Search

There are limited naturally derived protein biomaterials for the available medical implants. High cost, low yield, and batch-to-batch inconsistency, as well as intrinsically differing bioactivity in some of the proteins, make them less beneficial as common implant materials compared to their synthetic counterparts. Here, we present a milk-derived whey protein isolate (WPI) as a new kind of natural protein-based biomaterial for medical implants. The WPI was methacrylated at 100 g bench scale,95% conversion, and 90% yield to generate a photo-cross-linkable material. WPI-MA was further processed into injectable hydrogels, monodispersed microspheres, and patterned scaffolds with photo-cross-linking-based advanced processing methods including microfluidics and 3D printing. In vivo evaluation of the WPI-MA hydrogels showed promising biocompatibility and degradability. Intramyocardial implantation of injectable WPI-MA hydrogels in a model of myocardial infarction attenuated the pathological changes in the left ventricle. Our results indicate a possible therapeutic value of WPI-based biomaterials and give rise to a potential collaboration between the dairy industry and the production of medical therapeutics.

Yak yogurt, one of the naturally fermented dairy products prepared by local herdsmen in the Qinghai-Tibet Plateau, contains a diverse array of microorganisms. We isolated and identified a novel Streptococcus thermophilus strain, ZJUIDS-2-01, from the traditional yak yogurt. We further purified and carried out detailed structural, physiochemical, and bioactivity studies of an exopolysaccharide (EPS-3A) produced by S. thermophilus ZJUIDS-2-01. The weight-average molecular weight (Mw) of EPS-3A was estimated to be 1.38 × 106 Da by High-Performance Gel Permeation Chromatography (HPGPC). The monosaccharide analysis established its composition to be glucose, galactose, N-acetyl-D-galactosamine, and rhamnose in a ratio of 5.2:2.5:6.4:1.0. The molecular structure of EPS-3A was determined by the combination of permethylation analysis, FT-IR, and NMR spectroscopic techniques. The ζ-potential measurements indicated that EPS-3A had a pKa value of ~4.40. The DSC yielded a melting point (Tm) of 80.4 °C and enthalpy change (ΔH) of 578 J/g for EPS-3A, comparable to those of the xanthan gum (XG), a commercial EPS. EPS-3A exhibited better O/W emulsion stability and flocculating capacity than XG. Furthermore, it also demonstrated similar antioxidant activity to XG and promising in vitro antibacterial properties. This work evidenced that EPS-3A derived from S. thermophilus ZJUIDS-2-01 holds the potential for food and industrial applications.

The current study explored the effect of intramuscular injection of vitamin B12 (VB12) in early-lactation dairy cows on subsequent low-moisture part-skim Mozzarella cheese quality and VB12 levels during cheese processing and storage. Twenty-four peripartum dairy cows were blocked based on parity and milk yield and randomly assigned into 2 treatments: basal diet (CON) and basal diet with an intramuscular injection of 10 mg of VB12 per cow per week (VB12). Raw milk was collected to determine VB12 content and then used to make low-moisture part-skim Mozzarella cheese 8 wk after injection. The VB12 content of raw milk and cheese was determined using ultra-performance liquid chromatography coupled with tandem mass spectrometry. We found that VB12 content was significantly increased in milk (15.43 vs. 3.30 ng/mL) and fresh cheese (3.72 ng/g vs. undetectable) from the VB12 group compared with the CON group. However, approximately 70% of VB12 was lost in the whey during cheese making, and no VB12 was detectable in either cheese treatment after 8 wk of storage. Furthermore, no significant differences were observed in fat and protein contents in the cheese between the 2 groups. For cheese color, the b* value increased and the a* value decreased slightly in fresh VB12 cheese. Functional properties of stretchability, flowability, and meltability of VB12 cheese were initially comparable to that of CON cheese, but higher flowability and meltability was observed in VB12 cheese after 8 wk of storage. In summary, intramuscular injection of VB12 in early-lactation dairy cows increases the content of VB12 in milk and fresh cheese with no adverse effect on cheese quality, but substantial VB12 is lost during cheesemaking and declines rapidly during storage.

Background Probiotics have been reported to reduce total cholesterol levels in vitro, but more evidence is needed to determine the clinical relevance of this activity. Chinese traditional fermented pickles are a good source of lactic acid bacteria. Therefore, pickle samples were collected for screening lactic acid bacteria based on their ability to survive stresses encountered during gastrointestinal passage and cholesterol reducing potency. Results Seventy five lactic acid bacteria strains were isolated from 22 fermented pickles. From these bacteria, Lactobacillus plantarum E680, showed the highest acid (85.25%) and bile tolerance (80.79%). It was sensitive to five of the eight antibiotics tested, inhibited the growth of four pathogenic bacteria, and reduced the total cholesterol level by 66.84% in broth culture. In vivo testing using hypercholesterolemic mice fed high-fat emulsion, independent of food intake, found that L. plantarum E680 suppressed body weight gain and reduced total cholesterol and low-density lipoprotein cholesterol levels, with no effect on high-density lipoprotein cholesterol. Conclusions Chinese traditional fermented pickles are a good source for probiotics. L. plantarum E680, isolated from pickles, was acid and bile tolerant, sensitive to antibiotics, and reduced cholesterol levels both in vitro and in vivo. Based on these results, L. plantarum E680 may have potential as a novel probiotic for the development of cholesterol-lowering functional food.

N-Carbamoylglutamate (NCG) is an enhancer of Arg, which is a functional AA and could prevent cardiovascular disease and improve immunity. The present study was conducted to investigate the effects of supplementing NCG in diets of lactating cattle on the NCG concentration and AA composition of raw milk and on mozzarella cheese quality. Thirty multiparous cows with a mean body weight of 669 kg (standard deviation = 71) and days in milk of 176 (standard deviation = 55) were blocked based on parity and milk production and randomly assigned to 1 of 2 treatments: basal diet (CON) and basal diet supplemented with 40 g of NCG per day per cow (NCG). After 8 wk of treatment, raw milk samples were collected from the 2 groups for AA analysis and mozzarella cheese-making. Furthermore, the NCG concentration and distribution in milk and mozzarella cheese were detected. The AA concentration in milk was greater and the NCG concentration in raw milk was approximately 6 times greater in the NCG group than in the CON group. No NCG was detected in cheese from the CON group, and very little NCG (

This special issue of the Journal of Agricultural and Food Chemistry (JAFC) is a highlight of the Agricultural and Food Chemistry Division (AGFD) technical program at the 258th National Meeting of the American Chemical Society (ACS) in San Diego, CA, U.S.A., on August 25-29, 2019. At the conference, AGFD had 44 oral sessions at 19 symposia and 100 poster presentations with more than 400 abstract submissions. The technical program covered a broad range of current research and development topics in agricultural and food chemistry, including bioactive food components, diet and human nutrition, utilization of agricultural materials in food systems, food packaging, nanotechnology, and food safety, as well as several special award symposia. This is the first JAFC special issue that highlights an ACS national meeting program with joint efforts from AGFD.

Salmonella is an essential food-borne pathogenic microorganism. Humans could get infected by consuming of Salmonella-contaminated foods, especially contaminated meat. In this study, a total of 580 retail meat samples (280 pork, 240 chicken, and 60 goose) were collected from slaughterhouses in Hangzhou to determine the prevalence and antimicrobial susceptibility patterns of Salmonella. Isolates were characterized by serotyping, PFGE (Pulsed-field gel electrophoresis), Polymerase chain reaction (PCR), and antibiotic susceptibility testing. The rates of Salmonella-positive pork, chicken, and goose samples were 21.1% (n = 59), 10.4% (n = 25) and 10.0% (n = 6), respectively. The prevalence of Salmonella was 15.5% in slaughterhouses. Thirteen different Salmonella serovars were identified, and 6 isolates could not be identified. The most commonly prevalent serovars are Salmonella Rissen (S. Rissen) (n = 20, 22.2%), S. Derby (n = 16, 17.8%) and S. Typhimurium (n = 12, 13.3%). The detection rate of the remaining serovars ranged from 1.1%-11.11%. All Derby, Corvallis, and Kentucky strains were from pork. Seventy-two isolates (80.0%) showed drug resistance (DR) to at least one antibiotics, 19 (21.1%) were multi-drug resistant strains, 2 (2.2%) showed seven or more. The detection rate of Trimethoprim/Sulfamethoxazole-resistance (70.0%) was highest, followed by Ampicillin (55.6%). Salmonella resistance was found related to serovar and origin. The positive rates of DR gene sul1, sul2, sul3, class I integrons and bla

Simple Summary The yellow wine lees (YWL), a byproduct of the yellow wine brewing industry which contain high levels of crude protein and anti-oxidative substrates can be a suitable ingredient in dairy rations. Total mixed rations (TMR) containing unfermented/fermented YWL were greater in total phenolic and flavonoid concentrations. Feeding lactating cows under heat stress with TMR containing unfermented or fermented YWL mix can reduce their inflammation response and oxidative stress, as well as improve fatty acid quality and oxidative stability of their milk. Abstract Fifteen multiparous lactating Chinese Holstein dairy cows were used in a replicated 3 × 3 Latin Square Design to evaluate the effect of total mixed rations (TMR) containing unfermented and fermented yellow wine lees (YWL) on the oxidative status of heat-stressed lactating cows and the oxidative stability of the milk and milk fatty acids they produced. Cows were fed with three isonitrogenous and isocaloric diets as follows: (1) TMR containing 18% soybean meal, (2) TMR containing 11% unfermented YWL (UM), and (3) TMR containing 11% fermented YWL (FM). The rectal temperature (at 1300 h) and respiratory rate were higher in control cows than in cows fed UM or FM. Both types of YWL were greater in total phenolic and flavonoid contents, reducing power, and radical scavenging abilities than soybean meal. Cows fed UM or FM had higher blood neutrophil, white blood cell, and lymphocyte counts, as well as lower plasma malondialdehyde level, higher plasma superoxide dismutase, glutathione peroxidase, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate levels, and higher total antioxidant capacity in the plasma than those fed control diet. The proportion of milk unsaturated fatty acids was higher and that of saturated fatty acids was lower in UM- and FM-fed animals than in the control animals. Milk from UM- and FM-fed cows had lower malondialdehyde content but higher 2,2-diphenyl-1-picryl-hydrazyl-hydrate content than the control cows. In conclusion, feeding TMR containing UM and FM to cows reduced both the oxidative stress in heat-stressed cows and improved the oxidative capacity of their milk.

Hypercholesteremia or high cholesterol is one of the important factors leading to atherosclerosis and other cardiovascular diseases. The application of probiotics with cholesterol-lowering characteristics has become increasingly popular over the past decade due to their contribution to human health. This study aimed to evaluate the probiotic effects of Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08 on hyperlipidemic golden hamsters. A hyperlipidemic model was established through a high cholesterol diet in golden hamsters, after which lyophilized Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08 were orally administered individually for 8 weeks. The physiological characteristics of golden hamsters and short chain fatty acid (SCFA) in the colon were assessed by automatic Biochemical Analyzer and gas choromatograph, respectively. A MiSeq sequencing-based analysis of the bacterial 16S rRNA gene (V3–V4 region) in the cecum content was performed to analyze the cecum microbiota. Correlations between sets of these variables were also investigated using the R package “corrplot.” Results showed that neither Lactobacillus fermentum ZJUIDS06 nor Lactobacillus plantarum ZY08 inhibited body weight increase. However, supplementation with Lactobacillus fermentum ZJUIDS06 for 8 weeks increased colon SCFA levels (P < 0.05), decreased serum low-density lipoprotein, total cholesterol, and triglycerides levels, and also induced changes in the cecum microbiota of hyperlipidemic golden hamsters. Remarkably, oral administration of Lactobacillus fermentum ZJUIDS06 increased the relative abundance of Parabacteroides in the cecum, which served as a biomarker for colon SCFA production and improvement of serum cholesterol levels. In a word, Lactobacillus fermentum ZJUIDS06 improved hyperlipidemia in golden hamsters, which correlated with an increase in SCFA levels and relative abundance of Parabacteroides, indicating its potential importance in functional foods that can help lower cholesterol.

The objective of this study was to investigate the levels of aflatoxin M1 (AFM1) concentration in raw milk and dairy products from water buffalo in south China. 136 raw milk and 86 dairy products samples were collected randomly from buffalo dairy pastures and supermarket in Guangxi, Guizhou, Yunnan and Guangdong province of south China during winter season. AFM1 levels were determined using the enzyme linked immunosorbent assay (ELISA) method and verified by high performance liquid chromatography (HPLC). AFM1 was detected in 85 (62.5%) of raw buffalo milk samples, and the content ranged between 4 and 243 ng/kg, among them, 8 (5.9%) samples were over the European Regulation (50 ng/kg). For the dairy products, AFM1 was found in 64 (74.4%) samples, and the content ranged between 4 and 235 ng/kg. AFM1 occurrence (100%) and content (43.1 ng/kg) in cheese was significantly higher than that in high temperature short time (HTST) milk, ultra heat treated (UHT) milk and yogurt. None of the raw milk and dairy products of AFM1 content was over the China standard (500 ng/kg). Therefore, AFM1 contamination in buffalo raw milk and dairy products was not represented a serious public health problem in south China.

This study aimed to investigate the meat quality and safety of chilled pork collected from 45 online stores in China. Total volatile basic nitrogen (TVBN), total viable counts (TVC), and coliform counts of 135 meat samples were analyzed, and the shipment conditions including endpoint temperature, transport time, transport distance and package model were also recorded. Foodborne pathogenic bacteria including Salmonella spp, Staphylococcus aureus (S. aureus), methicillin resistant Staphylococcus aureus (MRSA) and Listeria Monocytogenes (L. monocytogenes) were also detected and counted. The positive rate of Salmonella spp (13.32%), S. aureus (14.81%), MRSA (3.70%) and L. monocytogenes (4.44%) was found for 135 online meat samples. Endpoint temperature is the most important indicator of meat safety; when >10 °C, the unqualified rates for coliform counts, TVC and TVBN were 60%, 40% and 30%, respectively, which were significantly higher than those at

Lactic acid bacteria-derived exopolysaccharides are known for stimulating immune responses. In our previous study, a novel exopolysaccharide (EPS-3A) from skimmed milk fermented by the strain Streptococcus thermophilus (ZJUIDS-2-01) was extracted and structurally characterized. The present study aimed to investigate the effects of EPS-3A on macrophage activation and identify the underlying mechanism. EPS-3A was observed to promote TNF-α secretion and phagocytic uptake. RNA-seq analysis identified 949 differentially expressed genes (DEGs). GO analysis revealed that the DEGs were mainly enriched in metabolic pathways relating to the immune system. PPI network, KEGG pathway, western blot and functional verification assays indicated that MAPK and NF-κB were the key regulators modulating the expressions of the core gene TNF-α. Role and function of TLR2 and TLR4 for the recognition of EPS-3A were also determined. In conclusion, EPS-3A activated macrophages through MAPKs and NF-κB signaling mediated at least partly via TLR2 and TLR4.

This present study was designed to test the protective role of two Lactobacillus plantarum strains, E680 and ZY08, against alcoholic liver disease (ALD) in C57BL/6 mice. The ALD mouse model was established by exposing the mice to a Lieber-DeCarli ethanol liquid diet. The two probiotic strains (10

Hypercholesteremia or high cholesterol is one of the important factors leading to atherosclerosis and other cardiovascular diseases. The application of probiotics with cholesterol-lowering characteristics has become increasingly popular over the past decade due to their contribution to human health. This study aimed to evaluate the probiotic effects of Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08 on hyperlipidemic golden hamsters. A hyperlipidemic model was established through a high cholesterol diet in golden hamsters, after which lyophilized Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08 were orally administered individually for 8 weeks. The physiological characteristics of golden hamsters and short chain fatty acid (SCFA) in the colon were assessed by automatic Biochemical Analyzer and gas choromatograph, respectively. A MiSeq sequencing-based analysis of the bacterial 16S rRNA gene (V3–V4 region) in the cecum content was performed to analyze the cecum microbiota. Correlations between sets of these variables were also investigated using the R package “corrplot.” Results showed that neither Lactobacillus fermentum ZJUIDS06 nor Lactobacillus plantarum ZY08 inhibited body weight increase. However, supplementation with Lactobacillus fermentum ZJUIDS06 for 8 weeks increased colon SCFA levels (P < 0.05), decreased serum low-density lipoprotein, total cholesterol, and triglycerides levels, and also induced changes in the cecum microbiota of hyperlipidemic golden hamsters. Remarkably, oral administration of Lactobacillus fermentum ZJUIDS06 increased the relative abundance of Parabacteroides in the cecum, which served as a biomarker for colon SCFA production and improvement of serum cholesterol levels. In a word, Lactobacillus fermentum ZJUIDS06 improved hyperlipidemia in golden hamsters, which correlated with an increase in SCFA levels and relative abundance of Parabacteroides, indicating its potential importance in functional foods that can help lower cholesterol.

Decontamination of fresh meats without negatively impact on their sensory quality is a big challenge. In this study, the single or combined effect of antimicrobials (chitosan, carvacrol, tea polyphenols) and low dose gamma irradiation (≤2 kGy) against Salmonella Typhimurium and Staphylococcus aureus on fresh pork meat were assessed. The effects of these treatments on the color and lipid oxidization of pork meat were also evaluated. Irradiation at 1 kGy reduced 2.2 logs of S. Typhimurium and 1.6 logs of S. aureus, while the treatments of 1 kGy irradiation combined with chitosan (1%)-carvacrol (0.2%) or chitosan (1%)-tea polyphenols (0.5%) achieved 3.2 log reduction of S. Typhimurium and 5.1 log reductions of S. aureus. Irradiation at 2 kGy in combination with chitosan-carvacrol obtained over 5 log reductions of S. Typhimurium and S. aureus. There was no recovery/regrowth of S. Typhimurium or S. aureus in vacuum packaged meat samples throughout the 14 d storage period. There were no significant differences among all meat samples in color (L*, a*, b* values) after 7 d, while the combined treatments increased the lightness (L*) after 14 d of storage at 4 °C. The treated meat samples had lower content of malondialdehyde, indicating less lipid oxidation in pork meat during storage. This study demonstrates that the combined low dose irradiation with these antimicrobial surface treatments is promising for improving fresh pork safety and quality.

This study aims to investigate the occurrence of aflatoxin B1 (AFB1) in total mixed rations (TMR) and aflatoxin M1 (AFM1) in raw and commercial milk in northern China during winter season. A total of 22 feed samples, as well as the corresponding 84 raw milk and 69 commercial milk samples were randomly collected from northwest, northeast and north areas of China from November 2019 to January 2020. High performance liquid chromatography and enzyme linked immunosorbent assay method were applied to detect AFB1 and AFM1. All samples presented AFB1 (30–370 ng/L) and AFM1 (10–430 ng/L) levels under the legal limit of China for raw milk (10 μg/L) and commercial milk (500 ng/L). While 31.8% of TMRs and 34.5% of raw milk samples exceeded the European Union (EU) legal limit for AFM1 in raw milk (5 μg/L) and commercial milk (50 ng/L). Compared with the samples from northeast and north areas of China with the similar AFB1 concentration, samples from northwest area of China exhibited higher AFM1 level (mean = 130 ng/L), thus presenting a higher transfer ratio from AFB1 to AFM1. A Linear relationship was observed between AFB1 in TMRs and AFM1 in raw milk. In conclusion, all samples from northern China presented AFB1 and AFM1 levels under Chinese legal limit and only about 30% of the tested samples exceeded the EU legal limit. However, the aflatoxin contamination in northwest area of China should be paid more attention to due to the high AFM1 levels and high variance in milk samples.

The polymorphism of buffalo α

Milk fat globule membrane (MFGM) proteins contribute to human nutrition and health. However, differences in MFGM proteome among the buffalo breeds are unknown. In this study, MFGM proteins from Murrah, Nili-Ravi and Mediterranean buffaloes were identified using a tandem mass tag proteomic approach to characterize the components and their potential activities. A total of 1258 MFGM proteins were identified and 103 differentially expressed proteins were found in the studied buffalo breeds. Of these, toll-like receptor 2 had higher abundance in Mediterranean milk; endoplasmic reticulum resident protein 29 had higher levels in Nili-Ravi milk; uromodulin had higher abundance in Murrah milk. A number of 781 newly proteins in buffalo milk exerted antioxidant, antibacterial, and anti-inflammatory activities. Our findings reveal the component complexity and functional diversity of MFGM proteins in different buffalo breeds. Thus, our data may path the way to promote raw buffalo milk as a healthy and functional dairy product.

The polymorphism of buffalo αs1-casein has been reported, but little is known about their effect on the biological properties. The objective of this study was to investigate the effect of αs1-casein polymorphism on the digestive properties and bioactivities of buffalo milk protein in simulated gastrointestinal digestion. In this study, two variants of αs1-casein, with one amino acid substitution of Leu193 (AA) → Ser193 (BB), were used. Under acidic gastric conditions, the particle size of αs1-casein variant BB was smaller and showed higher digestibility compared to variant AA. A total of 154 and 149 peptides were identified, respectively, from simulated gastrointestinal digestion of variants AA and BB; of three peptides have been previously reported to exert ACE-inhibition, anticancer, antioxidant, and anxiolytic activities. Our study demonstrated that αs1-casein polymorphism affects the digestive properties and the formation of bioactive peptides.

The effect of homogenization alone or in combination with high-temperature, short-time (HTST) pasteurization or UHT processing on the whey fraction of milk was investigated using highly sensitive spectroscopic techniques. In pilot plant trials, 1-L quantities of whole milk were homogenized in a 2-stage homogenizer at 35°C (6.9 MPa/10.3 MPa) and, along with skim milk, were subjected to HTST pasteurization (72°C for 15 s) or UHT processing (135°C for 2 s). Other whole milk samples were processed using homogenization followed by either HTST pasteurization or UHT processing. The processed skim and whole milk samples were centrifuged further to remove fat and then acidified to pH 4.6 to isolate the corresponding whey fractions, and centrifuged again. The whey fractions were then purified using dialysis and investigated using the circular dichroism, Fourier transform infrared, and Trp intrinsic fluorescence spectroscopic techniques. Results demonstrated that homogenization combined with UHT processing of milk caused not only changes in protein composition but also significant secondary structural loss, particularly in the amounts of apparent antiparallel β-sheet and α-helix, as well as diminished tertiary structural contact. In both cases of homogenization alone and followed by HTST treatments, neither caused appreciable chemical changes, nor remarkable secondary structural reduction. But disruption was evident in the tertiary structural environment of the whey proteins due to homogenization of whole milk as shown by both the near-UV circular dichroism and Trp intrinsic fluorescence. In-depth structural stability analyses revealed that even though processing of milk imposed little impairment on the secondary structural stability, the tertiary structural stability of whey protein was altered significantly. The following order was derived based on these studies: raw whole>HTST, homogenized, homogenized and pasteurized>skimmed and pasteurized, and skimmed UHT>homogenized UHT. The methodology demonstrated in this study can be used to gain insight into the behavior of milk proteins when processed and provides a new empirical and comparative approach for analyzing and assessing the effect of processing schemes on the nutrition and quality of milk and dairy product without the need for extended separation and purification, which can be both time-consuming and disruptive to protein structures.

Understanding the milk protein expression profile in different buffalo breeds plays an important role in improving hybrid selection and determining the effects on milk protein synthesis. The aim of this research is to compare the differences in milk protein content, composition and distribution between River buffalo and their crossbreeds for hybrid screening. Four groups of milk samples that included Nili-Ravi (N), Murrah (M), a Nili-Ravi-Murrah crossbreed (M-N), and a crossbreed of river buffalo with local swamp buffalo (C) were collected. The protein composition of the buffalo milk was determined by RP-HPLC. A gel-based proteomic approach consisting of two-dimensional gel electrophoresis coupled with mass spectrometry was utilised for the detailed protein characterisation of milk from different breeds. The results of this analysis showed that the river/swamp buffalo crossbreed (C) displayed the highest content of total protein (4·46%) and κ-casein (11·14%) but the lowest content of α-lactalbumin (6·79%). By selecting 23 different protein spots among the four types of milk that contained the most spots corresponding to κ-casein, β-casein and αs1-casein, correlations between the crossbreeds, protein polymorphism and phosphorylation could be made. The results of this study indicate that crossbreeding a swamp buffalo with a river buffalo has a notable effect on the protein content and composition that may be exploited for producing high-quality raw milk in food technology applications and dairy food production.

The effect of refrigeration on bacterial communities within raw and pasteurized buffalo milk was studied using high-throughput sequencing. High-quality samples of raw buffalo milk were obtained from 3 dairy farms in the Guangxi province in southern China. Five liters of each milk sample were pasteurized (72°C; 15 s); and both raw and pasteurized milks were stored at refrigeration temperature (1-4°C) for various times with their microbial communities characterized using the Illumina Miseq platform (Novogene, Beijing, China). Results showed that both raw and pasteurized milks contained a diverse microbial population and that the populations changed over time during storage. In raw buffalo milk, Lactococcus and Streptococcus dominated the population within the first 24h; however, when stored for up to 72h the dominant bacteria were members of the Pseudomonas and Acinetobacter genera, totaling more than 60% of the community. In pasteurized buffalo milk, the microbial population shifted from a Lactococcus-dominated community (7d), to one containing more than 84% Paenibacillus by 21d of storage. To increase the shelf-life of buffalo milk and its products, raw milk needs to be refrigerated immediately after milking and throughout transport, and should be monitored for the presence of Paenibacillus. Results from this study suggest pasteurization should be performed within 24h of raw milk collection, when the number of psychrotrophic bacteria are low; however, as Paenibacillus spores are resistant to pasteurization, additional antimicrobial treatments may be required to extend shelf-life. The findings from this study are expected to aid in improving the quality and safety of raw and pasteurized buffalo milk.

This study was conducted to compare the volatile and fatty acid (FA) components between rams and ewes and between perirenal (PF) and subcutaneous adipose tissues (SF). The SF and PF were sampled from 24 Hu sheep. Volatile compounds and FAs were evaluated by gas chromatography–mass spectrometry. Data analysis was performed by principal component analysis. A total of 55 volatiles and 19 fatty acids were identified. Ewes had more aldehydes and less total unsaturated and monounsaturated FAs than did rams, and more aldehydes, total unsaturated and monounsaturated FAs were found in SF than in PF. Aldehydes and unsaturated FAs were closely related with the distinction between ram SF and PF. It is inferred that volatile compound profiles are different between genders and fat sites, with aldehydes as the main contributor, and that aldehydes are related to unsaturated FA contents in Hu sheep.

This study was aimed to investigate the effects of fish oil supplementation on production of CLA species, and accumulation of trans-11 C18:1 and trans-10 C18:1 in the rumen. Ruminal fluid was collected from goats, diluted in acidic incubation buffer, and then incubated with a mixture of dry grass and concentrate supplemented with soybean oil and different amounts of fish oil (0, 50, and 100 mg for the control, LFO, and HFO groups, respectively). Incubation was carried out anaerobically at 39 °C for 24 h, and fatty acid composition was analyzed by chromatography at different time points. Although it showed initial inhibitory effects at earlier time points, fish oil significantly increased cis-9, trans-11 CLA content at 24 h. At the same time, it inhibited trans-10, cis-12 CLA content dose-dependently with significant effect at 16 and 24 h. Fish oil also increased trans-11 C18:1 content significantly (P

The performance of a Loop-mediated isothermal amplification (LAMP) assay for detecting food-borne pathogen Listeria monocytogenes was presented in this paper. Three pairs of primers were specially designed for recognizing eight distinct sequences of iap gene (P60 extracellular protein, invasion associated protein IAP). Time and temperature conditions for amplification of L. monocytogenes were optimized to be 40 min at 63C. Detection limit level for artificially contaminated raw milk samples by the LAMP assay was 186 cfu/mL corresponding to 8–10 cells per reaction tube, while the detection level by conventional PCR was 1.86 × 105 cfu/mL. Data on natural raw milk samples indicated that the LAMP method was highly specific and sensitive, giving 91.67% concordance with the ISO 10560 reference method for the samples without enrichment and 100% concordance after enrichment. PRACTICAL APPLICATION The LAMP method in this paper provided a powerful tool with the specificity, sensitivity and rapidity for detection of Listeria monocytogenes in raw milk.

In the present study, we report the performance of a loop-mediated isothermal amplification (LAMP) assay detecting foodborne pathogen Escherichia coli O157. Three pairs of primers were specially designed for recognizing eight distinct sequences of rfbE gene. Time and temperature conditions for amplification of E. coli O157 were optimized to be 40 min at 65C. The LAMP assay gave artificially contaminated raw milk sample detection limit level of 410 cfu/mL which corresponds to three to five cells per reaction tube, while the detection level of conventional polymerase chain reaction was 4.1 × 104 cfu/mL. Data on naturally contaminated raw milk samples indicated that the LAMP method was highly specific and sensitive, giving 100% concordance with the ISO 16654: 2001 reference method. PRACTICAL APPLICATIONS The loop-mediated isothermal amplification method reported here provides a powerful tool for the detection of Escherichia coli O157 in raw milk samples because of its specificity, sensitivity and rapidity.

In the present study, the effect of feed Se supplementation on the Se content of raw milk and mozzarella cheese as well as the effect on cheese quality and functionality were determined. The Se milk was produced by supplying dairy cow feed with Se yeast (0.3mg of Se/kg of dry matter), resulting in a Se concentration in milk of 35.81μg/L. The fat, casein, and whey protein of Se milk were separated by ultracentrifugation, and the Se content was determined by atomic absorption spectroscopy. The Se distribution in different milk fractions of fat, casein, and whey protein were 9.82, 45.56, and 44.62%, respectively. The Se mozzarella cheese was made by Se milk, and the composition and texture of Se cheese did not significantly differ from that of the control. However, the functional properties (meltability, flowability, and stretchability) of the Se cheese were better after 8 wk of storage. Moreover, the pH and water activity were lower in Se cheese, which decreased the total plate count. The Se content in mozzarella cheese was 4 fold higher than that in milk, and Se was found in the whey, hot water, and brine collected during cheesemaking. Organic and inorganic Se was found in the Se cheese after 8 wk of storage, and most Se peptides detected after storage were Se-Met and Se-Cys. The results of this study show that feed Se supplementation can improve the Se content of milk and cheese without affecting mozzarella cheese quality.

Bovine beta-lactoglobulin is one of the first foreign antigens encountered by some newborn children, and it has been described as the main allergenic protein in cow's milk even when present at low concentration.Enzymatic hydrolysis has been identified to be a very effective way to reduce the sensitization of beta-lg compared to other treatments. The aim of this study was to explore whether enzymatic hydrolysis could reduce the allergenicity of native bovine beta-lg.beta-lg was hydrolyzed by trypsin. Twenty four BALB/c mice were divided into three groups and orally sensitized by native bovine beta-lg and its hydrolysates five times at weekly intervals.During the sensitization period, many serious systemic anaphylactic symptoms were observed in mice sensitized by native beta-lg compared to hydrolysates of beta-lg. Mice sensitized by hydrolysates of beta-lg showed a significantly lower spleen lymphocyte proliferation level than intact beta-lg. The beta-lg-specific IgE antibody levels in serum and intestinal fluid samples induced by native beta-lg were significantly elevated. Plasma histamine levels were also evaluated and showed the same trend as IgE. Moreover, the hydrolysates of beta-lg significantly up-regulated IFN-gamma and IL-10 production and down-regulated IL-4 and IL-5 secretions by murine splenocytes.These results suggested that enzymatic hydrolysis could partly reduce the allergenicity of beta-lg.