HPLC Determination of Carotenoids in Fruits and Vegetables in the United States

A study was conducted to determine alpha- and beta-carotene and beta-cryptoxanthin in twenty-two fruits and vegetables. Foods were obtained from wholesale distributors from five locations throughout the United States (Los Angeles, Dallas, Chicago, Miami, and Boston) three times during a year (November, March, and July). Mean vitamin A activity in retinol equivalents (RE) of each food along with average values for the individual carotenoids (μg/100g) are given. beta-Carotene was the most prevalent carotenoid. Carrots, beet greens, spinach, swiss chard and sweet potatoes had the most vitamin A activity. Analysis of variance indicated that there were no significant differences among either locations or time of analysis. A comparison was made between the new values and the ones listed in USDA Handbook No. 8 and revised Handbook No. 8–9. There were differences between the old and new values in 14 of the 22 fruits and vegetables analyzed.     

Interaction between milk yield of Holstein cows in Mexico and the United States.

Genotype by environment interaction for milk yield was investigated by analyzing 55,162 mature equivalent, first lactation records of daughters from 1339 Holstein sires in Mexico and 499,401 daughters from 663 Holstein sires in the northeastern US. There were 474 US sires in common. Herd-year standard deviation was used to define non-overlapping high (> or = 1600 kg) and low (< or = 1300 kg) Mexican environments and a low (< or = 1025 kg) US environment. Variance components across Mexican environments were about 40% less than those of the US environment. Genetic correlation coefficients between milk yield in various Mexican environments and all US environments ranged from 0.60 to 0.71 and were different from unity (P < 0.001). Genetic correlation coefficients with low environment in the US ranged between 0.69 and 0.93; the largest correlation was between the low US and high Mexico environments. Both reductions in the size of genetic variance in Mexican environments relative to the US and genetic correlation coefficients less than unity were indicative of genotype by environment interaction. A significant rank change in estimated breeding values (EBV) of sires in Mexican environments relative to the US was another indicator of genotype of EBV of a sire estimated from daughters performances in low and high environments in Mexico were 0.46 and 0.62 against EBV of sires estimated from all data in the US. Against EBV estimated from the low environment in the US they were 0.57 and 0.83. The US low environment was a better predictor of performance in Mexican environments.     

Ascorbic Acid and Vitamin A Activity in Selected Vegetables from Different Geographical Areas of the United States

Reduced ascorbic acid (RAA) and Vitamin A (carotenoid) contents of six vegetables obtained from six cities in the United States at two seasons of the year were determined. Mean RAA content (mg/100g) of cabbage was 45.2, carrots 7.8, celery 6.0, corn 6.5, onions 8.4, and tomatoes 15.3. Vitamin C in cooked cabbage was 22.1, corn 6.2, and onions 5.7 mg/100g. Mean vitamin A activity (I.U.) of carrots was 15,228, cabbage 114, celery 133, corn 219, and tomatoes 750. In cooked cabbage and corn, vitamin A content was 89 and 217 I.U., respectively. The RAA and vitamin A content of vegetables from the six geographical areas varied significantly. Vitamin concentrations were generally lower than tabulated values. Retention of RAA in cooked cabbage was 52%; in onions, 58%; and in corn, 98%. Vitamin A retention in cooked cabbage was 82%, and in cooked corn was 98%.     

不同香烟烟雾对果疏中VC含量的影响

通过碘量法测定不同品牌香烟、不同的烟量对烟熏处理前后果蔬中维生素c含量的影响。试验结果表明,香烟对果蔬中维生素c破坏作用明显,低档香烟产生的烟雾对维生素C的破坏更大,维生素c含量高的水果可以有效抵抗香烟对维生素C的破坏。     

蔬菜中有机磷、有机氯农药残留量分析

分别采用电子俘获检测器(ECD)和火焰光度检测器(FPD)对常见的已禁用的几种农药进行有机氯和有机磷的气相色谱分析.试验结果显示,大部分样品未检出农药残留,已检出的样品没有超过国家限量标准,说明这些蔬菜没有使用这几种农药或对这几种农药采用科学合理的使用方法,没有滥用的现象.     

烹食过程对蔬菜中五种农药残留的动态影响

利用色谱分析法研究白菜和菜豆中克百威、甲胺磷、氧乐果、PP-DDT和氰戊菊酯等5种农药在洗涤和烹饪处理后残留量的动态变化情况,为农药残留风险分析与限量标准制订提供参考。结果表明,洗涤处理后农药残留去除率在8.0%—77.7%之间,清水洗涤效果最差;不同烹饪方式的去除效果差距明显,炸制处理最高达94.1%,而蒸制处理仅为48.3%;白菜样品的洗涤处理效果好于菜豆,烹饪处理效果则相反;克百威、甲胺磷和氰戊菊酯的洗涤处理效果较好,而氧乐果的煮制处理去除率最高,PP-DDT在其它烹饪方式处理后去除率较高。     

四川泡菜微生态分布及其与盐度、酸度的关系

以眉山、成都两个地区的传统发酵泡菜水和两个泡菜生产企业的盐渍水为研究对象,对所有样品的pH、酸度、盐度及其微生态进行了测定与分析。结果显示:(1)样品的食盐含量对微生物影响很大,而微生物的数量又与样品pH、酸度密切相关。(2)传统发酵泡菜水样品中的乳杆菌、乳球菌、明串珠菌的含量均较高,有的甚至达到108CFU/mL;大部分传统发酵泡菜水中的酵母菌含量较高,在102～106CFU/mL之间;少量泡菜水中存在醋酸菌。企业盐渍菜样品中菌落总数在102～105CFU/mL之间,乳酸菌数和酵母菌数均在10～105CFU/mL之间。(3)另外,少数样品受到霉菌污染,大多数的传统发酵泡菜样品受到了假单胞菌或芽孢杆菌的污染。     

京津两地蔬菜防腐剂、保鲜剂和添加剂使用情况的调查研究

目的：了解北京和天津地区夏季蔬菜产、储、运环节中三剂（防腐剂、保鲜剂和添加剂）的使用情况。方法：2012年夏季（7、8月份）对京津两地主要蔬菜生产基地的种植户和蔬菜批发市场的销售商进行现场问询调查并随机购买蔬菜,7月份取样蔬菜有10种,8月份有17种,取样后带回实验室进行检测,分析三剂的使用情况。结果：问卷调查结果显示,京津两地蔬菜生产基地和批发市场所抽查的蔬菜没有使用三剂对蔬菜进行贮藏保鲜的情况,但分析检测发现,7、8月份使用甲醛对蔬菜进行防腐保鲜的比例分别为93．3％、89．2％,而且在蔬菜批发市场还发现有使用硫磺对胡萝卜、生姜、蒜熏色处理的现象以及使用含有仲丁胺的冰块对蔬菜贮藏保鲜,此外某些蔬菜多茵灵、哒螨灵、霜酶威残留超标较严重。结论：北京、天津两地主要蔬菜批发市场以及蔬菜生产基地存在添加使用防腐剂、保鲜剂和添加剂的情况,应引起种植者、销售者和有关部门的重视。     

子午岭林区常见野生蔬菜硝酸盐、亚硝酸盐及维生素C含量的测定

测定了子午岭林区常见19种野生蔬菜中的硝酸盐、亚硝酸盐和维生素C的含量,比较蔬菜中硝酸盐分级评价标准和我国制定的无公害蔬菜亚硝酸盐限量标准及维生素C的含量发现,香椿硝酸盐含量处于安全水平,但亚硝酸盐含量高于我国制定的无公害蔬菜亚硝酸盐的限量标准,且维生素C含量小于50 mg/100g,不属于无公害蔬菜的范畴,建议少量食用或经过特殊处理后再食用;其余17种野生蔬菜均属于安全无公害蔬菜,且维生素C的含量高,可放心食用.     

Effect of an intramammary lipopolysaccharide challenge on the hindgut microbial composition and fermentation of dairy cattle experiencing intermittent subacute ruminal acidosis

Feeding grain-rich diets often results in subacute ruminal acidosis (SARA), a condition associated with ruminal dysbiosis and systemic inflammation. Yet, the effect of SARA on hindgut microbiota, and whether this condition is aggravated by exogenous immune stimuli, is less understood. Therefore, the aims of this study were to determine the effects of an intermittent high-grain SARA model on the hindgut microbial community, and to evaluate whether the effects of SARA on the fecal microbiome and fermentation were further affected by an intramammary lipopolysaccharide (LPS) challenge. A total of 18 early-lactating Simmental cows were divided into 3 groups (n = 6); 2 were fed a SARA-inducing feeding regimen (60% concentrate), 1 was fed a control (CON) diet (40% concentrate). On d 30, 1 SARA group (SARA-LPS) and the CON group (CON-LPS) were intramammarily challenged with a single dose of 50 µg of LPS from Escherichia coli O26:B6, whereas the remaining 6 SARA cows (SARA-PLA) received a placebo. Using a longitudinal randomized controlled design, with grouping according to parity and days in milk), statistical analysis was performed with baseline measurements used as a covariate in a mixed model procedure. The SARA-inducing feeding challenge resulted in decreased fecal pH and increased butyrate as a proportion of total short-chain fatty acids in the feces. On d 30, SARA-challenged cows had decreased fecal diversity as shown by the Shannon and Chao1 indices and a decrease in the relative abundance of Euryarchaeota and cellulolytic genera, and numerical increases in the relative abundance of several Firmicutes associated with starch and secondary fermentation. The LPS challenge did not affect the fecal pH and short-chain fatty acids, but increased the Chao1 richness index in an interaction with the SARA challenge, and affected the relative abundance of Verrucomicrobia (1.13%), Actinobacteria (0.19%), and Spirochaetes (0.002%), suggesting an effect on the microbial ecology of the hindgut during SARA conditions. In conclusion, the SARA-inducing feeding regimen promoted important microbial changes at d 30, including reduced diversity and evenness compared with CON, whereas the external LPS challenge led to changes in the microbial community without affecting fecal fermentation properties.     

美国大豆生产分析及展望

大豆作为美国的主要农作物之一,在美国农业经济和国际农产品贸易中占有重要地位。文章从美国大豆生产概况入手,分析了美国大豆种植面积、单产和总产量的变化以及对大豆的补贴情况,总结了美国大豆总产量、总产值以及价格等的变化趋势,介绍了近期气候条件等因素对美国大豆生产的影响;依据气候条件及单产等因素,估算了2011年美国大豆单产和总产;并对未来一段时期美国大豆的生产前景进行展望。     

Effect of modified atmosphere packaging on the microbial development and visible shelf life of a mayonnaise-based vegetable salad

The effect of a modified atmosphere of 20% carbon dioxide, 80% nitrogen, on the microbial development and visual shelf life of a mayonnaise-based vegetable salad is reported. The modified atmosphere delayed the spoilage of the salad at all three chosen storage temperatures. The principal organisms causing spoilage of the salads were yeasts, those spoiling the modified atmosphere packs having a fermentative ability. Modified atmosphere packaging of the vegetable salad would allow the manufacturer to increase the shelf life of the product from 40 to 54 days at 4°C storage, 12 to 22 days at 10°C storage, and 5 to 12 days at 15°C storage.     

Selection response for milk production in conventional production systems in Mexico, using genetic evaluations of Holstein sires from Canada and the United States

Polynomial regression models of the first, second, and third order were used to fit milk production deviations of daughters in Mexico on Canadian and US predicted transmitting ability values for 305-d mature-equivalent milk production (kg). For the pairs Canada-Mexico and Mexico-United States, 40 and 73 bulls with a minimum reliability of 0.75 were analyzed, respectively. Genetic correlations between pairs of countries were also estimated. The parameters were evaluated for all data, and for sires grouped according to the mean of the average phenotypic milk production (high and low) of their daughters’ herd mates. Quadratic and cubic effects were not significant in any analysis. From linear regression models, slopes of Mexican daughter deviations on US and Canadian predicted transmitting abilities were 1.01 and 0.93, respectively. Slopes were greater but intercepts were smaller for the high versus low level of production of the sires’ herd mates in Mexico. A greater difference between the genetic correlations was found for the high versus low environmental level than for the low level (0.79 vs. 0.70) for Mexico-US data compared with Canada-Mexico data (0.81 vs. 0.78). Genetic correlations between Mexico and the United States (0.74), and between Mexico and Canada (0.77), were smaller than the genetic correlation between the same Canadian and US sires (0.92), suggesting the presence of a moderate degree of genotype-environment interaction for milk production between Canada and the United States, and Mexico.     

Management of preweaned bull calves on dairy operations in the United States

Many calves born on dairy farms are male, but little research to date has focused on the management of these calves. The objective of this study was to survey management practices of preweaned dairy bull calves and compare these practices with those used for heifer calves on the same operations. This study was conducted as part of the USDA National Animal Health Monitoring System Dairy 2014 study and included a sample of 42 operations from 10 states. On average, 2.4% of bull calves died before leaving the operation, with most operations selling bull calves before weaning (97.6%). Bull calves left the operation at an average age of 7.6 d (median = 4 d). Producers reported that 96.3% of bull calves received colostrum. Of bulls that were fed colostrum, the vast majority (95.4%) were hand-fed; the remaining calves received colostrum via a combination of hand-feeding and suckling (3.1%) or by suckling only (1.5%). In contrast, all heifer calves on those operations were only hand-fed colostrum. On average, bull calves received 3.1 L of colostrum at their first feeding at 4.3 h after birth compared with 2.9 L at 2.9 h after birth for heifer calves. In the first 24 h, bull and heifer calves received 4.8 and 5.5 L of colostrum, respectively. Only 21.4% of operations dehorned bull calves; in comparison, heifer calves were dehorned on 90.5% of operations. Few operations used analgesics or anesthetics when dehorning bull calves, whereas 28.9% of operations used anesthetics or analgesics when dehorning heifer calves. Overall, 27.8% of operations castrated bull calves. Of the operations that did castrate bulls, 70.0% used a band at an average age of 6.3 wk; the remaining 30% of operations used a knife at 14.7 wk of age on average. Few operations used analgesics or anesthetics when castrating. These results illustrate differences in the care of bull and heifer calves and suggest the need to improve education regarding recommended colostrum feeding and pain management practices in all calves regardless of sex.     

Public perceptions of antibiotic use on dairy farms in the United States

There has been a global push for improved antimicrobial stewardship, including in animal agriculture, due to growing concerns about antimicrobial resistance. However, little is known about the general public's perceptions of antimicrobial use in animal agriculture. The aim of this study was to explore the US public's perceptions of antibiotic use in dairy farming and how these perceptions influence purchasing decisions. Data from the 2017 Cornell National Social Survey developed in collaboration with the Cornell Survey Research Institute were used to assess the public's perceptions. The Survey Research Institute of Cornell University (Ithaca, NY) administered the survey by telephone to a random sample of 1,000 adults in the continental United States. The survey collected information about perceptions of threat to human health posed by antibiotic use in cows on dairy farms and willingness to pay more for milk from cows raised without antibiotics, as well as several presumed explanatory variables, including respondents' knowledge of antibiotics, beliefs regarding cattle treatment in dairy farming, and 18 sociodemographic characteristics. Data were analyzed using logistic regression. Among respondents, 90.7% (n = 892/983) reported that antibiotic use on dairy farms posed some level of threat to human health and 71.5% (n = 580/811) indicated they would be willing to pay more for milk produced from cows raised without antibiotics. Respondents who believed that antibiotic use in dairy farming posed a moderate to high threat to human health were more likely to be female and report willingness to pay more for milk or not purchase milk. Additionally, consumers' willingness to pay more for milk from cattle raised without antibiotics was associated with the belief that antibiotic use posed some threat to human health, the belief that cows are treated better on organic dairy farms, an annual household income of $50,000 or greater, being born outside the United States, having a liberal social ideology, and being currently or formerly married. These results suggest that the general public's decisions as consumers of dairy products are associated with demographic factors in addition to perceptions of antibiotic use and cattle treatment in dairy farming. The rationale behind such perceptions should be further explored to facilitate consumers' informed decision making about antibiotic use in agriculture, links to cattle treatment, and associated willingness-to-pay attitudes.     

美国国家营养监测计划及对我国的启示

公众的营养与健康状况是反映一个国家社会与经济发展、卫生健康水平和人口素质的重要指标,是国家制定营养相关政策的重要依据,因此,对全国居民展开营养监测必不可少。本文分析了美国相对完善的国家营养监测计划、对比了我国营养监测的现状,认为美国的营养监测计划在体制、执行和财政投入等方面对完善我国营养监测体系具有重要的借鉴价值。我国应尽快制定和完善适合本国国情的国家营养监测计划,提高其全面性、严密性、时效性及针对性,及时采取干预措施,指导人群健康膳食,保护公众的健康和安全。     

Reproductive status of Holstein and Jersey cows in the United States

Reproductive information since 1995 from the USDA national dairy database was used to calculate yearly Holstein and Jersey means for days to first breeding after calving (DFB), 70-d nonreturn rate, conception rate (CR), number of breedings per lactation (NB), interval between first and last breedings during the lactation, days to last breeding after calving (DLB), pregnancy rate (PR), calving interval (CI), and interval between consecutive breedings. Data were from nearly 20 million breedings during >8 million lactations of >5 million cows in >23,000 herds. Means were also calculated for some traits by parity and breeding number for both breeds and by geographical region and synchronization status for Holsteins. The DFB declined for Holsteins from 92 d in 1996 to 85 d in 2007; the trend in yearly differences was not as consistent for Jerseys. First- and all-breeding 70-d nonreturn rate declined 5 to 9 percentage units over time. First- and all-breeding CR declined 2 to 4 percentage units. The DFB were longer for later parities of Holsteins than for early parities. Second- and third-breeding CR were sometimes 1 to 2 percentage units above first-breeding CR for Holsteins but lower (1 to 7 percentage units) for Jerseys. The CR within breeding number declined across parities for both breeds. The NB increased by 0.3 to 0.4 breedings over time but remained constant (2.5 or 2.6 breedings) across parities for Holsteins and increased (from 2.2 to 2.4 breedings) for Jerseys. Holstein DFB were fewest in the Northwest (78 d) and greatest in the Mountain region (92 d). Regional CR was highest for the Northeast and Southwest (33%) and lowest for the Southeast (26%); NB was fewest for the Northeast (2.3) and greatest for the Southeast (2.7). Mean DLB was fewest for the Southwest (127 d) and greatest for the Mountain region (157 d); CI was shortest for the Southwest (406 d) and longest for the Mideast (434 d). Mean PR was highest for the Southwest (28.3%) and lowest for the Mideast and Southeast (22.2%). Use of timed artificial insemination following synchronized estrus appears to have reduced DFB, lowered CR, and increased NB while reducing DLB and CI. However, synchronized breeding was not a primary cause of Holstein regional differences for reproductive traits. Since 2002, phenotypic performance for CR, DLB, and CI as well as genetic merit for daughter PR have stopped their historical declines and started to improve.     

Influence of Asian and Western United states agricultural areas and fires on the atmospheric transport of pesticides in the Western United States

Historic and current use pesticides (HUPs and CUPs), with respect to use in the United States and Canada, were identified in trans-Pacific and regional air masses at Mt. Bachelor Observatory (MBO), a remote high elevation mountain in Oregon's Cascade Range located in the United States, during the sampling period of April 2004 to May 2006 (n = 69), including NASA's INTEX-B campaign (spring 2006). Elevated hexachlorobenzene (HCB) and alpha-hexachlorocyclohexane (alpha-HCH) concentrations were measured during trans-Pacific atmospheric transport events at MBO, suggesting that Asia is an important source region for these HUPs. Regional atmospheric transport events at MBO resulted in elevated dacthal, endosulfan, metribuzin, triallate, trifluralin, and chlorpyrifos concentrations, with episodic increases in concentration during some spring application periods, suggesting that the Western U.S. is a significant source region for these CUPs. Endosulfan I, gamma-HCH, and dacthal concentrations were significantly positively correlated (p-value < 0.05) with increased air mass time in Western U.S. agricultural areas. Elevated gamma-HCH concentrations were measured at MBO during both trans-Pacific and regional atmospheric transport events, including regional fire events. In addition to gamma-HCH, elevated sigmachlordane, alpha-HCH, HCB, and trifluralin concentrations were associated with fires in Western North America due to revolatilization of these pesticides from soils and vegetation. Trans-chlordane/cis-chlordane and alpha-HCH/gamma-HCH ratios were calculated and may be used to distinguish between free tropospheric and regional and/or Asian air masses.     

Influence of Asian and Western United States urban areas and fires on the atmospheric transport of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and fluorotelomer alcohols in the Western United States

Atmospheric measurements of semivolatile organic compounds (SOCs) were made at Mt Bachelor Observatory (MBO), located in Oregon's Cascade Range, to understand the trans-Pacific and regional transport of SOCs from urban areas. High volume air sampling (approximately 644 m3 for 24 h periods) of both the gas and particulate phases was conducted from April 19, 2004 to May 13, 2006 (n = 69); including NASA's INTEX-B campaign in spring 2006 (n = 34 of 69). Air mass back trajectories were calculated and were used to calculate source region impact factors (SRIFs), the percentage of time the sampled air mass resided in a given source region. Particulate-phase polycyclic aromatic hydrocarbon (PAH) concentrations at MBO increased with the percentage of air mass time in Asia and, in conjunction with other data, provided strong evidence that particulate-phase PAHs are emitted from Asia and undergo trans-Pacific atmospheric transport to North America. Gas-phase PAH and fluorotelomer alcohol (FTOH) concentrations significantly increased with the percentage of air mass time in California's urban areas, whereas retene and polychlorinated biphenyl (PCB) concentrations increased with the percentage of air mass time in Oregon and during regional fire events. In addition, sigma(gas-phase) PAH, retene, and levoglucosan concentrations were significantly correlated (p-value < 0.001) with sigma(PCB) concentrations, suggesting that increased atmospheric PCB concentrations were associated with fires due to the volatilization of stored PCBs from soil and vegetation.