Effects of the level of feed intake and ergot contaminated concentrate on ergot alkaloid metabolism and carry over into milk

The aim of the present study was to examine the effects of ergot contaminated concentrate at differing levels of feed intake on ergot alkaloid metabolism and carry over into milk. Twelve double fistulated (in the rumen and the proximal duodenum) Holstein Friesian cows were fed either the control diet (on a dry matter (DM) base: 60% maize silage, 40% concentrate) or the contaminated diet (concentrate contained 2.25% ergot, which caused an alkaloid concentration of the daily ration between 504.9 and 619.5 μg/kg DM) over a period of 4 weeks. Daily feed amounts were adjusted to the current performance which resulted in a dry matter intake (DMI) variation between 6.0 and 18.5 kg/day. The actual alkaloid exposure varied between 4.1 and 16.3 μg/kg body weight when the ergot contaminated concentrate was fed. Approximately 67% of the alkaloids fed were recovered in the duodenal ingesta, and ～?24% were excreted with the faeces. No alkaloid residues could be detected in the blood or milk samples.     

Transfer of perfluorooctane sulfonic acid (PFOS) from contaminated feed to dairy milk

Dietary intake is the predominant route for human exposure to perfluorooctane sulfonic acid (PFOS). Single pollution events may thus affect human exposure if polluted ground and water is used to produce animal feed or food. In this study, a physiologically based pharmacokinetic (PBPK-) model is derived that describes the uptake of PFOS from contaminated feed by cows and its subsequent elimination through the cows’ milk. Parameter values of the model were estimated by fitting to experimental data of a cow feeding trial. Model calculations showed that almost all PFOS ingested is excreted through the cows’ milk. The elimination rate, however, was low as the estimated half-life in the cow was 56 days and it may, thus, take a long time after an initial pollution event to produce PFOS-free milk. The derived model can be used to estimate the transfer of PFOS through the dairy food chain and can be used for comparison of various contamination routes.     

Milking and milk processing: traditional technologies in the yak farming system of the Qinghai-Tibetan Plateau, China

Yak milk and its products are widely consumed by local herders and are regarded as the resources of economic income by the households on the Qinghai-Tibetan Plateau. Yak raisers have developed their own milking skills and milk-processing technologies through a long history of yak keeping. All of these traditional skills and technologies have their own characteristics. In this paper, the methods and procedures of milking and milk processing in yak farming systems are reviewed.     

The potential for scale economies in milk powder processing: an Irish case study

This paper examines the difference in costs associated with milk plants of differing dryer scale in Ireland. This is an important question for international competitiveness in the context of the removal of the EU milk quota in 2015 and the expectation that Irish milk production could increase considerably thereafter. Using confidential data obtained from a number of sources, the differential in the cost of processing at differing plant scales was established. It was found that two 7.5 tonne/h dryers at a single location provide a level flexibility which offsets the slight cost advantage associated with a 15 tonne/h dryer.     

Quantification of cadmium and lead in offal by SF-ICP-MS: Method development and uncertainty estimate

Offal of bovine, ovine and porcine are able to accumulate potentially toxic heavy metals, such as Cd and Pb, posing a risk for human health. For this reason, the Commission Regulation no. 466/2001 provided the maximum admitted levels for these metals in this kind of matrix (Cd, 500 ng g⁻¹ in all kinds of offal; Pb, 500 ng g⁻¹ in liver and 1000 ng g⁻¹ in kidney). A method based on sector field inductively coupled plasma mass spectrometry for Cd and Pb quantification in calf liver was developed and further applied to offal of different animals. The uncertainty of measurements was calculated according to the Eurachem/Citac Guide. The method LoDs and LoQs were 3.5 and 11 ng g⁻¹ for Cd, and 2.0 and 6.0 ng g⁻¹ for Pb. The repeatability and the intra-laboratory reproducibility showed relative standard deviations equal to 2.25% and 1.99% for Cd and 1.49% and 6.55% for Pb. Relative expanded uncertainties at the mean value in calf liver were 4.74% for Cd and 13.8% for Pb. In Italian offal the following concentration intervals were found (in ng g⁻¹): (i) Cd: calf, from <3.5 in spleen and lung to 96.4 in kidney; lamb, <3.5 in all offal; pig, 114 in liver and (ii) Pb: calf, from 4.03 in lung to 31.8 in liver; lamb, from 4.71 in heart to 279 in liver; pig, 9.19 in liver.     

Persistent organochlorine pesticide residues in milk and dairy products in India

Monitoring of milk and dairy product samples of various brands from different cities in Maharashtra, India, was carried out to determine if there is any contamination due to organochlorine pesticide residues. The measurements were made using a gas chromatograph-electron capture detector system. Trace levels of DDT and HCH were detected in the samples. Total HCH levels in milk and milk product samples were lower than total DDT levels, which could be attributed to earlier extensive antimalaria sanitary activities. Butter had higher levels of DDT than cheese and milk powder. All levels of organochlorine pesticide residues in milk and milk products were well below the maximum permissible limits given by the FAO/WHO. More importantly, as compared with an earlier report, present levels of the contaminants are substantially lower, which indicate the gradual phase out of these compounds.     

Polycyclic aromatic hydrocarbons in milk and dairy products

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with a structure consisting of carbon and hydrogen atoms that have more than two fused aromatic rings. Most PAHs have carcinogenic effects on animal or humans and induce various cancers. Polycyclic aromatic hydrocarbons are a consequence of environmental pollutants, imperfect burning or pyrolysis of organic substances during industrial processing. Additionally, foods can be contaminated during their processing and preparation through different heat treatments. This review highlights the formation, occurrence and health impacts of PAHs in milk and milk products, and analytical technique used for their determination in dairy products.     

Survey of aflatoxin M1 in milk and dairy products consumed in Burdur,Turkey

The aim of this study was to investigate the occurrence of aflatoxin M₁ (AFM₁) in dairy product samples in Burdur city. A total of 315 samples of dairy products were collected during 2008. Of the 315 samples analysed, AFM₁ in 246 samples (78.1%) was found to range from 5.5 to 800 ng/kg. In addition, AFM₁ levels of 16 raw milk, two pasteurised milk, only one milk powder and three white cheese samples were above the Turkish Food Codex. It is concluded that the occurrence of AFM₁ in dairy products may be considered as a possible hazard for public health.     

Multiple sclerosis and milk: to drink or not to drink?

Multiple sclerosis (MS) is a condition of the central nervous system. It is the most common disabling neurological disease among young adults. The aetiology of this condition, which affects approximately 85 000 people in the UK, is unknown. It has been suggested that environmental factors including nutrition may be involved in its development in susceptible individuals. In the past, it has been suggested that milk and dairy products could exacerbate, cause relapses in, and even progress the symptoms of MS. This paper discusses the role of dairy products and their components in relation to MS, and is based on recently published research.     

Flowability and wetting behaviour of milk protein ingredients as influenced by powder composition,particle size and microstructure

This work aimed to provide a comprehensive characterisation of several physicochemical properties of different milk protein powders frequently used as ingredients in dairy‐based food formulations, in particular flowability and wettability. The flow and wetting properties were influenced mainly by the powder composition, less than by other physicochemical properties, such as particle size and microstructure. Powders with high fat content had poor flow and wetting properties. The wetting properties were also influenced by the protein content (mainly by the casein content) of the powders and were poor for powders having poor release of ionic calcium.     

Detection of aflatoxin M1 in milk and dairy products consumed in Adana, Turkey

A total of 70 dairy products consisting of 20 sterilized milk, 10 butter, 20 white cheese and 20 Kashar cheese samples were analysed for aflatoxin M₁ (AFM₁) by enzyme-linked immunosorbent assay (ELISA). The detection limit was 5 ng/L for milk and 25 ng/kg for butter, white cheese and Kashar cheese. Of the 70 dairy products analysed, AFM₁ in 49 samples (70%) was found to range from 10 to 388 ng/kg. Moreover, AFM₁ levels in three samples of milk, two samples of butter, one sample of white cheese and one sample of Kashar cheese were found to be higher than the Turkish legal limits.     

No carry over of unmetabolised deoxynivalenol in milk of dairy cows fed high concentrate proportions

To examine the carry over of deoxynivalenol (DON) and its metabolite de-epoxy DON (DOM-1) in milk, lactating German Holstein cows (n = 13) were fed an isoenergetic total mixed ration in Period 1 with 50% concentrates and 5.3 mg DON/kg dry matter (DM) over 11 wk and were compared with control cows (n = 14). In Period 2 (18 wk), an elevated concentrate proportion was compared to a low concentrate ration by dividing the cows into four Groups (n = 8): Control-30 (30% concentrates), Myco-30 (30% concentrates, 4.4 mg DON/kg DM), Control-60 (60% concentrates) and Myco-60 (60% concentrates, 4.6 mg DON/kg DM). Taken both periods together, no unmetabolised DON was detected in milk samples using the HPLC-UV method. DOM-1 concentrations ranged between below the LOD and 3.2 microg/kg milk in mycotoxin fed cows, while control cows did not excrete any measurable amounts of DOM-1. Regarding the concentrate effects, the carry over of DON as DOM-1 in milk was negligible (between 0.0001 and 0.0011) but significantly higher in Group Myco-30 than in Group Myco-60. This effect may result from an altered bioavailability of DON from maize silage which made up a higher proportion of the daily ration.     

动物性食品中三聚氰胺的残留及危害

三聚氰胺陆续在饲料和乳与乳制品中被检出,引起了公众对三聚氰胺的密切关注。为进一步了解三聚氰胺,就三聚氰胺在动物性食品中的污染来源、危害及其检测方法进行了阐述。     

高分辨质谱定性筛查牛奶和奶粉中兽药残留

目的 建立高分辨质谱定性筛查牛奶和奶粉中兽药残留的高通量方法。方法 样品经乙腈、QuEChERS盐包提取, 采取改良的3种不同方式[QuChERS、高分辨质谱(high resolution mass spectrometry, EMR)、固相萃取(solid phase extraction, SPE)]净化提取液, 用液相色谱联用高分辨质谱(liquid chromatography-high resolution mass spectrometry, LC-HRMS)筛查了牛奶和奶粉中138种兽药残留, 建立兽药信息数据库, 并用截断值(Vcut-off, 判断阳性和阴性样品的临界值)作为评估筛查方法的指标。结果 改良的QuChERS可以获得更高的回收率, 当截断值(Vcut-off)设定为0.2时, 在2种加标水平下, 有109种兽药通过了筛查方法验证的要求, 假阳性和假阴性概率均低于5%。结论 此方法适用于牛奶和奶粉中多兽药残留的定性筛查, 一针进样可以得到109种兽药残留的筛查信息, 方法假阳性和假阴性概率在规定的目标物浓度下都低于5%。     

酶联免疫法测定食品和饲料中的黄曲霉毒素

本实验应用酶联免疫方法对食品和饲料中的黄曲霉毒素进行测定,奶粉中黄曲霉毒素M1的多次重复测定的结果的变异系数小于12%,回收率接近90%。说明本试剂盒测定结果比较精确,重现性较好。食品辅料及饲料中的黄曲霉毒素B1的测定结果的变异系数小于15%,说明实验结果的重现性较好。     

酶联免疫法测定食品和饲料中的黄曲霉毒素

本实验应用酶联免疫方法对食品和饲料中的黄曲霉毒素进行测定，奶粉中黄曲霉毒素M1的多次重复测定的结果的变异系数小于12％，回收率接近90％。说明本试剂盒测定结果比较精确，重现性较好。食品辅料及饲料中的黄曲霉毒素B1的测定结果的变异系数小于15％。说明实验结果的重现性较好。     

Effects of caseinate, whey and milk powders on the texture and microstructure of emulsified chicken meat batters

The effects of adding dry caseinate, whole milk, skim milk, regular, and modified whey protein powders, at a level of 2 g/100 g, to meat batters were studied. All dairy additives, except for the regular whey, significantly reduced cook loss (30-50% reduction). Caseinate and modified whey formed distinct dairy protein gel regions within the meat batters, as revealed by light microscopy. Both also contributed more to enhancing the textural properties of the meat batters compared to the other dairy proteins; i.e., increasing texture profile analysis fracturability, and hardness, respectively. Overall, the most cost-effective ingredient appeared to be the modified whey, which also provided the best moisture retention.     

The use of carbon dioxide in the processing and packaging of milk and dairy products: A review

The upswing in consumer demand for fresh and high quality preservative‐free foods has led to the development of modified atmosphere packaging (MAP). Increasingly, MAP is being used with high carbon dioxide (CO₂) concentration as well as CO₂/N₂ gas mixes. Modified atmosphere packaging or ‘gas flushing’ as it is also known is an increasingly popular technique used to extend the shelf life (both quality and safety) of a number of dairy products. Carbon dioxide is an active constituent of MAP, naturally present in freshly drawn raw milk. Addition of CO₂ to raw milk or flushing the package headspace has proved to be a simple and cost‐effective method, depending upon the initial microbiological quality of the food product. Carbon dioxide addition through MAP or direct injection as an economically affordable shelf life extension strategy is used commercially worldwide for some dairy products. The development of food packaging machines with integrated gas flushing capabilities and the supply of ‘food grade’ gases allow dairy foods manufacturers to enhance the quality of their products. This review presents a broad spectrum of current research and the current trends with respect to CO₂ as a natural microbial hurdle with special focus on its precise mechanism and its role in quality improvement of dairy products.