Relationship between cell counts in bovine milk and the presence of mastitis pathogens (yeasts and bacteria)

Bovine Colostrum for Human Consumption—Improving Microbial Quality and Maintaining Bioactive Characteristics through Processing

The main purpose of bovine colostrum, being the milk secreted by a cow after giving birth, is to transfer passive immunity to the calf. The calves have an immature immune system as they lack immunoglobulins (Igs). Subsequently, the supply of good quality bovine colostrum is required. The quality of colostrum is classified by low bacterial counts and adequate Ig concentrations. Bacterial contamination can contain a variety of human pathogens or high counts of spoilage bacteria, which has become more challenging with the emerging use of bovine colostrum as food and food supplements. There is also a growing risk for the spread of zoonotic diseases originating from bovines. For this reason, processing based on heat treatment or other feasible techniques is required. This review provides an overview of literature on the microbial quality of bovine colostrum and processing methods to improve its microbial quality and keep its nutritional values as food. The highlights of this review are as follows: high quality colostrum is a valuable raw material in food products and supplements; the microbial safety of bovine colostrum is increased using an appropriate processing-suitable effective heat treatment which does not destroy the high nutrition value of colostrum; the heat treatment processes are cost-effective compared to other methods; and heat treatment can be performed in both small- and large-scale production.

Resistência a antimicrobianos em Staphylococcus aureus isolados de mastite em bovinos leiteiros de Minas Gerais, Brasil

Staphylococcus aureus (S. aureus) destaca-se como um dos agentes etiológicos mais frequentes da mastite bovina, que causa os maiores prejuízos econômicos à pecuária leiteira brasileira. Visando avaliar o perfil de sensibilidade deste agente aos antimicrobianos, 352 isolados provenientes de 35 rebanhos leiteiros localizados em Minas Gerais foram submetidos a testes de antibiograma, utilizando-se a técnica de difusão em disco. Nitrofurantoína, bem como as associações de neomicina, bacitracina e tetraciclina (NBT) e penicilina, nafcilina e dihidroestreptomicina (PND), apresentaram 100% de eficiência in vitro. Foram verificados baixos índices de resistência no grupo das cefalosporinas, com valores de 0, 0,28 e 0,40% para cefquimona, cefalotina e ceftiofur, respectivamente. Entre os aminoglicosídeos, observou-se 1,69% de resistência para gentamicina e 3,35% para a neomicina. O maior índice de resistência foi observado para polimixina B (82%), seguido pelos betalactâmicos, ampicilina e penicilina, com índices de resistência de 80,92 e 80,45%, respectivamente. Níveis intermediários de resistência foram observados para tetraciclina, lincomicina, cefoperazona e sulfazotrim. Entre os isolados testados, 65 (18,15%), oriundos de 24 dentre os 35 rebanhos estudados, apresentaram multirresistência (índice MAR ≥ 0,2). Os resultados apontaram grande variação nos perfis de resistência aos antimicrobianos, assim como a ocorrência de múltipla resistência entre algumas cepas estudadas, salientando a necessidade de testes de antibiograma para a escolha dos antimicrobianos mais adequados para o tratamento ou prevenção de mastite causada por S. aureus.

Udder disease etiology, milk somatic cell counts and NAGase activity in Israeli Assaf sheep throughout lactation

Bacterial pathogens causing udder infections in Israeli Assaf dairy sheep were identified and changes occurring throughout lactation were monitored to study the correlation between the contaminant and the severity of the infection, as measured by somatic cell count (SCC) and NAGase tests. A total of 159 Israeli Assaf dairy sheep on one farm, in their first (69), second (13) or third and more (77) lactations were included in this study. Udder halves were tested for bacterial condition, SCC and NAGase activity 2-3 weeks post lambing and every 4 weeks after until drying-off. At first sampling, in 60.7% (193/318 quarters) of the halves no bacterial growth (NBG) was detected. Different species of coagulase negative staphylococci (CNS) were the main pathogen group in infected udders. Streptococci were isolated from 14 halves, most of them in the two udder halves. The percent of udder infection in sheep in their third or further lactations was 2.8 greater (P<0.05) than in that of sheep in their first lactation. During the lactation, 90.6% of the halves did not change their classification status, suggesting that most infections occur before lambing and/or during the following first few days. The arithmetic mean of SCC and NAGase of total half udder milk and samplings (during the lactation) were 1144+/-48x10(3)cells/ml and 49.4+/-2.5, respectively. The average SCC in the milk of halves classified as NBG was 321+/-35x10(3)cells/ml and was not significantly changed during the lactation period. In halves infected with CNS, average SCC was 1371+/-150x10(3)cells/ml at the first testing and increased to 2129+/-347x10(3)cells/ml at drying-off. No significant differences were found in SCC and NAGase activity between the different species of the CNS. The mean SCC over the types of bacteria isolated, lactation number and days in lactation was significantly different (P<0.0001). In 4% of the halves, from all samples, SCC was above 5000x10(3)cells/ml although no bacteria were detected in their milk. The higher SCC in the CNS infected halves contrasted with the more moderate SCC found in dairy cows similarly infected, suggesting that the sheep udder has a lower resistance and an augmented immunological response against this group of bacteria. Thus, this should be considered accordingly in schemes for sheep's milk quality payment.

Isolation of Candida rugosa from turkeys

The present study describes the isolation of Candida rugosa from young turkeys that died 10 days after the end of a therapeutic treatment for a recent outbreak of coccidiosis. Candida rugosa was isolated from the digestive tract of all the birds examined. This isolation is the first in turkeys and corroborates the fact that C. rugosa is an opportunistic yeast which circumvents host defences when other predisposing factors are present.