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Tan S, Ma F, Wu Y, Xu Y, Niu A, Chen Y, Wang G, Qiu W. The biodiversity of Aspergillus flavus in stored rice grain leads to a decrease in the overall aflatoxin B 1 production in these species. Int J Food Microbiol 2023; 406:110416. [PMID: 37769398 DOI: 10.1016/j.ijfoodmicro.2023.110416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/11/2023] [Accepted: 09/22/2023] [Indexed: 09/30/2023]
Abstract
Aspergillus flavus is a significant fungus that poses a threat to food safety by producing mycotoxins in various crops. In this study, A. flavus isolates were obtained from storage rice collected from seven provinces in southern China, and their AFB1 production, biosynthesis genes presence, and diversity were detected. Results showed that 56 out of the 81 A. flavus isolates produced detectable levels of AFB1, and 71 isolates (87.6 %) possessed aflR gene in their AF synthesis gene cluster, while only 41 isolates (50.6 %) had the ver-1 gene present. Genetic diversity analysis using inter-simple sequence repeats (ISSR) markers revealed seven main clusters among the isolates and the genetic similarity coefficients of 81 A. flavus isolates ranged from 0.53 to 1.00. Additionally, coculture assays were conducted using two toxigenic and two atoxigenic isolates from the same grain depot to investigate the effect of intraspecific inhibition on AFB1 production and to assess the AFB1 contamination risk of storage rice. The in situ results demonstrated that the atoxigenic isolates effectively inhibited the AFB1 contamination of toxigenic isolates. These findings provide insight into the genetic diversity of A. flavus isolates populations and highlight the potential food safety hazards of them in stored rice grain in China.
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Affiliation(s)
- Song Tan
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Fang Ma
- Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Yajie Wu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Yuancheng Xu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Ajuan Niu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Yuping Chen
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Guangyu Wang
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China.
| | - Weifen Qiu
- College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210023, China; Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210023, China; Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
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2
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Aladhadh M. A Review of Modern Methods for the Detection of Foodborne Pathogens. Microorganisms 2023; 11:1111. [PMID: 37317085 DOI: 10.3390/microorganisms11051111] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 06/16/2023] Open
Abstract
Despite the recent advances in food preservation techniques and food safety, significant disease outbreaks linked to foodborne pathogens such as bacteria, fungi, and viruses still occur worldwide indicating that these pathogens still constitute significant risks to public health. Although extensive reviews of methods for foodborne pathogens detection exist, most are skewed towards bacteria despite the increasing relevance of other pathogens such as viruses. Therefore, this review of foodborne pathogen detection methods is holistic, focusing on pathogenic bacteria, fungi, and viruses. This review has shown that culture-based methods allied with new approaches are beneficial for the detection of foodborne pathogens. The current application of immunoassay methods, especially for bacterial and fungal toxins detection in foods, are reviewed. The use and benefits of nucleic acid-based PCR methods and next-generation sequencing-based methods for bacterial, fungal, and viral pathogens' detection and their toxins in foods are also reviewed. This review has, therefore, shown that different modern methods exist for the detection of current and emerging foodborne bacterial, fungal, and viral pathogens. It provides further evidence that the full utilization of these tools can lead to early detection and control of foodborne diseases, enhancing public health and reducing the frequency of disease outbreaks.
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Affiliation(s)
- Mohammed Aladhadh
- Department of Food Science and Human Nutrition, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah 51452, Saudi Arabia
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3
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Yu J, Guo M, Jiang W, Dao Y, Pang X. Illumina-Based Analysis Yields New Insights Into the Fungal Contamination Associated With the Processed Products of Crataegi Fructus. Front Nutr 2022; 9:883698. [PMID: 35634418 PMCID: PMC9135361 DOI: 10.3389/fnut.2022.883698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/13/2022] [Indexed: 12/12/2022] Open
Abstract
Crataegi Fructus, a medicinal and edible herb in China, has been considered a popular dietary supplement globally. It is used for the treatment of dyspepsia and chronic heart failure according to the Chinese Pharmacopoeia (2020). However, fungal contamination in Crataegi Fructus affects its quality and safety, thus preventing its global promotion. In this study, we comprehensively studied the fungal community in processed products of Crataegi Fructus by high-throughput sequencing. A total of 21 Crataegi Fructus samples were collected from five provinces in China, and the samples were divided into five groups based on collection areas, as well as into three groups based on processing methods. We then targeted the internal transcribed spacer 2 sequence through the Illumina Miseq PE300 platform to investigate fungal composition and diversity. Results showed that all 21 samples were detected with fungal contamination, and Ascomycota was dominant at the phylum level. In the groups based on collection areas, Dothideomycetes, Pleosporaceae, and Alternaria were dominant at the class, family, and genus levels, respectively. In the groups based on processing methods, Dothideomycetes, Aspergillaceae, and Alternaria were the most abundant at the class, family, and genus levels, respectively. Differences in fungal communities between various groups were also observed. Furthermore, a total of 115 species were identified, among which seven were potential toxigenic, namely, Trichothecium roseum, Alternaria tenuissima, Aspergillus carbonarius, Penicillium brevicompactum, Aspergillus fumigatus, Rhizopus microspores, and Pichia fermentans. In conclusion, this study reveals great fungal richness and diversity of Crataegi Fructus, providing references for the prevention and control of fungal contamination of Crataegi Fructus in practical production.
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Rahman HU, Yue X, Yu Q, Zhang W, Zhang Q, Li P. Current PCR-based methods for the detection of mycotoxigenic fungi in complex food and feed matrices. WORLD MYCOTOXIN J 2020. [DOI: 10.3920/wmj2019.2455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Mycotoxins are toxic secondary fungal metabolites produced by certain types of filamentous fungi, such as Aspergillus, Fusarium, and Penicillium spp. Mycotoxigenic fungi and their produced mycotoxins are considered to be an important issue in food and feed safety due to their toxic effects like carcinogenicity, immunosuppression, neurotoxicity, nephrotoxicity, and hepatotoxicity on humans and animals. To boost the safety level of food and feedstuff, detection and identification of toxins are essential at critical control points across food and feed chains. Zero-tolerance policies by the European Union and other organizations about the extreme low level of tolerance of mycotoxins contamination in food and feed matrices have led to an increasing interest to design more sensitive, specific, rapid, cost-effective, and safer to use mycotoxigenic fungi detection technologies. Hence, many mycotoxigenic fungi detection technologies have been applied to measure and control toxins contamination in food and feed substrates. PCR-based mycotoxigenic fungi detection technologies, such as conventional PCR, real-time PCR, nested PCR, reverse transcriptase (RT)-PCR, loop-mediated isothermal amplification (LAMP), in situ PCR, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR DGGE), co-operational PCR, multiplex PCR, DNA arrays, magnetic capture-hybridization (MCH)-PCR and restriction fragment length polymorphism (RFLP), would contribute to our understanding about different mycotoxigenic fungi detection approaches and will enhance our capability about mycotoxigenic fungi identification, isolation and characterization at critical control points across food and feed chains. We have assessed the principles, results, the limit of detection, and application of these PCR-based detection technologies to alleviate mycotoxins contamination problem in complex food and feed substrates. The potential application of these detection technologies can reduce mycotoxins in complex food and feed matrices.
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Affiliation(s)
- H. Ur Rahman
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China P.R
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China P.R
- Key Laboratory of Detection for Mycotoxins, Ministry of Agriculture, Wuhan 430062, China P.R
| | - X. Yue
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China P.R
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China P.R
- Laboratory of Quality & Safety Risk Assessment for Oilseeds Products, Wuhan, Ministry of Agriculture, Wuhan 430062, China P.R
| | - Q. Yu
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China P.R
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China P.R
- Key Laboratory of Detection for Mycotoxins, Ministry of Agriculture, Wuhan 430062, China P.R
- National Reference Laboratory for Agricultural Testing (Biotoxin), Wuhan 430062, China P.R
| | - W. Zhang
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China P.R
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China P.R
- Quality Inspection and Test Center for Oilseeds Products, Ministry of Agriculture, Wuhan 430062, China P.R
| | - Q. Zhang
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China P.R
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China P.R
- Laboratory of Quality & Safety Risk Assessment for Oilseeds Products, Wuhan, Ministry of Agriculture, Wuhan 430062, China P.R
| | - P. Li
- Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China P.R
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China P.R
- Key Laboratory of Detection for Mycotoxins, Ministry of Agriculture, Wuhan 430062, China P.R
- Laboratory of Quality & Safety Risk Assessment for Oilseeds Products, Wuhan, Ministry of Agriculture, Wuhan 430062, China P.R
- National Reference Laboratory for Agricultural Testing (Biotoxin), Wuhan 430062, China P.R
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5
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Rao KR, Vipin AV, Venkateswaran G. Molecular profile of non-aflatoxigenic phenotype in native strains of Aspergillus flavus. Arch Microbiol 2020; 202:1143-1155. [PMID: 32062689 DOI: 10.1007/s00203-020-01822-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/13/2020] [Accepted: 01/28/2020] [Indexed: 11/26/2022]
Abstract
Aflatoxins are the most common mycotoxin contaminant reported in food and feed. Aflatoxin B1, the most toxic among different aflatoxins, is known to cause hepatocellular carcinoma in animals. Aspergillus flavus and A. parasiticus are the main producers of aflatoxins and are widely distributed in tropical countries. Even though several robust strategies have been in use to control aflatoxin contamination, the control at the pre-harvest level is primitive and incompetent. Therefore, the aim of the study was to isolate and identify the non-aflatoxigenic A. flavus and to delineate the molecular mechanism for the loss of aflatoxin production by the non-aflatoxigenic isolates. Eighteen non-aflatoxigenic strains were isolated from various biological sources using cultural and analytical methods. Among the 18 isolates, 8 isolates produced sclerotia and 17 isolates had type I deletion in norB-cypA region. The isolates were confirmed as A. flavus using gene-specific PCR and sequencing of the ITS region. Later, aflatoxin gene-specific PCR revealed that the defect in one or more genes has led to non-aflatoxigenic phenotype. The strain R9 had maximum defect, and genes avnA and verB had the highest frequency of defect among the non-aflatoxigenic strains. Further, qRT-PCR confirmed that the non-aflatoxigenic strains had high frequency of defect or downregulation in the late pathway genes compared to early pathway genes. Thus, these non-aflatoxigenic strains can be the potential candidates for an effective and proficient strategy for the control of pre-harvest aflatoxin contamination.
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Affiliation(s)
- K Raksha Rao
- Microbiology and Fermentation Technology, CSIR-Central Food Technological Research Institute, Mysuru, Karnataka, 570 020, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Food Technological Research Institute Campus, Mysuru, Karnataka, 570 020, India
| | - A V Vipin
- Microbiology and Fermentation Technology, CSIR-Central Food Technological Research Institute, Mysuru, Karnataka, 570 020, India
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Food Technological Research Institute Campus, Mysuru, Karnataka, 570 020, India
| | - G Venkateswaran
- Microbiology and Fermentation Technology, CSIR-Central Food Technological Research Institute, Mysuru, Karnataka, 570 020, India.
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Central Food Technological Research Institute Campus, Mysuru, Karnataka, 570 020, India.
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6
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Zhao G, Wang YF, Chen J, Yao Y. Predominant Mycotoxins, Pathogenesis, Control Measures, and Detection Methods in Fermented Pastes. Toxins (Basel) 2020; 12:E78. [PMID: 31979410 PMCID: PMC7076863 DOI: 10.3390/toxins12020078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 01/12/2020] [Accepted: 01/21/2020] [Indexed: 12/19/2022] Open
Abstract
Fermented pastes are some of the most popular traditional products in China. Many studies reported a strong possibility that fermented pastes promote exposure to mycotoxins, including aflatoxins, ochratoxins, and cereulide, which were proven to be carcinogenic and neurotoxic to humans. The primary mechanism of pathogenicity is by inhibiting protein synthesis and inducing oxidative stress using cytochrome P450 (CYP) enzymes. The level of mycotoxin production is dependent on the pre-harvest or post-harvest stage. It is possible to implement methods to control mycotoxins by using appropriate antagonistic microorganisms, such as Aspergillus niger, Lactobacillus plantarum, and Saccharomyces cerevisiae isolated from ordinary foods. Also, drying products as soon as possible to avoid condensation or moisture absorption in order to reduce the water activity to lower than 0.82 during storage is also effective. Furthermore, organic acid treatment during the soaking process reduces toxins by more than 90%. Some novel detection technologies based on magnetic adsorption, aptamer probes, and molecular-based methods were applied to rapidly and accurately detect mycotoxins in fermented pastes.
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Affiliation(s)
- Guozhong Zhao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Engineering, Tianjin University of Science & Technology, 300457 Tianjin, China; (G.Z.); (Y.-F.W.)
| | - Yi-Fei Wang
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Engineering, Tianjin University of Science & Technology, 300457 Tianjin, China; (G.Z.); (Y.-F.W.)
| | - Junling Chen
- College of Food and Bioengineering, Henan University of Science and Technology, 471023 Luoyang, China;
| | - Yunping Yao
- State Key Laboratory of Food Nutrition and Safety, Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Science and Engineering, Tianjin University of Science & Technology, 300457 Tianjin, China; (G.Z.); (Y.-F.W.)
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7
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Norlia M, Jinap S, Nor-Khaizura MAR, Radu S, Chin CK, Samsudin NIP, Farawahida AH. Molecular Characterisation of Aflatoxigenic and Non-Aflatoxigenic Strains of Aspergillus Section Flavi Isolated from Imported Peanuts along the Supply Chain in Malaysia. Toxins (Basel) 2019; 11:E501. [PMID: 31470527 PMCID: PMC6784170 DOI: 10.3390/toxins11090501] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/25/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022] Open
Abstract
Peanuts are widely consumed in many local dishes in southeast Asian countries, especially in Malaysia which is one of the major peanut-importing countries in this region. Therefore, Aspergillus spp. and aflatoxin contamination in peanuts during storage are becoming major concerns due to the tropical weather in this region that favours the growth of aflatoxigenic fungi. The present study thus aimed to molecularly identify and characterise the Aspergillus section Flavi isolated from imported peanuts in Malaysia. The internal transcribed spacer (ITS) and β-tubulin sequences were used to confirm the species and determine the phylogenetic relationship among the isolates, while aflatoxin biosynthesis genes (aflR, aflP (omtA), aflD (nor-1), aflM (ver-1), and pksA) were targeted in a multiplex PCR to determine the toxigenic potential. A total of 76 and one isolates were confirmed as A. flavus and A. tamarii, respectively. The Maximum Likelihood (ML) phylogenetic tree resolved the species into two different clades in which all A. flavus (both aflatoxigenic and non-aflatoxigenic) were grouped in the same clade and A. tamarii was grouped in a different clade. The aflatoxin biosynthesis genes were detected in all aflatoxigenic A. flavus while the non-aflatoxigenic A. flavus failed to amplify at least one of the genes. The results indicated that both aflatoxigenic and non-aflatoxigenic A. flavus could survive in imported peanuts and, thus, appropriate storage conditions preferably with low temperature should be considered to avoid the re-emergence of aflatoxigenic A. flavus and the subsequent aflatoxin production in peanuts during storage.
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Affiliation(s)
- Mahror Norlia
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- School of Industrial Technology, Universiti Sains Malaysia, Minden 11800, Pulau Pinang, Malaysia
| | - Selamat Jinap
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
| | - Mahmud Ab Rashid Nor-Khaizura
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Son Radu
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Cheow Keat Chin
- Food Safety and Quality Division, Ministry of Health Malaysia, Putrajaya 62675, Malaysia
| | - Nik Iskandar Putra Samsudin
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
- Laboratory of Food Safety and Food Integrity, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
| | - Abdul Halim Farawahida
- Department of Food Science and Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia
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8
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Genetic Diversity of Fungi Producing Mycotoxins in Stored Crops. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.4.15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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9
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Zhang SY, Wang H, Yang M, Yao DS, Xie CF, Liu DL. Versicolorin A is a potential indicator of aflatoxin contamination in the granary-stored corn. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2018; 35:972-984. [PMID: 29337658 DOI: 10.1080/19440049.2017.1419579] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The objective of this study was to evaluate the feasibility of the predictive monitoring of aflatoxin B1 (AFB1) under granary conditions, since mycotoxin contamination of the stored grain represents an important issue. Using the storage test, we investigated the relationship between versicolorin A (Ver A, an intermediate in AFB1 biosynthesis) levels and the levels of aflatoxigenic fungi, and their relationship with aflatoxin production. All samples, except for one, were found to be contaminated with aflatoxigenic fungi using PCR analyses, while their AFB1 levels were not detectable before the storage test using an enzyme-linked immunosorbent assay (ELISA) method with an LOD of 2 μg/kg. Aflatoxigenic fungi levels were analysed, as well as Ver A levels prior to the accumulation of AFB1 (Levels were ≥5 μg/kg; the permissible levels of AFB1 in corn intended for direct consumption are <5 μg/kg (EC)). Statistical analyses demonstrated that aflatoxin levels after both actual storage and safe storage (AFB1˂5μg/kg) times are significantly correlated with the Ver A levels and the changes in Ver A levels (ΔVer A). Both high and variable Ver A levels were indicative of the vigorous metabolic activity of aflatoxigenic fungi. In contrast, steady Ver A levels showed that aflatoxin production by the fungi was not active. Monitoring Ver A levels and their changes may allow an earlier detection of harmful aflatoxin contamination in the stored grain. Additionally, the toxicity of Ver A should be further examined. The results of our study indicate that the monitoring of Ver A levels, even when the AFB1 levels are very low, may increase the safety of grain consumption, especially considering Ver A toxicity.
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Affiliation(s)
- Shu-Yao Zhang
- a Department of Biotechnology, College of Life Science and Technology , Jinan University , Guangzhou , China.,b State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application , Guangdong Institute of Microbiology , Guangzhou , China.,c Institute of Microbial Biotechnology , Jinan University , Guangzhou , China
| | - Hao Wang
- a Department of Biotechnology, College of Life Science and Technology , Jinan University , Guangzhou , China.,c Institute of Microbial Biotechnology , Jinan University , Guangzhou , China
| | - Min Yang
- a Department of Biotechnology, College of Life Science and Technology , Jinan University , Guangzhou , China.,c Institute of Microbial Biotechnology , Jinan University , Guangzhou , China
| | - Dong-Sheng Yao
- a Department of Biotechnology, College of Life Science and Technology , Jinan University , Guangzhou , China.,c Institute of Microbial Biotechnology , Jinan University , Guangzhou , China.,d National Engineering Research Centre of Genetic Medicine , Guangzhou , China
| | - Chun-Fang Xie
- a Department of Biotechnology, College of Life Science and Technology , Jinan University , Guangzhou , China.,c Institute of Microbial Biotechnology , Jinan University , Guangzhou , China.,d National Engineering Research Centre of Genetic Medicine , Guangzhou , China
| | - Da-Ling Liu
- a Department of Biotechnology, College of Life Science and Technology , Jinan University , Guangzhou , China.,c Institute of Microbial Biotechnology , Jinan University , Guangzhou , China
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10
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Sadhasivam S, Britzi M, Zakin V, Kostyukovsky M, Trostanetsky A, Quinn E, Sionov E. Rapid Detection and Identification of Mycotoxigenic Fungi and Mycotoxins in Stored Wheat Grain. Toxins (Basel) 2017; 9:toxins9100302. [PMID: 28946706 PMCID: PMC5666349 DOI: 10.3390/toxins9100302] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 02/06/2023] Open
Abstract
This study aimed to assess the occurrence of toxigenic fungi and mycotoxin contamination in stored wheat grains by using advanced molecular and analytical techniques. A multiplex polymerase chain reaction (PCR) strategy was established for rapid identification of mycotoxigenic fungi, and an improved analytical method was developed for simultaneous multi-mycotoxin determination in wheat grains by liquid chromatography-tandem mass spectrometry (LC/MS/MS) without the need for any clean-up. The optimized multiplex PCR method was highly specific in detecting fungal species containing species-specific and mycotoxin metabolic pathway genes. The method was applied for evaluation of 34 wheat grain samples collected from storage warehouses for the presence of mycotoxin-producing fungi, and a few samples were found positive for Fusarium and Aspergillus species. Further chemical analysis revealed that 17 samples contained mycotoxins above the level of detection, but only six samples were found to be contaminated over the EU regulatory limits with at least one mycotoxin. Aflatoxin B1, fumonisins, and deoxynivalenol were the most common toxins found in these samples. The results showed a strong correlation between the presence of mycotoxin biosynthesis genes as analyzed by multiplex PCR and mycotoxin detection by LC/MS/MS. The present findings indicate that a combined approach might provide rapid, accurate, and sensitive detection of mycotoxigenic species and mycotoxins in wheat grains.
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Affiliation(s)
- Sudharsan Sadhasivam
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel.
| | - Malka Britzi
- National Residue Control Laboratory, Kimron Veterinary Institute, Bet Dagan 50250, Israel.
| | - Varda Zakin
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel.
| | - Moshe Kostyukovsky
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel.
| | - Anatoly Trostanetsky
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel.
| | - Elazar Quinn
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel.
| | - Edward Sionov
- Department of Food Quality and Safety, Institute for Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7528809, Israel.
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11
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Zheng RS, Wang WL, Tan J, Xu H, Zhan RT, Chen WW. An investigation of fungal contamination on the surface of medicinal herbs in China. Chin Med 2017; 12:2. [PMID: 28053655 PMCID: PMC5209813 DOI: 10.1186/s13020-016-0124-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 12/19/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The dried parts of medicinal herbs are susceptible to the infection of fungi during pre- or post-harvest procedure. This study aimed to investigate the presence of fungi and their metabolites mycotoxins on the surface of medicinal herbs collected from China. METHODS Forty-five retail samples of 15 different medicinal herbs were collected from 3 different regions in China. Then the potential fungi were immediately washed off from the surface of each sample with 0.1% Tween-20 followed by incubation of the rinse on petri-dish with potato dextrose agar containing chloramphenicol at 28 °C. The obtained fungi were isolated as single colonies and then characterized by morphology and molecular identification using internal transcribed spacer (ITS) sequencing with extracted DNA. Meanwhile, the mycotoxin-producing potential of the isolates was studied by liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS A total of 126 fungi were identified from the surface of samples by morphology and ITS sequencing, with Aspergillus and Penicillium genera as the predominant contaminants. The mycotoxin-producing potential analysis showed that 6 of 8 A. versicolor isolates could produce sterigmatocystin. All 3 A. aculeatus isolates produced ochratoxin A, but only 1 of 3 A. flavus strains produced aflatoxins B1 and B2 without G1 and G2. Although the sample contamination ratios were high (≥95.6%), there was no significant difference (χ2 = 1.05, P = 1.0) among the samples from 3 regions, which demonstrates the prevalent fungal contamination in the herbal medicines. CONCLUSION The prevalent contamination phenomenon of fungi and high potential risk of sterigmatocystin and ochratoxin A were observed in 45 medicinal herbs collected from China.
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Affiliation(s)
- Run-sheng Zheng
- Research Centre of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wen-li Wang
- Research Centre of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jing Tan
- Research Centre of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Hui Xu
- Research Centre of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Ruo-ting Zhan
- Research Centre of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wei-wen Chen
- Research Centre of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou, China
- Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education, Guangzhou University of Chinese Medicine, Guangzhou, China
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12
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Suzuki T, Iwahashi Y. Addition of Carbon to the Culture Medium Improves the Detection Efficiency of Aflatoxin Synthetic Fungi. Toxins (Basel) 2016; 8:toxins8110338. [PMID: 27854283 PMCID: PMC5127134 DOI: 10.3390/toxins8110338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 11/11/2016] [Indexed: 01/24/2023] Open
Abstract
Aflatoxin (AF) is a harmful secondary metabolite that is synthesized by the Aspergillus species. Although AF detection techniques have been developed, techniques for detection of AF synthetic fungi are still required. Techniques such as plate culture methods are continually being modified for this purpose. However, plate culture methods require refinement because they suffer from several issues. In this study, activated charcoal powder (carbon) was added to a culture medium containing cyclodextrin (CD) to enhance the contrast of fluorescence and improve the detection efficiency for AF synthetic fungi. Two culture media, potato dextrose agar and yeast extract sucrose agar, were investigated using both plate and liquid cultures. The final concentrations of CD and carbon in the media were 3 mg/mL and 0.3 mg/mL, respectively. Addition of carbon improved the visibility of fluorescence by attenuating approximately 30% of light scattering. Several fungi that could not be detected with only CD in the medium were detected with carbon addition. The carbon also facilitated fungal growth in the potato dextrose liquid medium. The results suggest that addition of carbon to media can enhance the observation of AF-derived fluorescence.
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Affiliation(s)
- Tadahiro Suzuki
- Division of Food Biotechnology, Food Research Institute, NARO, 2-1-12 Kannon-dai, Tsukuba, Ibaraki 305-8642, Japan.
| | - Yumiko Iwahashi
- Division of Food Safety, Food Research Institute, NARO, 2-1-12 Kannon-dai, Tsukuba, Ibaraki 305-8642, Japan.
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13
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Characterization of soybean fermented by aflatoxin non-producing Aspergillus oryzae and γ-aminobutyric acid producing Lactobacillus brevis. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s13765-014-4227-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Reduction of biogenic amines and aflatoxins in Doenjang samples fermented with various Meju as starter cultures. Food Control 2014. [DOI: 10.1016/j.foodcont.2014.02.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Liu P, Li B, Yin R, Weng Q, Chen Q. Development and evaluation of ITS- and aflP-based LAMP assays for rapid detection of Aspergillus flavus in food samples. Can J Microbiol 2014; 60:579-84. [PMID: 25126831 DOI: 10.1139/cjm-2014-0202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aspergillus flavus is a common filamentous fungus that produces aflatoxins and presents a major threat to agriculture and human health. Previous studies focused mainly on the detection of A. flavus or aflatoxin separately. Here, we developed internal transcribed spacer (ITS)- and aflP-based rapid detection of A. flavus in food samples using the loop-mediated isothermal amplification (LAMP) method. The ITS1-5.8S-ITS2 rDNA region of A. flavus and the aflatoxin-encoding gene aflP were used as target regions. The detection limits of A. flavus and aflP were 10 fg and 1 pg pure DNA, respectively, which allows aflatoxin-contaminated samples to be differentiated from infected samples and reduces false-negative or false-positive results. For specificity testing, DNA extracted from 7 A. flavus, 5 different Aspergillus spp., and 21 other fungi were used, and our results showed that A. flavus strains are detected by ITS-based detection and aflatoxigenic A. flavus strains are detected by aflP-based detection. Furthermore, the ITS- and aflP-based LAMP assays were used for detection analysis of DNA from food samples artificially and naturally contaminated with A. flavus. Our results showed that the detection rate of A. flavus based on the multi-ITS-based LAMP detection is 100% and that the aflatoxigenic strains in all A. flavus are detected by the aflP-based LAMP assay. The LAMP protocol described in our study represents a rapid and highly specific and sensitive diagnostic method for A. flavus detection, which can be used as a diagnostic tool that simplifies A. flavus monitoring and guarantees the quality and safety of foods.
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Affiliation(s)
- Peiqing Liu
- Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou 350003, People's Republic of China
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16
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Kim NY, Lee JH, Lee I, Ji GE. An evaluation of aflatoxin and cyclopiazonic acid production in Aspergillus oryzae. J Food Prot 2014; 77:1010-6. [PMID: 24853527 DOI: 10.4315/0362-028x.jfp-13-448] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To date, edible fungi such as Aspergillus flavus var. oryzae (A. oryzae) has been considered as safe. However, some strains can produce mycotoxins. Thus, the biosynthetic ability to produce mycotoxins should be reevaluated to determine the safety of edible fungi. We analyzed the production of aflatoxins and cyclopiazonic acid (CPA) from edible fungi such as A. oryzae isolated from various Korean foods using multiplex PCR, enzyme-linked immunosorbent assay, and high-performance liquid chromatography (HPLC). In the multiplex PCR analysis of aflatoxin biosynthetic genes omtB, aflR, ver-1, and omtA, 5 of 19 Aspergillus strains produced all PCR products. Among them, aflatoxin B1 and aflatoxin B2 were detected from only A. flavus KACC 41403 by HPLC. Aflatoxins were not detected from the other four strains that produced all positive PCR bands. Aflatoxin also was not detected from 12 strains that had PCR patterns without aflR or ver-1 and from 2 strains that did not produce any of the expected PCR products. Only the seven A. oryzae strains that produced all of the positive PCR bands including the CPA biosynthetic genes maoA, dmaT, and pks-nrps produced CPA. CPA and aflatoxin production must be evaluated before A. oryzae strains are used for the development of fermented foods.
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Affiliation(s)
- Nam Yeun Kim
- Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul 152-742, Republic of Korea
| | - Jin Hee Lee
- Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seongbuk-gu, Seoul 136-702, Republic of Korea
| | - Inhyung Lee
- Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seongbuk-gu, Seoul 136-702, Republic of Korea
| | - Geun Eog Ji
- Department of Food and Nutrition, Research Institute of Human Ecology, Seoul National University, Seoul 152-742, Republic of Korea, Research Institute; Bifido, Inc., Gangwon-do, Seoul 250-804, Republic of Korea.
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Ok HE, Kim DM, Kim D, Chung SH, Chung MS, Park KH, Chun HS. Mycobiota and natural occurrence of aflatoxin, deoxynivalenol, nivalenol and zearalenone in rice freshly harvested in South Korea. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.09.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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The proportion of non-aflatoxigenic strains of the Aspergillus flavus/oryzae complex from meju by analyses of the aflatoxin biosynthetic genes. J Microbiol 2013; 51:766-72. [PMID: 24385353 DOI: 10.1007/s12275-013-3128-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 07/04/2013] [Indexed: 10/25/2022]
Abstract
Strains of the Aspergillus flavus/oryzae complex are frequently isolated from meju, a fermented soybean product, that is used as the starting material for ganjang (soy sauce) and doenjang (soybean paste) production. In this study, we examined the aflatoxin producing capacity of A. flavus/oryzae strains isolated from meju. 192 strains of A. flavus/oryzae were isolated from more than 100 meju samples collected from diverse regions of Korea from 2008 to 2011, and the norB-cypA, omtA, and aflR genes in the aflatoxin biosynthesis gene cluster were analyzed. We found that 178 strains (92.7%) belonged to non-aflatoxigenic group (Type I of norB-cypA, IB-L-B-, IC-AO, or IA-L-B- of omtA, and AO type of aflR), and 14 strains (7.3%) belonged to aflatoxin-producible group (Type II of norB-cypA, IC-L-B+/B- or IC-L-B+ of omtA, and AF type of aflR). Only 7 strains (3.6%) in the aflatoxin-producible group produced aflatoxins on Czapek yeast-extract medium. The aflatoxin-producing capability of A. flavus/oryzae strains from other sources in Korea were also investigated, and 92.9% (52/56) strains from air, 93.9% (31/33) strains from rice straw, 91.7% (11/12) strains from soybean, 81.3% (13/16) strains from corn, 82% (41/50) strains from peanut, and 73.2% (41/56) strains from arable soil were included in the non-aflatoxigenic group. The proportion of non-aflatoxigenicity of meju strains was similar to that of strains from soybean, air and rice straw, all of which have an effect on the fermentation of meju. The data suggest that meju does not have a preference for non-aflatoxigenic or aflatoxin-producible strains of A. flavus/oryzae from the environment of meju. The non-aflatoxigenic meju strains are proposed to be named A. oryzae, while the meju strains that can produce aflatoxins should be referred to A. flavus in this study.
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