Saccharomyces cerevisiae strains and the reduction of Aspergillus parasiticus growth and aflatoxin B1 production at different interacting environmental conditions,in vitro

The effect of Saccharomyces cerevisiae RC008 and RC016, previously selected based on their aflatoxin B₁ binding ability and beneficial properties, against Aspergillus parasiticus under different interacting environmental conditions was evaluated. Studies concerning the lag phase, growth rate and aflatoxin B₁ production were carried out in vitro under different regimes of a _w (0.95 and 0.99), pH (4 and 6), temperature (25 and 37°C), and oxygen availability (normal and reduced). Both yeast strains showed great antagonistic activity at pH 4, decreasing growth rate compared with the control. The RC008 strain showed the greatest inhibitory activity at all assayed conditions. A. parasiticus produced large amounts of AFB₁ in vitro. A significant decrease of AFB₁ levels in comparison with the control were observed with yeast interaction. Differences between control and treatment values ranged from 130 to 5400?ng?ml^?1. S. cerevisiae RC008 and RC016 could be considered as effective agents in reducing growth and AFB₁ production at different interacting environmental conditions, related to that found in stored feedstuff. The importance of the present work lies in the search for live strains with both probiotic and biocontrol properties able to prolong the safe storage of feedstuff and exert beneficial properties after animal consumption and which could be included in a novel product for animal feed.     

Aflatoxin Removal from Pistachio Nuts by Natural Natrolite

ABSTRACT: Natrolite was used to explore a physical and safe method to decontaminate aflatoxin-containing pistachio lots. Pistachio nuts with low, medium, and high levels of aflatoxin were subjected to a washing process with a slurry of 5% natrolite. Using thin-layer chromatography and scanning, the aflatoxin contents of the samples were measured. Aflatoxins B₁ and B₂ were found in pistachio nuts. The majority of total aflatoxins was aflatoxin B₁ Natrolite treatment resulted in a 38% to 100% reduction in aflatoxin B₁, depending on the initial aflatoxin level. Although natrolite was demonstrated to be an effective candidate to reduce aflatoxin B₁, its efficacy against aflatoxin B₂ was limited.     

Toxic Compounds Formed on Prolonged Heating of Citrinin under Watery Conditions

Citrinin was partially decomposed by heating under aqueous conditions at 90°C for > 10 min and a group of degraded compounds (Group I) was detected by TLC. At 100°C and 110°C, citrinin disappeared rapidly, and the cytotoxicity of the samples increased with prolonged heating. At 120°C, citrinin disappeared more rapidly while TLC spots of Group I compounds also diminished upon >20 min heating and a new group of compounds (Group II) appeared. Cytotoxicity decreased rapidly at > 120°C and was eliminated after 10 min at 130°C. Group I appeared to contain toxic compound(s) but Group II did not. Heating citrinin under conditions similar to cooking may cause formation of additional cytotoxic compounds.     

Efficiency of different extraction solvent mixtures used in analyses of aflatoxins from a certified peanut meal reference material

Four analytical methods with different extraction solvent mixtures were used to compare the efficiency of the extraction step in the analysis of aflatoxins from a reference material with a certified value of 206 ± 13 µg aflatoxin B₁ kg^-1. The extraction mixtures used were chloroform-water (100 + 10), acetonitrile-water (60 + 40), acetone-water (85 + 15) and methanol-water (80 + 20). The analytical values determined from the extraction mixtures after correction for recovery were 211, 204, 163 and 120 µg kg^-1, respectively. The small amounts of aflatoxin B₂ in the reference material followed the same pattern. The selection of extraction solvent mixture is very important for achieving the true value and that correction for recovery does not always fully compensate for getting the correct analytical value.     

Induction of chitinase in response to Aspergillus infection in sorghum (Sorghum bicolor (L) Moench)

Chitinase is an antifungal protein which is induced in higher plants during infection and stress. In this paper the induction of chitinase activity in response to infection by Aspergillus parasiticus (NRRL 2999) in six sorghum (Sorghum bicolor (L) Moench) genotypes and its association with aflatoxin production were investigated. Chitinase was induced in all six genotypes (two each of red, yellow and white sorghum) when infected by A parasiticus (NRRL 2999). The induction of chitinase activity was highest in the white cultivars, followed by the yellow and red genotypes, compared with healthy grains. In the white cultivars the chitinase activity increased on the 6th and 9th days after infection and was four‐ to fivefold higher than in healthy grains. The total aflatoxin produced was lower in the red genotypes than in the yellow and white genotypes. The white genotypes showed maximum total aflatoxin production at 6 days after infection. The aflatoxins produced in the white genotypes were comparable to those in the red genotypes. There was a significant positive correlation between chitinase activity and aflatoxin production in red sorghum (r² = 0.600, p ≤ 0.001) and white sorghum (r² = 0.411, p ≤ 0.001). Maximum chitinase activity was observed on day 12 in all genotypes under healthy conditions. Copyright © 2004 Society of Chemical Industry     

微流控芯片液液萃取结合超高效液相色谱-串联质谱法检测玉米油中黄曲霉毒素B1

目的 建立基于双Y型层流和三相层流微流控芯片的液液萃取技术,结合超高效液相色谱-串联质谱法检测玉米油中黄曲霉毒素B1的方法。方法 设计了双通道和三通道入口的的两种芯片,对芯片通道表面经过前处理,用注射泵引入含有黄曲霉毒素B1的样品溶液及萃取剂甲醇溶液于芯片中进行液液萃取,将所得的萃取液进行超高效液相色谱-串联质谱检测。对样品溶液与萃取剂的流速、芯片萃取通道的宽度等因素进行考察。结果 经纯水处理风干后的芯片,样品溶液流速为200 μL/h、甲醇流速为300μL/h,萃取通道宽度为 200μm的三相层流微流控芯片的萃取效果更好。在最优流速下平行实验6次,RSD为5.6%,芯片对黄曲霉毒素B1的萃取率为96.8%。结论 三相层流微流控芯片比双Y型层流微流控芯片对黄曲霉毒素B1的萃取率更高、萃取时间更短,并为检测其他食品污染物提供参考。     

二乙烯三胺脱除花生粕中黄曲霉毒素B1的工艺优化及机制研究

旨在为霉变花生粕中黄曲霉毒素B₁(AFB₁)的脱除提供技术支持,以自然霉变花生粕为实验材料,用二乙烯三胺脱除花生粕中的AFB₁。采用单因素实验优化脱毒条件,并对二乙烯三胺脱除AFB₁的机制进行研究。结果表明：二乙烯三胺脱除花生粕中AFB₁的最佳工艺条件为液料比5∶1、处理温度50℃、处理时间45 min、二乙烯三胺溶液质量浓度10 mg/mL,在此条件下AFB₁脱除率为95.5%;高效液相色谱和高分辨质谱分析表明,AFB₁可能的降解机制是其酮羰基与二乙烯三胺发生脱水反应,并且反应产物通过离心随着上清液被脱除。二乙烯三胺具有应用于花生粕中AFB₁脱除的潜力。     

发酵调味品中黄曲霉毒素检测控制技术概论

黄曲霉毒素是发酵调味品中最大的安全隐患,研究其检测和控制技术是发酵调味品安全控制的重点。文章论述了发酵制品黄曲霉毒素检测控制的重要性及相关的技术,分析了发酵制品中黄曲霉毒素控制技术的发展前景。     

花生油加工与贮藏过程中的主要安全问题研究

花生油因能提供独特的风味和多种营养而广受消费者喜爱,但其潜在的安全问题也引起人们的顾虑。本文主要评述花生原料和花生油在加工贮藏过程中产生的黄曲霉毒素、苯并芘和塑化剂等危害物质,并根据最新的研究报道针对花生油中存在的安全问题进行综述分析,提出相应的解决措施,为花生油健康发展提供参考。     

广东小作坊生产花生油中黄曲霉毒素B1膳食暴露及风险评估

对广东居民通过小作坊花生油对黄曲霉毒素B_1的膳食暴露及其产生的健康风险进行评价。采用点评估模型对广东不同年龄人群通过花生油对黄曲霉毒素B_1的膳食暴露情况进行评估,按照联合国粮农组织和世界卫生组织食品添加剂联合专家委员会推荐的方法对黄曲霉毒素B_1引发的肝癌风险进行评价。结果表明:2017年广东地区小作坊花生油黄曲霉毒素B_1超标率11. 8%,检出率56. 9%;各年龄组高消费水平暴露量规律为7～14岁 15～50岁 50岁以上 2～6岁,15～50岁、50岁以上、2～6岁3个年龄段女性高消费水平暴露量大于男性;高消费人群由于花生油中黄曲霉毒素B1的膳食暴露引发肝癌的风险为7～14岁男性少年儿童危险度最大,高消费水平肝癌贡献率最高,达28. 9%。高消费人群花生油中黄曲霉毒素B_1引发肝癌的风险相对较高,应对全省小作坊花生油黄曲霉毒素污染予以足够的重视。