Fernández, N., & Molina, M. P. (2015). Composition, proteolysis indices and coagulating properties of ewe milk as affected by bulk tank somatic cell count. Journal of Dairy Research, 82(3), 344-349. doi:10.1017/s0022029915000394Merin, U., Fleminger, G., Komanovsky, J., Silanikove, N., Bernstein, S., & Leitner, G. (2008). Subclinical udder infection withStreptococcus dysgalactiaeimpairs milk coagulation properties: The emerging role of proteose peptones. Dairy Science and Technology, 88(4-5), 407-419. doi:10.1051/dst:2008022Park, Y. W. (2007). Rheological characteristics of goat and sheep milk. Small Ruminant Research, 68(1-2), 73-87. doi:10.1016/j.smallrumres.2006.09.015Paschino, P., Vacca, G. M., Dettori, M. L., & Pazzola, M. (2019). An approach for the estimation of somatic cells’ effect in Sarda sheep milk based on the analysis of milk traits and coagulation properties. Small Ruminant Research, 171, 77-81. doi:10.1016/j.smallrumres.2018.10.010Pazzola, M., Cipolat-Gotet, C., Bittante, G., Cecchinato, A., Dettori, M. L., & Vacca, G. M. (2018). Phenotypic and genetic relationships between indicators of the mammary gland health status and milk composition, coagulation, and curd firming in dairy sheep. Journal of Dairy Science, 101(4), 3164-3175. doi:10.3168/jds.2017-13975PELLEGRINI, O., REMEUF, F., RIVEMALE, M., & BARILLET, F. (1997). Renneting properties of milk from individual ewes: influence of genetic and non-genetic variables, and relationship with physicochemical characteristics. Journal of Dairy Research, 64(3), 355-366. doi:10.1017/s0022029997002203Pinto, G., Caira, S., Nicolai, M. A., Mauriello, R., Cuollo, M., Pirisi, A., … Addeo, F. (2013). Proteolysis and partial dephosphorylation of casein are affected by high somatic cell counts in sheep milk. Food Research International, 53(1), 510-521. doi:10.1016/j.foodres.2013.05.016Politis, I., Lachance, E., Block, E., & Turner, J. D. (1989). Plasmin and Plasminogen in Bovine Milk: A Relationship with Involution? Journal of Dairy Science, 72(4), 900-906. doi:10.3168/jds.s0022-0302(89)79183-9Precetti, A. S., Oria, M. P., & Nielsen, S. S. (1997). Presence in Bovine Milk of Two Protease Inhibitors of the Plasmin System. Journal of Dairy Science, 80(8), 1490-1496. doi:10.3168/jds.s0022-0302(97)76077-6Raynal-Ljutovac, K., Pirisi, A., de Crémoux, R., & Gonzalo, C. (2007). Somatic cells of goat and sheep milk: Analytical, sanitary, productive and technological aspects. Small Ruminant Research, 68(1-2), 126-144. doi:10.1016/j.smallrumres.2006.09.012Revilla, I., Rodríguez-Nogales, J. M., & Vivar-Quintana, A. M. (2009). Effect of somatic cell counts on ewes’ milk protein profile and cheese-making properties in different sheep breeds reared in Spain. Journal of Dairy Research, 76(2), 210-215. doi:10.1017/s0022029909004002Maristela, R., Natalia, R., Gerardo, C., Jordi, S., & Gabriel, L. (2015). Effect of subclinical intrammamay infection on milk quality in dairy sheep: I. Fresh-soft cheese produced from milk of uninfected and infected glands and from their blends. Small Ruminant Research, 125, 127-136. doi:10.1016/j.smallrumres.2015.02.019Saratsis, P., Alexopoulos, C., Tzora, A., & Fthenakis, G. . (1999). The effect of experimentally induced subclinical mastitis on the milk yield of dairy ewes. Small Ruminant Research, 32(3), 205-209. doi:10.1016/s0921-4488(98)00189-8SCHULTZ, L. H. (1977). Somatic Cells in Milk-Physiological Aspects and Relationship to Amount and Composition of Milk. Journal of Food Protection, 40(2), 125-131. doi:10.4315/0362-028x-40.2.125Silanikove, N., Merin, U., & Leitner, G. (2006). Physiological role of indigenous milk enzymes: An overview of an evolving picture. International Dairy Journal, 16(6), 533-545. doi:10.1016/j.idairyj.2005.08.015Silanikove, N., Merin, U., & Leitner, G. (2014). On effects of subclinical mastitis and stage of lactation on milk quality in goats. Small Ruminant Research, 122(1-3), 76-82. doi:10.1016/j.smallrumres.2014.07.018Vacca, G. M., Cipolat-Gotet, C., Paschino, P., Casu, S., Usai, M. G., Bittante, G., & Pazzola, M. (2019). Variation of milk technological properties in sheep milk: Relationships among composition, coagulation and cheese-making traits. International Dairy Journal, 97, 5-14. doi:10.1016/j.idairyj.2019.05.002Verdi, R. J., & Barbano, D. M. (1991). Effect of Coagulants, Somatic Cell Enzymes, and Extracellular Bacterial Enzymes on Plasminogen Activation. Journal of Dairy Science, 74(3), 772-782. doi:10.3168/jds.s0022-0302(91)78224-6Vivar-Quintana, A. M., Beneitez De La Mano, E., & Revilla, I. (2006). Relationship between somatic cell counts and the properties of yoghurt made from ewes’ milk. International Dairy Journal, 16(3), 262-267. doi:10.1016/j.idairyj.2005.03.00