Enterococcus spp., including E. faecalis and E. faecium, pose risks to dairy farms as opportunistic pathogens. The study evaluates antimicrobial resistance (AMR) and virulence characteristics of Enterococcus spp. isolated from bovine milk. Bile esculin agar was used to assess 1471 milk samples, followed by colony identification, gram staining, catalase tests, and 45 °C incubation. PCR analysis targeted E. faecalis and E. faecium in characteristic Enterococcus spp. colonies, with MALDI-TOF used for negative samples. Multiple tests, including disk diffusion, chromogenic VRE agar for vancomycin resistance, Vancomycin Etest^® for MIC determination, and PCR for virulence factors (cylA, esp, efaA, ace, asa1, gelE, and hyl genes), were performed. Out of 100 identified strains, E. durans (30.66%), E. faecium (26.28%), and E. faecalis (18.25%) were predominant. AMR in Enterococcus spp. varied, with the highest rates against rifampicin (27%), tetracycline (20%), and erythromycin (18%). Linezolid (5%), vancomycin, ciprofloxacin, and teicoplanin (3% each) had lower prevalence. E. faecium and E. faecalis showed high AMR to rifampicin, erythromycin, and tetracycline. Thirty-two strains (18.98%) grew on VRE Chromoselect agar, while 4 (2 E. faecalis and 2 E. faecium) showed vancomycin resistance by MIC values. E. faecalis carried gelE (45.5%) and asa1 (36%), and E. gallinarum had 9.1% with the asa1 gene. Detecting resistant Enterococcus in bovine milk supports control strategies for enterococci on dairy farms, highlighting AMR concerns in the food chain.

The inappropriate use of antimicrobials in dairy animals can lead to residues in raw milk and in dairy products. Foods containing residues of this nature, whether in the short, medium, or long term, cause serious health harm. Absence of these compounds in foods should be a premise for declaring safety. This systematic review aimed to identify the antibiotic residues most frequently found in raw bovine milk and the methodologies used to detect such residues over the ten years from 2013 to 2023. PRISMA guidelines for systematic reviews were followed, by searching the Web of Science, PubMed Central, Scopus, and Springer databases. The search strategy identified 248 articles, and after applying the selection and quality assessment criteria, 16 studies were selected. The number of samples analyzed was 411,530, of which 0.21% tested positive for some type of antibiotic. Eight classes and 38 different types of antibiotics were identified. The most common class was tetracycline, with emphasis on sulfonamides and quinolones, which have shown increasing prevalence among residues in milk in recent years. A total of 56.25% of the studies employed rapid kits to detect residues, 18.75% chromatography, and 25% both techniques. Antibiotic residues in bovine raw milk should be a great concern for animal, environmental, and human health.

Different chilling treatments are used before meat storage. The effect of spray chilling (SC) on meat quality appears to vary. Here, we investigated the effects of SC on beef carcass weight loss and meat quality during subsequent storage. The 2-h SC program tested involved 180-s initial spraying, followed by 60-s spray cycles at 540-s intervals. Deboned chuck tender (IMPS 116B) beef cuts were vacuum-packaged and stored for up to 60 d. Purge and cooking losses, Warner-Bratzler shear force, meat colour [CIE L*, a*, b*], and microbiological quality were evaluated. SC reduced carcass weight loss (P<0.001) compared with conventional chilling. However, storage time affected the purge and cooking losses, and Warner-Bratzler shear force. CIE a* and b* values increased (P<0.05) after 30-d aging in both chilling treatments. Pronounced psychrotrophic growth was observed during storage after both treatments. In conclusion, SC can be used to reduce the economic losses associated with meat chilling, without affecting meat quality attributes.

Escherichia coli is recognized as one of the main microorganisms responsible for triggering clinical mastitis, a disease that causes considerable economic losses in the dairy industry. In this context, this study aimed to identify E. coli isolates present in individual milk samples collected from cows diagnosed with clinical mastitis from various regions of Brazil. Additionally, through polymerase chain reaction (PCR), the presence of virulence genes eae, bfpB, escN, aatA, aggR, ipaH, stx1, stx2, est, and eltA was investigated; all associated with the pathotypes of diarrheagenic Escherichia coli (DEC). As an integral part of the study, a comprehensive assessment of the sensitivity profile of the isolates to 11 different antimicrobials widely used in mastitis treatment was also conducted. A total of 198 milk samples were collected from cows diagnosed with clinical mastitis. Among these samples, 12 isolates (6.07%) demonstrated bacterial growth greater than three Colony-Forming Units (CFU) when grown on MacConkey agar medium and morphological characteristics of E. coli. The disc-diffusion test was used to evaluate the susceptibility of these isolates to antimicrobials, and the most predominant resistance was observed concerning streptomycin and tetracycline, affecting 16.67% of the strains analyzed. Notably, all isolates investigated did not demonstrate the presence of the genes eae, aatA, aggR, ipaH, stx1, stx2, est, and eltA. These results indicate that these isolates do not fit the pathotypes known as diarrheagenic Escherichia coli (DEC). However, one of the isolates tested was positive for the bfpB and escN genes. The detection of resistant E. coli associated with clinical mastitis points to possible gaps in the treatment of the disease. Additionally, the presence of resistance genes in E. coli strains indicates the potential to transmit these genes between animals and, perhaps, along the food chain.

The aim of this study was to evaluate the effect of shading on milk production and milk quality in Girolando cows. A total of 16 Girolando cows were used, divided into two groups for two treatments: the first group remained in a paddock without shade and the second in a paddock with shade. Every 15 days, each group of animals underwent one of the treatments, totaling 120 days of experiment. The 15 days of permanence in each treatment was divided into two periods: 7 days for adaptation and 8 days for sample collection. During the period of data collection, the following variables were measured: the temperature and relative humidity of the air in the paddocks and the milking room; evaluation of the temperature and humidity index; respiratory rate and rectal and superficial temperatures of the skin and udder of the animals; and digital infrared thermographic imaging. Additionally, milk samples were collected for physicochemical evaluation and weighed to assess the daily production of the animals. Descriptive evaluations of the behavior of the animals were carried out, aiming to evaluate the thermal comfort. A cross-over experimental design was used, with an interval between the two treatments. Subsequently, analysis of variance, Pearson’s correlation, and principal component analysis were performed, and the thermographic images were processed in FLIR Tools software to ensure greater precision in relation to surface temperatures. The period of the year during which the animals are kept in sun and shade can affect the average, maximum, and minimum temperatures, the surface temperature of the skin, as well as the temperature and humidity index. It is concluded that, in animals that were subjected to both shaded and unshaded areas, there were correlations among milk constituents and between physiological and environmental variables, without any effect on milk production.