Aflatoxin in corn

Low incidence and levels of aflatoxin were identified in corn of all grades grown in the Midwest in 1964, 1965, and 1967. Later surveys indicate that corn grown in southern regions is subject to invasion byAspergillus flavus and subsequent aflatoxin formation. This mycotoxin is formed either in the field or in storage. In the field, such factors as insect damage and weather conditions probably influence aflatoxin formation. In storage, temperatures must be above 25 C and moisture levels above 16% if toxin is to form. Aflatoxin formed in a hot spot in stored corn in the Midwest when temperatures rose early in the summer and when the grain became wet because of leaks in the storage building. Analytical methods to detect and determine aflatoxin fall into three categories: presumptive tests indicating the presence ofA. flavus and the possible occurrence of aflatoxin, rapid screening tests establishing the presence or absence of the toxin, and quantitative procedures determining toxin levels. Detoxification methods being studied include ammoniation and roasting. Ammoniated corn is being fed domestic animals to determine whether it has adverse effects and whether toxic compounds are transmitted in animal tissues.     

Aflatoxin in pecans: Problems and solutions

The aflatoxin contamination potential in pecans has been clearly demonstrated in the literature. No definitive study has been published indicating the extent of aflatoxin contamination in pecans. Good manufacturing practices can be maintained in culture, drying, sizing, storing, and processing which should reduce the possibility of mold growth or aflatoxin production. Sampling of pecans for aflatoxin analysis would be costly due to the great number of pecan sizes and grades as well as to the high cost of pecans. Surveillance costs could be minimized by incorporating chopping with subsampling.     

Aflatoxin content of peanut hulls

The degree of aflatoxin contamination in peanut hulls was determined by analyzing inoculated hand-shelled hulls and hulls from peanuts known to contain aflatoxin. Hulls adjusted to 20% moisture, inoculated withAspergillus flavus, and incubated 7 days at 25 C supported growth ofA. flavus but not aflatoxin production. Peanuts from 20 selected Segregation III (visibleA. flavus) lots contained 13–353 ppb of aflatoxin. The machine-shelled hulls from these lots were analyzed and 3 lots contained no detectable aflatoxin, 13 lots contained 4–88 ppb and 4 lots contained >116 ppb. Aflatoxin concentrations of 53–87 ppb were detected in hulls when peanuts containing relatively high levels of aflatoxin (up to 26.8 ppm in damaged kernels) were carefully machine-shelled. Hulls from the same samples obtained by hand-shelling contained no detectable aflatoxin. When machine-shelled hulls were screened through successively smaller screens, the aflatoxin concentration of the smallest fraction (<3.18 mm) was always highest and indicated that small peanut kernels and peanut parts in the hulls actually contained the aflatoxin. Separating hulls over a 4.76 mm round-hole screen appeared to provide a means of removal of most aflatoxin in peanut hulls. No aflatoxin was found in hulls from uncontaminated peanuts.     

Aflatoxin control program for Peanuts

Under provisions of a USDA Marketing Agreement, an aflatoxin control program for peanuts produced in the United States is administered by the Peanut Administrative Committee composed of peanut growers and shellers. Regulations of this committee contain provisions about the quality of peanuts acquired from farmers, storage of unshelled peanuts, aflatoxin testing, quality and disposition of processed lots, and indemnification of handlers for losses caused by lots which test over 25 parts-perbillion aflatoxin. Effects of the control program on aflatoxin concentrations in peanut products are discussed. Paper number 4978 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC 27607.     

食用油中黄曲霉毒素B1的污染调查

为了初步了解市售的食用油中黄曲霉毒素B1的污染状况,为食品安全监管提供科学依据。采用统计学方法随机抽取市场上食用油1103份,采用高效液相色谱法进行测定。检出不合格样品24份,不合格率为2.2%,含量范围为17.5~282.7μg/kg;其中花生油共248份,不合格数21份;玉米油共170份,不合格数为2份;调和油共123份,不合格数为1份;其余的样品均为合格样品,所有检出不合格样品中黄曲霉毒素B1的含量均≥10μg/kg。其中散装油不合格率(5.2%)是定型包装油不合格率(1.2%)的4.3倍。调查结果显示,市售的食用油存在一定程度的黄曲霉毒素B1污染,应做好一定的防范工作,有利于国家的监管。     

Aflatoxin distribution in fines and meats from decorticated cottonseed

Nine samples of fuzzy cottonseed potentially high in aflatoxin were separated into hulls, fines and meats. Assays for aflatoxin on triplicate 50-g portions from fines (small, dry particles of kernels) and meats from each of the nine samples indicated a marked concentration of toxin in the fines. On average, there was a 17-fold difference between the aflatoxin content of the fines and that of the meats; the average toxin level in fines was 4024 μg/kg and that in the meat samples was 232 μg/kg. These results indicate a potential for marked reduction in aflatoxin content of processed cottonseed meal by physical removal of fines from meats after dehulling and before processing of meats into oil and meal.     

Aflatoxin inactivation of undelinted cottonseed by ammoniation

The inactivation of aflatoxin in cottonseed products has been restricted principally to ammoniation of cottonseed meal. More recently, attention has been focused on the feasibility of ammoniating whole cottonseed as a feed for ruminants. Preliminary work is presented on treatment with gaseous ammonia of undelinted (fuzzy) cottonseed containing an average of 1,500 μg/kg total aflatoxins. These seed were treated with 4% anhydrous ammonia (w/w) for 30 min at temperatures ranging from 66 C to 82 C. The data obtained in this study indicate that inactivation of aflatoxins in undelinted whole cottonseed may be accomplished using processing conditions comparable to those proposed for cottonseed meal.     

Occurrence of Aflatoxin M1 in Dairy Products in Southern Italy

A screening survey of the presence of aflatoxin M₁ (AFM₁) was carried out on 265 samples of cheese made from cow, buffalo, goat, sheep, sheep-goat milk collected in the Apulia region (Southern Italy). Selected samples included unripened, medium and long-term ripened cheeses. AFM₁ was found in 16.6% of the analyzed samples. The highest positive incidence was for medium and long-term ripened cheeses, especially those made from sheep-goat milk, while buffalo cheeses tested consistently negative. Our results show that the level of contamination by AFM₁ in dairy products from Apulia Region are lower than in other Italian and European regions. Moreover, it is important to underline that a common European norm concerning the AFM₁ threshold limits for dairy products is still lacking.     

黄曲霉毒素的酶学检测方法及应用

黄曲霉毒素是由黄曲霉菌产生的一种次级代谢产物,对人和动物都有很大的伤害。黄曲霉毒素会通过被污染的谷物、粮食、饲料等以及通过用污染的饲料喂养动物而进入人体,从而对人畜产生致癌、致畸等危害,因此,准确地检测食品中的黄曲霉毒素含量具有重要的意义。本文论述了黄曲霉毒素的酶学检测方法,并就其应用进行讨论。     

The toxicity of pesticides for livestock

Conclusion In this discussion I have covered the relationship of toxicity to hazard, and I have argued that normally expected residues of pesticides on forage are practically never a hazard to livestock, but that some of the pesticides are stored in the tissues of livestock and excreted in their milk, creating a potential hazard to people. This hazard can be avoided by carefully following label instructions as to dosage and proper intervals which must occur between treatment and harvest of slaughter. I have indicated that chemical analyses are of virtually no value for diagnostic purposes. I have pointed out that all the toxicological information developed for a given compound can be utilized only if the manufacturer, formulator, and consumer contribute equally to safe, intelligent usage. The manufacturers and formulators must prepare the compounds in stable, readily usable form, and devise labels for the final product, which will clearly define the intended uses and limitations of the product. The consumer must read the label and adhere strictly to the suggestions found there. I believe that the rational use of pesticides in agriculture is essential if we are to maintain maximum productivity in the face of constantly shrinking farm and ranch land and an exploding population. I believe that these materials can be, and are being, used with complete safety to man and animals when label instructions are followed.     

Aflatoxin in freshly harvested 1979 georgia corn and formation after collection

In the crop year 1979, freshly harvested dent corn was coUected at maturity in 57 sets of 2 equivalent samples/set. One set was dried the day of collection in Georgia and the other set was shipped to Peoria in corrugated cardboard boxes before drying, The set that was not dried in Georgia was shelled and dried as soon as possible after arrival in Peoria to prevent further aflatoxin formation. Both sets of samples were analyzed randomly at the Northern Regional Research Center, Peoria. In 22 Peoria-dried samples, aflatoxin was detected in levels ranging from 2 to 449 ng/g total toxin but was not detected in the matching samples dried die same day of collection in Georgia. It took an average of 7 days to ship samples from Georgia. Of the 57 samples dried in Georgia, 63% were negative for aflatoxin; aflatoxin was below violative levels (>20 ng/g) in 82%; the average aflatoxin level in all samples was 36 ng/g. In the matching 57 samples dried in Peoria after shipment, aflatoxin was detected in all but 37%; aflatoxin was below violative levels in 70% of the samples; the average aflatoxin level in all samples that had been dried later was 78 ng/g. There was a significant increase in aflatoxin-positive samples associated with shipment prior to drying. These results indicate that aflatoxin formed during shipment of the 1979 freshly harvested corn samples from Georgia.     

欧洲综合处理畜禽粪尿的工艺技术

欧洲工业化养殖业的成功发展,使每年产生大量的畜禽粪便。近年来,许多欧洲国家政府积极资助对农场废物处理技术的研究开发,以达到保护环境、变废物为有利资源的目的。综合处理畜禽废物的生产工艺技术在欧洲已经逐渐流行起来,其特点是结合多种处理技术,主要适合于畜禽废物已引起严重污染的高密度养殖业地区。本文对欧洲具有一定代表性的综合处理畜禽废物工艺过程进行分析,以便我们了解欧洲综合处理畜禽废物工艺技术的特点、现状和发展趋势。     

胶体金免疫层析法测定巴旦木中的黄曲霉毒素B1

采用胶体金免疫层析法快速检测巴旦木中的黄曲霉毒素B1。巴旦木样品粉碎后,经提取,以胶体金免疫层析法对其进行黄曲霉毒素B1测定,并与酶联免疫吸附法进行比较。结果表明,当巴旦木中黄曲霉毒素含量超过国家限量标准（5μg／kg）,胶体金免疫层析法检测结果为阳性,说明该方法能够满足干果样品中黄曲霉毒素B1快速检测的要求。     

酶联免疫法对食用油中黄曲霉毒素B_1的检测

目的:建立一种对食用油中黄曲霉毒素B_1(Aflatoxin B1,AFB_1)的检测方法。方法:食用油样本经60%甲醇-水提取,再做1︰5稀释,通过酶联免疫吸附法(enzyme linked immunosorbent assay,ELISA)测定样本中AFB1。结果:阴性样品中AFB1的回收率分别为:92.5%、84.8%及86.3%;方法检出限为1μg/kg,与液相方法检测结果的相对标准偏差小于10%。结论:酶联免疫法对食用油中AFB1的测定结果与液相法比较符合率高,能够用于食用油中AFB1的快速、准确检测。     

ELISA法测定花生油中黄曲霉毒素B_1含量的不确定度分析

根据CNAS-GL06:2006《化学分析中不确定度的评估指南》中提供的方法,对ELISA法测定花生油中黄曲霉毒素B1含量过程中影响测定结果的因素进行分析,建立数学模型,对模型中的变量进行分解,确定影响每一变量的不确定度分量并进行计算,合成标准不确定度和扩展不确定度。花生油中黄曲霉毒素B1含量测定结果为(18.3±0.97)μg/kg,通过评定,影响含量测定的最主要不确定度分量为标准曲线的拟合。     

Contribution of livestock excreta to nutrient balances

Livestock excreta make an important contribution to soil nutrient inputs and in many developing countries are the only significant input. However, there is little quantitative information available on excreta, manure production, and application and this makes it difficult to obtain meaningful soil nutrient balances. A model has therefore been developed to calculate the excreta produced and manure recovered at national levels. Excretion rate coefficients are developed for six farm animal categories and using information on animal numbers and weights obtained from the FAO Internet database, excreta production is calculated for 195 countries and the World for 1996. In addition, time series results for the period 1961 to 1996 are presented for Kenya and The Netherlands, representing contrasting agricultural systems, and for the World. Total livestock excreta in 1996 were estimated to contain 94 million tonnes of N, 21 million tonnes of P, and 67 million tonnes of K. Cattle are the largest contributors with 60% of the total; pigs and poultry account for 10% and 9%. Nutrients recovered as manure were estimated as 34 million tonnes of N, 8.8 million tonnes of P, and 22.9 million tonnes of K. Recovery of excreta as manure from cattle is about 30%, but for pigs and poultry, which are usually housed, recovery is nearly 80%. As a percentage of total soil nutrient inputs, for N, manure accounts for 14%, for P 25%, and for K 20%. The contribution made by manure relative to fertilizers plus manure is declining. Since 1961, the percentages have decreased; for N from 60 to 25, for P from 50 to 38, and for K from 75 to 57. For most countries, percentages will decrease further as fertilizer use increases, but for some developed countries, such as The Netherlands and Japan, with large livestock industries, the percentage of manure is expected to increase and fertilizer demand will fall. For many developing countries manure will remain the main nutrient input. The production of livestock excreta and manure, and fertilizer use in Kenya and The Netherlands are discussed.