免疫亲和层析净化-超高效液相色谱法测定生鲜牦牛乳中黄曲霉毒素M_1及M_2

使用免疫亲和层析净化-超高效液相色谱法同时测定了生鲜牦牛乳中的黄曲霉毒素M_1(Aflatoxin M_1,AFM_1)及黄曲霉毒素M_2(Aflatoxin M_2,AFM_2)。黄曲霉毒素M_1仪器线性范围0.400-100μg/mL,仪器定量限0.400ng/mL,仪器检出限0.100ng/mL,方法检出限0.005μg/kg,回收率85.2-95.5%;黄曲霉毒素M_2仪器线性范围0.100-100μg/mL,仪器定量限0.100ng/mL,仪器检出限0.03ng/mL,方法检出限0.0015μg/kg,回收率82.1-93.8%。使用该方法对来自若尔盖地区的10个生鲜牦牛乳进行了测定,结果表明生鲜牦牛乳中黄曲霉毒素M_1和M_2安全可控。     

短小芽孢杆菌E-1-1-1中AFM_1降解酶的分离纯化

黄曲霉毒素M_1是黄曲霉毒素B_1的羟基化衍生物,主要存在于乳及乳制品中,对肝脏有致畸和致癌作用。目前人们对黄曲霉毒素M_1污染的关注度很高,解决黄曲霉毒素M_1污染问题越发重要。本文在先前研究的基础上,从短小芽孢杆菌(E-1-1-1)的发酵液中通过离心去菌体,硫酸铵沉淀,透析除盐制得粗酶液,再采用超滤,Sephadex G-75凝胶过滤,DEAE-Sepharose Fast Flow离子交换分离纯化获得一种电泳纯的黄曲霉毒素M_1的降解酶,AFM_1降解率为28.9%,经SDS-PAGE测定其分子质量约为58 ku。研究结果为后期进一步研究该降解酶的酶学性质及其降解机理提供了基础。     

乳与乳制品中黄曲霉毒素M_1的测定及卫生评价

黄曲霉毒素是黄曲霉及寄生曲霉中能产毒的菌株在繁殖过程中所产生的一类毒素,在粮食中以黄曲霉毒素B_1、B_8、G_1、G_2为主。本文对乳与乳制品中黄曲霉毒素M_1的测定方法进行了专题研究。样品经提取、净化制备成样液、通过硅胶G薄层板点样、经乙醚预展、展开剂展开,最后经乙醚上下反展,在紫外光365nm下观察其结果。本法不同于GB5009.24-85所规定的横展法,可一板点多个样液,提高了工作效率;同时,经反展后杂质上下移位,AFM_1出现背景无其它杂质干扰的蓝紫色萤光,避免了使用横展时由样液杂质与AFM_1斑点重叠而影响结果的观察。本法简便、快速、斑点清晰、灵敏度高,作者认为此法是目前工矿企业测定乳及乳制品中AFM_1含量较为理想的方法。     

RIDA~QUICK Aflatoxin黄曲霉毒素快速检测条:保障粮食收购的安全

黄曲霉毒素是黄曲霉、寄生曲霉等产生的代谢产物,对人、畜肝脏的损害程度为所有生物毒素之首,其中黄曲霉毒素B1的毒性是剧毒化学药品氰化钾的10倍以上,具有很强的致癌性,在1988年被国际癌症研究机构列为I级致癌物。黄曲霉毒素容易污染花生、玉米、大米、小麦、豆类、坚果类、肉类、乳及乳制品,水产品等食品,其中花生和玉米最容易受到污染。     

乳品中黄曲霉毒素M1检测方法研究进展

黄曲霉毒素M1是动物摄入黄曲霉毒素B1后的代谢产物,主要分布在动物的乳汁、尿液中。黄曲霉毒素M1毒性很大,经乳制品摄入会对人体产生巨大的危害。本文主要对乳品中黄曲霉毒素M1毒性、危害、检测方法进行综述。对主要检测方法的特性及适用范围进行分析与概括,并且对未来黄曲霉毒素M1的检测方法的发展进行了合理展望。     

超高效液相色谱-串联质谱法测定牛奶中的黄曲霉毒素M1

目的 建立超高效液相色谱-串联质谱测定牛奶中黄曲霉毒素M_1的方法。方法 采用Acquityuplc BEH C_(18)液相色谱柱(50 mm×2.1 mm,1.7μm),梯度洗脱,多反应监测(MRM)。通过黄曲霉毒素M_1与免疫亲和柱中抗体结合,确定了从牛奶中提取黄曲霉毒素M_1的处理条件并优化了质谱的测定参数。结果 黄曲霉毒素M_1在0.1~10.0 ng/ml的范围内线性良好,其回归标准曲线方程的相关系数为0.997 8,回收率94.8%~98.2%,RSD为2.34%~3.87%,方法定量限为0.005μg/kg。结论 提供了一种有效检测牛奶中黄曲霉毒素M_1的方法。     

粮油中黄曲霉毒素的预防及去除

<正> 黄曲霉与寄生曲霉中的一些菌株所产生的黄曲霉毒素是化合物中毒性与致癌性最强的物质之一。黄曲霉毒素不是一种单一的化合物,而是一大群结构十分相似的化合物。目前至少分离出17种化合物,分别命名为黄曲霉毒素B_1、B_2、B_(2a)、C_1、C_2、C_(2a)、M_1、M_2、P_1等。其中致癌性和中毒性最大的是B_1、另外C_1、C_2和M_1也具有强烈的毒性。它主要污染粮油及其制品如花生、花生油、花生仁、玉米、大米、棉籽等。世界各国对黄曲霉毒素对于人体造成的危害非常重视,联合国食品和农业组织、世界卫生组织建议食品中黄曲霉毒素限量为0.03mg/kg。我国在1977年的国家粮油食品卫生标准中规定:玉米、花生油、花生及     

乳酸菌对乳制品中黄曲霉毒素的生物防治作用

黄曲霉及其毒素污染常发生于乳制品中,导致一定的经济损失,且严重危害人体健康。乳酸菌及其代谢产物均可有效地吸附去除黄曲霉毒素。就黄曲霉毒素、乳酸菌生物防治作用、乳酸菌对乳制品中黄曲霉毒素生物防治作用的应用及安全性评价进行综述,为提高我国发酵乳制品的卫生安全质量提供理论依据。     

ThermoFisher Scientific检测食品中五种黄曲霉毒素的完整解决方案

黄曲霉毒素因具有致癌性及强急性毒性,所以在食品和农产品贸易中为必检项目,尤其经过蒙牛乳制品中黄曲霉毒素M1超标事件后,人们对黄曲霉毒素的关注愈来愈热.黄曲霉毒素是霉菌的二级代谢产物,目前主要关注的黄曲霉毒素有黄曲霉毒素B1、B2、G1、G2、M1,其中黄曲霉毒素B1的毒性和致癌性最强,而黄曲霉毒素M1是黄曲霉毒素B1的代谢物.我国规定,乳品及乳制品中黄曲霉毒素M1限量为0.5μg/kg,粮食中黄曲霉毒素B1为10μg/kg.     

乳制品企业利用HACCP原理控制奶牛饲料中的黄曲霉毒素M1的探讨

近期, 我国乳制品企业纯牛奶抽检结果中, 某产品黄曲霉毒素M1含量超出标准规定。由于黄曲霉毒素会对人体产生很大的伤害, 所以乳制品企业加强控制黄曲霉毒素含量相当重要。本文通过介绍黄曲霉标准限量、黄曲霉检测技术及乳制品企业对奶牛饲料中黄曲霉毒素M1的控制措施, 旨在探讨如何利用HACCP体系更好地控制饲料中的黄曲霉毒素M1, 确保乳制品的质量安全。     

Aflatoxin occurrence in milk and supplied concentrates of goat farms of north‐eastern Italy

BACKGROUND: There is little information about the occurrence of aflatoxin M₁ in goat milk. A survey involving 17 dairy goat farms of north‐eastern Italy was completed during 2005 and 2006, in order to evaluate the prevalence of milk contamination and its relationship with type and level of concentrate supplied. RESULTS: 132 concentrate and 85 milk samples were collected during five farm visits and analysed for aflatoxins. Aflatoxin B₁ (AFB₁) was > 0.1 µg kg^?1 in two‐thirds of the feeds and > 5 µg kg^?1 in nine. Contamination was higher in maize than in other pure feeds (median: 0.8 versus 0.1 µg kg^?1); complementary feeds showed intermediate values. Aflatoxin M₁ (AFM₁) was > 3 ng kg^?1 in one‐third of milks and > 25 ng kg^?1 in three. All the milk samples were below EU statutory limits. The farm ranks for milk AFM₁ level and the peak of concentrate AFB₁ contamination were significantly correlated (0.642). CONCLUSIONS: Risk to human health was generally found to be absent, with only a few cases involving feed contamination to be monitored. The main aflatoxin risk for goat milk could arise from maize and maize‐based concentrates in the more intensive breeding conditions. Copyright © 2008 Society of Chemical Industry     

Detection of aflatoxin M1 in milk,cheese and sour cream samples from Costa Rica using enzyme-assisted extraction and HPLC

Aflatoxins are toxic fungal metabolites, which can be found in feed. Aflatoxin M₁ (AFM₁) is excreted into milk when ruminants ingest aflatoxin B₁ contaminated feedstuffs. Due to its carcinogenic potential, contamination of milk and dairy products with AFM₁ may pose a risk for consumers. Hence, it is considered a public health concern. In this survey, the level of AFM₁ contamination of dairy products marketed in Costa Rica was determined by enzyme-assisted extraction, immunoaffinity clean-up and high-performance liquid chromatography coupled with a fluorescent detector (HPLC-FLD) in fluid milk (n = 70), fresh cheese (n = 70) and sour cream (n = 70) collected at local convenience stores and supermarkets. AFM₁ concentrations in milk and fresh cheese ranged from 19 to 629 ng/L and from 31 to 276 ng/L, with mean values of 136 ng/L and 74 ng/L, respectively, whereas none of the sour cream samples analysed tested positive for this aflatoxin. In 30 milk samples, and 10 cheese samples, AFM₁ concentrations surpassed threshold concentrations as established by the European Commission. Thus, sour cream and – to a lesser extent – cheese manufacturing seems to reduce the amount of AFM₁ present in milk, possibly due to fraction redistribution or microbiological degradation. The survey results reveal improper quality control procedures in the Costa Rican dairy industry. Therefore, a surveillance programme for dairy products in our country is recommended.     

Validation of a lateral flow test (MRLAFMQ) for the detection of aflatoxin M1 at 50 ng l−1 in raw commingled milk

Aflatoxin M₁ contamination in dairy products is a risk when feedstuff contaminated with aflatoxin B₁ produced by moulds is consumed by milk-producing animals. Milk can be screened for aflatoxin M₁ at the European Union maximum limit of 50 ng l^?1 by a lateral flow test, the MRLAFMQ (Aflatoxin M1) Test. The method takes 15 min with no milk dilution or a sample preparation step. The lateral flow assay was validated at the Technology and Food Science Unit of the Institute for Agricultural and Fisheries Research (ILVO-T&V) according to European Union guidelines using fortified raw milk samples. A detection capability of 50 ng l^?1 was demonstrated with a false negative rate lower than 2% at 50 ng l^?1 and a false positive rate of less than 0.3%. Quantitative readings had a mean bias of +2 to 6 ng l^?1 at 50 ng l^?1 with a standard deviation of 5–8 ng l^?1. Based on the validation results, the test could be considered appropriate for milk screening prior to milk unload at dairies.     

Aflatoxin M1 in Manufactured Dairy Products Produced in the United States in 1979

In a 1979 survey of manufactured dairy products (992 samples of nonfat dry milk, vanilla ice cream, yogurt, Cheddar cheese, and cottage cheese) for aflatoxin M₁ contamination, one sample, a cottage cheese, had detectable aflatoxin equivalent to .08 ng/ml in the milk from which the product was made. Samples were taken by Food and Drug District inspectors from randomly selected establishments at three times throughout the year. The distribution of sample quotas to each District was weighted to double the representation of establishments in the southern tier of states. The conclusion from this survey is that in a “normal” year aflatoxin M₁ should not be in a manufactured dairy product in the United States at a level in excess of that from milk with .1 ng aflatoxin M₁/ml.     

Mycotoxins in dairy products

Certain fungi produce chemical substances that cause toxic symptoms when food containing them is ingested by man or animals. These compounds are referred to as mycotoxins. Mycotoxins may contaminate dairy products by moulds growing on them, or by the carry-over of mycotoxins occurring in animal feedstuffs ingested by dairy cattle. An example of the first mentioned category is sterigmatocystin, a carcinogenic mycotoxin sometimes occurring on hard cheese. An example of the second category is aflatoxin M₁, a compound strongly suspected to be carcinogenic, which often occurs in milk. Due to the fact that processing of milk does not decrease the aflatoxin M₁ content, aflatoxin M₁ occurs in various dairy products. Sensitive methods of analysis for the determination of mycotoxins in dairy products have been developed in the last 10 years, most of them are based on TLC- or HPLC-separation procedures, followed by fluorimetric measurement.The most fundamental way to tackle the problem of mycotoxin contamination of dairy products is to prevent fungal growth on the dairy products or, in the case of carry-over of mycotoxins, in the crop before, during and after harvest. If measures to prevent fungal growth and mycotoxins production are not taken or fail, one can sometimes resort to physical or chemical methods to eliminate mycotoxins.     

Assessment of aflatoxin M1 levels in selected dairy products in north‐western Iran

The purpose of this survey was to evaluate the natural occurrence and content of aflatoxin M_1, AFM_1, in dairy products marketed in Urmia. During September 2007, 40 samples of pasteurised milk, 40 samples of ultra high temperature‐treated (UHT) milk, 40 samples of creamy cheese and 40 samples of Iranian Feta cheese were collected from different supermarkets in Urmia city. AFM₁ contents were determined by the competitive enzyme‐linked imunosorbent assay (ELISA) technique. All milk samples analysed showed a mean of AFM₁ concentrations lower than the permissible level of 50 ng/kg in Iran (23.22 and 19.53 ng/kg in pasteurised milk and UHT milk respectively). The mean levels of AFM₁ contamination were 43.31 ng/kg in Feta cheeses and 21.96 ng/kg in creamy cheeses. The potential risk of human exposure to aflatoxin M₁ via consumption of milk and milk products is well known. Dairy products must therefore be evaluated for aflatoxin and kept free from fungal contamination as much as possible.     

Effects of different sources of Saccharomyces cerevisiae biomass on milk production,composition, and aflatoxin M1 excretion in milk from dairy cows fed aflatoxin B1

The aim of the present study was to evaluate the effect of different sources of Saccharomyces cerevisiae (SC) biomass (20.0 g/d) obtained from sugarcane (cell wall, CW; dried yeast, DY; autolyzed yeast, AY) and the beer industry (partially dehydrated brewery yeast, BY) on milk production, fat and protein percentages, and aflatoxin M₁ (AFM₁) excretion in milk from dairy cows receiving 480 µg aflatoxin B₁ (AFB₁) per day. A completely randomized design was used with 2 lactating cows assigned to each of 10 dietary treatments, as follows: negative controls (no AFB₁ or SC-based biomass), positive controls (AFB₁ alone), DY alone, DY + AFB₁, BY alone, BY + AFB₁, CW alone, CW + AFB₁, AY alone, and AY + AFB₁. The cows in the aflatoxin treatment group received AFB₁ from d 1 to 6, while the SC biomass was administered with the AFB₁ bolus from d 4 to 6. Aflatoxin B₁ or SC-based products did not affect milk production or milk composition during the experimental period. Aflatoxin M₁ was detected in the milk from all aflatoxin treatment group cows, reaching maximum levels at d 3 and varying from 0.52 ± 0.03 to 1.00 ± 0.04 µg/L. At end of the treatment period, CW, AY, DY, and BY removed 78%, 89%, 45%, and 50% of AFM₁ from the milk, respectively, based on the highest level found on d 3. Results indicate a potential application of industrial fermentation by-products, especially CW and AY, as a feed additive in the diets of dairy cows to reduce the excretion of AFM₁ in milk.     

An effective self-control strategy for the reduction of aflatoxin M1 content in milk and to decrease the exposure of consumers

The study reports the results of testing the sensitivity of an early warning sampling plan for detecting milk batches with high aflatoxin AFM₁ concentration. The effectiveness of the method was investigated by the analysis of 9017 milk samples collected in Italian milk processing plants that applied control plans with different action limits (AL). For those milk processing plants where 30 ng kg^?1 AL has been applied, the AFM₁ contamination was significantly lower at or above the 95th percentile of the milk samples when compared with plants that used 40 ng kg^?1 AL. The results show that the control plan can be used effectively for early warning of occurrence of high AFM₁ contamination of milk and to carry out pro-active measures to limit the level of contamination. Estimation of dietary exposure was also carried out, based on the aflatoxin M₁ content of the milk samples and on Italian food consumption data. Estimated Daily Intakes (EDI) and Hazard Indices (HI) were calculated for different age groups of the population. HIs show that no adverse effects are expected for the adult population, but in the case of children under age three, the approximate HI values were considerably higher. This underlines the importance of the careful monitoring and control of aflatoxin M₁ in milk and dairy products.     

Current Immunoassay Methods for the Rapid Detection of Aflatoxin in Milk and Dairy Products

The presence of mycotoxins in foodstuff causes serious health problems to consumers and economically affects the food industry. Among the mycotoxins, aflatoxins are very toxic and highly carcinogenic contaminants which affect the safety of many foods, and therefore endanger human health. Aflatoxin M₁ (AFM₁) found in milk results from the biotransformation of aflatoxin B₁. Many efforts have been made to control the source of AFM₁ from farmers to dairy product companies. However, AFM₁ escapes ordinary methods of food treatment such as cooking, sterilization, and freezing, hence it appears in milk and dairy products. The presence of high levels of AFM₁ constitutes an alarming threat as milk and dairy products contain essential nutrients for human health, especially for infants and children. For this reason, there is a pressing need for developing a fast and reliable screening method for detecting trace aflatoxins in food. Several analytical methods based on high‐performance liquid chromatography (HPLC) and mass spectroscopy have been used for aflatoxin detection; however, they are expensive, time‐consuming, and require many skills. Recently, immunoassay methods, including enzyme‐linked immunosorbent assay (ELISA), immunosensors, and lateral flow immunoassay (LFIA), have been preferred for food analysis because of their improved qualities such as high sensitivity, simplicity, and capability of onsite monitoring. This paper reviews the new developments and applications of immunoassays for the rapid detection of AFM₁ in milk.