Search

The study investigated potential changes in bioactive milk proteins in relation to the season, breed, farm and udder health status. Nine hundred and sixty bulk milk samples from 12 commercial farms in northwest China were collected during 2020–2021. Six bioactive proteins including fraction of β‐casein proteins, α‐lactalbumin, β‐lactoglobulin, lactoferrin (Lf) and osteopontin were evaluated. It was found that most proteins (with exception of β‐casein A1) of Jersey cows are significantly higher than Holstein cows. Most bioactive proteins demonstrated seasonal variation, and some exhibited geographical variation (with exception of whey albumins). The milk somatic cell count showed a positive correlation with immune proteins such as Lf. [ABSTRACT FROM AUTHOR]

A novel microextraction method was developed by combining CO2-controlled switchable hydrophilicity solvent (SHS) with solidification of the aqueous phase (SAP), referred to as CSHS-SAP. It was applied for pre-concentration/extraction of the complexes of Pb-ammonium pyrrolidine dithiocarbamate (APDC) prior to GFAAS detection in raw bovine milk and milk products (whole-fat, half-skimmed and skimmed milks). In the CSHS-SAP microextraction, a clear interface was easily formed, and convenient and complete collection was achieved by directly transferring the SHS phase into a vial, which overcame the shortcomings of blurred interface and difficult collection of SHS phase using CSHS-based microextraction. SAP led to the increase of extraction recoveries for Pb2+ by 8–11%. Some important factors were optimised using a one-factor-at-a-time approach: 800 µL of N,N-dimethylbutylamine and water at a ratio of 1:1 as SHS, 1.0 g L−1 APDC as chelating agent, sample pH = 6.0, 0.6 mL of 1.0 mol L−1 NaOH, solidification time of 70 min and 300 µL of 0.5 mol L−1 HNO3 for back extraction. Under optimised conditions, limits of detection were as low as 0.01–0.02 µg kg−1 and enrichment factors reached more than 23-fold. Inter- and intra-day precisions had relative standard deviations of 3.6–6.4%. With the CSHS-SAP/GFAAS method Pb2+ was detected at 0.5–1.8 µg kg−1 in four bovine raw milk samples, which were collected from Hubei and Henan Provincial oil-producing area, China. However, Pb2+ was below the LOD in all of the local milk products. Overall, the newly developed CSHS-SAP/GFAAS method is convenient, efficient and robust, giving it great potential for rapid and accurate analysis of trace Pb2+ in liquid milks. [ABSTRACT FROM AUTHOR]

Background: Diseases caused by livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) are an important global public health concern, and MRSA is increasingly being isolated in bovine milk. However, information on the genotype and antimicrobial resistance of MRSA in bovine milk in Xinjiang is limited. The objective of this study was to determine the antimicrobial-susceptible phenotypes and genotypes of the circulating MRSA clone isolated in bovine mastits milk samples in Xinjiang, China., Methods: Fifty six MRSA isolates collected from milk of bovine mastitis were investigated by multilocus sequence typing (MLST), staphylococcal protein A (spa) typing, and a minimum inhibitory concentration test with 21 antimicrobial agents., Results: Antibiotic resistance results showed that 47.4% of the isolates were resistant to 16 or more antibiotics. Twelve MLST types were defined in this study, and ST398 (n = 7) and ST2393 (n = 2) were found to be the most prevalent types. Seven spa types (t034, t269, t4030, t114, t35, t189, and t7589) were identified, of which t034 (n = 7), t189 (n = 3), and t4030 (n = 3) were predominant. Here, 3 MRSA ST188 is reported among human MRSA isolates in China, and this is the first time that it is reported in bovine MRSA strains., Conclusions: The antimicrobial susceptibility of MRSA in this area exhibited multidrug resistance, and clonal complexes CC398 and CC188, which have been reported among human MRSA isolates, do occur in Xinjiang dairy cows. This study provides a foundation for further MRSA monitoring.

The identification and localization of organic binders in artworks are big challenges in archaeology and conservation science. Immunological techniques, such as enzyme-linked immunosorbent assay (ELISA) and immunofluorescence microscopy (IFM) have the potential to become powerful tools for the analysis of organic materials in ancient samples. In this study, ELISA and IFM techniques were combined to identify chicken ovalbumin, glue from several mammalian species, bovine milk, and fish glue in ancient Chinese painting samples. As binders, egg ovalbumin was found in two painting samples and animal glue was found in three samples, which were dated from the 4th to 8th centuries. The results clearly demonstrate that ELISA and IFM can be used to validate results from ancient samples.