Antibiotic residues in milk from small dairy farms in rural Peru

The use of antibiotics in livestock can pose a public health threat, especially if antibiotic residues remain in the food product. Understanding how often and why farmers sell products with antibiotic residues is critical to improving the quality of these products. To understand how often milk with antibiotic residues is sold on small farms in a major dairy-producing region of Peru and identify factors associated with selling milk with antibiotic residues, we tested milk samples for antibiotic residues from every provider on three routes of commercial milk companies and from bulk tanks of farmers currently treating cows with antibiotics. We also asked farmers if they sold milk from treated cows and examined factors associated with the tendency to do so. The prevalence of milk contamination with antibiotic residues on commercial routes was low (0–4.2%); however, 33/36 farmers treating their animals with antibiotics sold milk that tested positive for antibiotic residues. The self-reported sale of milk from treated cows had a sensitivity, specificity, and positive and negative predictive values of 75.8%, 100%, 100% and 27.2%, respectively (with testing of milk for residues as the gold standard). Finally, 69/156 randomly selected farmers reported selling milk from treated cows, and farmers’ knowledge of antibiotics and the milk purchaser were significantly associated with a farmer’s tendency to report doing so. Educating farmers on the risks associated with antibiotics and enforcement of penalties for selling contaminated milk by milk companies are needed to improve milk quality.     

Starch and dextrose at 2 levels of rumen-degradable protein in iso-nitrogenous diets: Effects on lactation performance,ruminal measurements,methane emission,digestibility, and nitrogen balance of dairy cows

Our objectives were to determine the effects of readily rumen-available carbohydrate source (refined starch vs. dextrose), the level of rumen-degradable protein (RDP), and their interaction on lactation performance, ruminal measurements, enteric methane (CH₄) emission, nutrient digestibility, and nitrogen (N) balance in lactating dairy cows. Eighteen mid-lactation multiparous Holstein cows were used in this split-plot study. The main plots were created by randomly assigning 9 cows to diets of 11 or 9% RDP obtained by altering the percentage of soybean meal, expeller soybean meal, and blood meal in the diet. All diets included 16.4% crude protein. In the subplots, the effects of 0:10, 5:5, and 10:0 refined starch:dextrose ratio (% of dietary dry matter) were determined in three 3 × 3 Latin squares by randomly assigning the 9 cows in each RDP level into squares. Each period lasted 4 wk, with the last 2 wk allotted for sample collection. Carbohydrate source × RDP level interaction tended to influence dry matter intake (DMI), the concentration of urinary N, and urinary urea-N. Replacing refined starch with dextrose increased DMI, the molar percentage of ruminal butyrate and valerate, daily CH₄ production (g/d), and fecal N and decreased the molar percentage of ruminal branched-chain volatile fatty acids, feed efficiency (fat- and protein-corrected milk/DMI), and N use efficiency (milk N/intake N) but did not influence nutrient digestibility. Enteric CH₄ production was negatively related to the molar percentage of ruminal propionate but positively related to the molar percentage of ruminal butyrate. Treatments did not influence milk production responses, but cows fed 9% RDP diets had lower ruminal ammonia concentration (7.2 vs. 12.3 mg/dL) and tended to excrete less urinary purine derivatives (428 vs. 493 mmol/d) compared with cows fed 11% RDP diets, suggesting lower ruminal synthesis of microbial protein. Reducing the level of RDP in iso-nitrogenous diets had no effect on nutrient apparent total-tract digestibility, manure excretion and composition, N balance, and CH₄ production. In this study, treatments did not affect yield (20.0 g of CH₄/kg of DMI) or intensity (13.1 g of CH₄/kg of fat- and protein-corrected milk), but methane production (g of CH₄/d) was 7.0% lower and N use efficiency (conversion of intake N into milk protein) was 7.8% higher for cows fed a diet of 28.1% starch and 4.6% water-soluble carbohydrate compared with diets with lower starch and higher water-soluble carbohydrate contents.     

米糠的高效利用研究

我国是稻米生产、加工、消费大国,而米糠是稻米加工的副产物,平均加工出康率为7%。米糠中含有蛋白质、脂肪、纤维素、维生素和多种生物活性功能因子。对米糠进行深度加工,全面、高效地利用这一资源具有现实和长远的重要意义。     

蛋壳资源综合利用现状与对策

综述了蛋壳资源现状及研究进展,阐述了蛋壳资源综合利用过程中存在的问题和解决办法,为蛋品深加工及蛋壳资源的开发利用提供新的思路。     

新型功能高分子材料的研究与应用

目的：系统地介绍了几类新一代功能高分子材料，旨在为进一步的研究，开发与应用提供有价值的参考。方法：在分析现有功能高分子材料结构特征的基础上，着重阐述了几种新一代功能高分子材料的性能特点，功能原理及发展动态，结果：高分子材料在结构上的复杂性和多相关性一，使其可进行单一或多种结构的综合利用，最大程度地满足其他高新技术要求材料技术所提供的各种功能。结论：新世纪材料技术发展的主流将是分子纳米材料及其相关学科的融合。     

浅谈酒用纸制包装品的检测

介绍了纸制包装品的质量要求,以及酒用纸制包装品的检测和我们在实际工作中的经验.     

Comparing tobacco use among incoming recruits and military personnel on active duty in the United States

OBJECTIVE—To compare the tobacco use profile of recruits with that of military personnel on active duty to determine whether the military environment in some way induces service members to initiate tobacco use.
DESIGN AND SETTING—Cross-sectional survey of United States armed forces active duty and recruit personnel in 1994-95.
SUBJECTS—2711 military recruits and 4603 military personnel on active duty.
MAIN OUTCOME MEASURES—Comparative cigarette smoking and smokeless tobacco use prevalence between recruits and personnel on active duty controlling for age, sex, and race. Impact of demographic factors on the odds of smoking or using smokeless tobacco.
RESULTS—Increases in tobacco use in American military personnel occurred exclusively in men. The highest tobacco use resided with white men on active duty (43% cigarette smoking; 24% smokeless tobacco use) and represents a doubling of tobacco use seen among white male recruits. Among non-white men, tobacco use increased 2-4 times between recruits and personnel on active duty.
CONCLUSIONS—Efforts to reduce tobacco use by American military personnel on active duty should focus more on discouraging the initiation of tobacco use.


Keywords: tobacco use; military personnel; United States     

浅析婴幼儿食品中食品添加剂的使用管理问题

婴幼儿食品安全是食品安全工作的重点领域。目前,婴幼儿食品中违规使用非食用物质和滥用食品添加剂的现象依然存在。为建立合理的添加原则,保障产品的质量,减少因滥用食品添加剂所致的健康危害,国际组织和我国均制定了相应的法规和标准。本文全面系统地介绍了国际和国内涉及婴幼儿食品中食品添加剂使用的相关法规和标准概况,并对我国婴幼儿食品中食品添加剂的使用安全问题进行了分析,旨在对我国婴幼儿食品中食品添加剂的使用管理提供参考和借鉴。     

纳米复合阻燃材料的制备方法及其在纺织上的应用

纳米复合阻燃材料是将纳米技术应用于阻燃材料而制得的一种新型功能复合材料．概述了纳米复合阻燃材料的制备方法及其在纺织领域的应用，并对其中的PLS纳米复合阻燃材料的阻燃机理、结构和阻燃性能的表征进行了评述．     

氮肥运筹方式对油菜产量、氮肥利用率及氮素淋失的影响

通过盆栽模拟试验研究了不同氮肥运筹方式对油菜产量、氮肥利用率、氮素淋失及氮素平衡的影响。试验设5个处理：不施氮肥（CK）,氮肥全部基施（TJ）,氮肥60%基施、40%做越冬肥追施（TJD）,氮肥60%基施、40%做薹肥追施（TJT）,氮肥60%基施、20%做越冬肥、20%做薹肥追施（TJDT）。研究结果表明,氮肥分期施用可明显增加油菜产量,提高氮肥利用率,其中以TJDT处理效果最佳,与TJ处理相比,TJDT处理的产量、氮肥农学利用率及表观利用率分别提高了17.6%、2.1kg·kg^-1氮和4.9%。同时,TJDT处理的氮素淋失量也最小。氮素平衡计算结果表明,不同时期追施氮肥对氮素平衡影响不大,但是均比氮肥集中做基肥施用（TJ）的表观损失明显减小。尽管油菜收获后,各施氮处理土壤氮素均有盈余,但分期施肥盈余量明显高于TJ。研究表明在油菜生产中,氮肥分期施用既能提高油菜籽的产量和氮肥的利用效率,又可获得较好的环境效应。