Natural occurrence of aflatoxins in Korean meju

Citizens protein project: A self-funded, transparent, and concerning report on analysis of popular protein supplements sold in the Indian market

Protein powders, including those containing herbal and dietary supplements such as vitamins, minerals, and other natural or synthetic ingredients, can be associated with hepatotoxicity. Protein supplements are often mislabeled and deceptive in their contents. In this self-funded transparent study, we extensively analyzed popular protein supplements in India to identify potential hepatotoxic substances based on industrial standards. All products underwent extensive analysis, including total protein content, fungal aflatoxin detection, pesticide residue estimation, heavy metal quantification, steroid detection, and complete organic and inorganic profiling, according to industry standards. Most protein supplements did not meet the labeled and advertised protein content, while certain brands surpassed the stated levels, raising concerns about potential "protein/amino-spiking." In addition, the major brands contained detectable fungal toxins and pesticide residues. Furthermore, many major formulations contained harmful heavy metals such as lead and arsenic, and some featured hepatoxic herbal extracts, particularly green tea extract, turmeric, Garcinia cambogia, and Ashwagandha. Indian-made products were inferior to those manufactured by multinational companies. The presence of various potentially toxic compounds, such as cycloheptatriene, benzene derivatives, toluene, and isopropyl alcohol, within a nonstandardized and unregulated diverse ingredient mix added to the overall concern. We demonstrate that the protein-based herbal and dietary supplement industry requires stringent scrutiny, regulation, and basic safety studies before being marketed. Manufacturers must consider reducing "ingredient complexities" of their protein powders to prevent adverse interactions between herbal and nonherbal components in consumers. Manufacturers must avoid using known toxic ingredients to reduce the avoidable disease burden within the public community.

Alleviation of Metabolic Disturbance by Substituting Kanjang High in Bacillus for Salt through Modulation of Gut Microbiota in Estrogen-Deficient Rats

A high salt intake may exacerbate menopausal symptoms and substituting for different types of traditionally made kanjang (TMK; soy sauce) may prevent it. This study examined whether substituting salt with lyophilized TMK containing low and high Bacillus and biogenic amines in a high-fat diet might modulate the menopausal symptoms and the energy, glucose, and lipid metabolism in ovariectomized (OVX) rats. They were categorized into salt (Control), TMK with high Bacillus and low biogenic amines (HBLB), TMK with high Bacillus and high biogenic amines (HBHB), TMK with low Bacillus and low biogenic amines (LBLB), and TMK with low Bacillus and high biogenic amines (LBHB). Sham-operated rats consumed the same diet as the Control. HBLB, HBHB, and LBHB prevented increased tail skin temperature compared to the Control. HBHB and HBLB partially inhibited the increased weight gain and abdominal fat mass by reducing the food efficiency without changing the serum 17β-estradiol concentrations. Serum glucose and insulin concentrations and the insulin resistance index by the homeostatic model assessment for insulin resistance showed a positive association for weight gain. HBLB and HBHB decreased the serum malondialdehyde and tumor-necrosis factor-α levels. Hepatic triglyceride storage was lower in all TMK groups than in the Control, while hepatic glycogen accumulation was higher in the HBLB, HBHB, and LBHB groups than in the Control and LBLB groups. Accordingly, the mRNA expression of peroxisome proliferator-activated receptors-γ(PPAR-γ) was higher in the HBLB and HBHB groups compared to the Control, and that of fatty acid synthase was opposite to PPAR-γ expression. However, HBLB and HBHB improved dyslipidemia and insulin resistance compared to the Control, but their improvement did not reach that of the Normal-control. The acetic acid concentrations in the portal vein were lower in the LBLB than in the Control, while the butyric acid contents were higher in the LBHB and HBLB groups than in the Control. HBHB, HBLB, and LBHB elevated Akkermansia and Lactobacillus, and HBLB and LBLB increased Bacteroides and Ruminococcus compared to the Control. Polycyclic aromatic hydrocarbon degradation, bile acid synthesis, and unsaturated fatty acid biosynthesis were significantly higher in the HBLB group than in the Control group. In conclusion, substituting salts to TMK with a high Bacillus content regardless of the bioamine contents partially improved the menopausal symptoms and metabolic disturbance in estrogen-deficient animals.

Aspergillus derived mycotoxins in food and the environment: Prevalence, detection, and toxicity

Aspergillus species are the paramount ubiquitous fungi that contaminate various food substrates and produce biochemicals known as mycotoxins. Aflatoxins (AFTs), ochratoxin A (OTA), patulin (PAT), citrinin (CIT), aflatrem (AT), secalonic acids (SA), cyclopiazonic acid (CPA), terrein (TR), sterigmatocystin (ST) and gliotoxin (GT), and other toxins produced by species of Aspergillus plays a major role in food and human health. Mycotoxins exhibited wide range of toxicity to the humans and animal models even at nanomolar (nM) concentration. Consumption of detrimental mycotoxins adulterated foodstuffs affects human and animal health even trace amounts. Bioaerosols consisting of spores and hyphal fragments are active elicitors of bronchial irritation and allergy, and challenging to the public health. Aspergillus is the furthermost predominant environmental contaminant unswervingly defile lives with a 40-90 % mortality risk in patients with conceded immunity. Genomics, proteomics, transcriptomics, and metabolomics approaches useful for mycotoxins' detection which are expensive. Antibody based detection of toxins chemotypes may result in cross-reactivity and uncertainty. Aptamers (APT) are single stranded DNA (ssDNA/RNA), are specifically binds to the target molecules can be generated by systematic evolution of ligands through exponential enrichment (SELEX). APT are fast, sensitive, simple, in-expensive, and field-deployable rapid point of care (POC) detection of toxins, and a better alternative to antibodies.

Detection of Total Aflatoxins in Groundnut and Soybean Samples in Yemen Using Enzyme-Linked Immunosorbent Assay

Aflatoxins are fungal toxins that have mutagenic and carcinogenic effects, especially hepatocellular carcinoma effect. This work aimed to investigate the presence of aflatoxins in groundnuts and soybeans that are consumed in Yemen. The samples were collected from three different regions in Yemen (Sana’a, al-Hodeida, and Aden), and they were divided into two groups. The concentration of total aflatoxins was analyzed by enzyme-linked immunosorbent assay (ELISA). Aflatoxins were determined in 89 groundnut and 65 soybean samples. The results showed that 85.39% (76/89) of groundnut and 72.3% (45/65) of soybean samples were contaminated with aflatoxins. In addition, in 49.44% and 27.6% of the groundnut and soybean samples, total aflatoxins exceed the acceptable level of European Commission (4 μg/kg), while in only 6.2% of soybean samples and 22.47% of groundnut samples, total aflatoxins were beyond the maximum limit of FDA/Yemen standards (20 μg/kg). The results showed that the aflatoxin contamination in the groundnut and soybean samples may be considered a significant risk for public health. The present study is the first to report the data on the presence of aflatoxins in groundnut and soybean samples in Yemen.

Reduction of aflatoxins (B₁, B₂, G₁, and G₂) in soybean-based model systems

The effects of chemical, physical, and cooking treatments on the reduction of aflatoxin B1 (AFB1), B2, G1, and G2 in soybean matrix were investigated. A HPLC-FLD with a Kobra cell system was used for the quantitative analysis of aflatoxins (AFs). To decrease the level of AFs during the soaking process, the contaminated soybeans were submerged in organic acid solutions. The reduction rates of AFB1 in 1.0N citric acid, lactic acid, succinic acid, and tartaric acid for 18h were 94.1%, 92.7%, 62.0%, and 95.1%, respectively. In the case of pH and autoclave treatment, the level of AFB1 was significantly decreased during autoclaving process at pH 7.4, 9.0, and 11.1, compared with the non-autoclaved samples (p<0.05). In the case of physical treatment, the heating process at 100 and 150°C for 90min significantly decreased the level of AFB1 by 41.9% and 81.2%, respectively (p<0.05). The reduction rate of AFB1 after cooking was 97.9% for soybean milk and 33.6% for steamed soybeans.

The proportion of non-aflatoxigenic strains of the Aspergillus flavus/oryzae complex from meju by analyses of the aflatoxin biosynthetic genes

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.

Identification and Characterization of Eurotium rubrum Isolated from Meju in Korea

We isolated and identified a strain of Eurotium rubrum from Meju that has not been reported in Korea. This fungus is yellowish brown; reverse dark brown on CYA and PDA while yellow on 2% MEA at 25℃. Cleistothecia are first bright yellow and gradually turned brown. Mycerial growth on CYA attained a diameter of 30 mm at 20℃, 37 mm at 25℃ and 32 mm at 30℃ after 15 days. The isolate grew slower on 2% MEA (< 20 mm 15 days at 25℃) compared to CYA and PDA (< 40 mm 15 days at 25℃). Cleistothecia are superficial, yellow to light brown, globose to subglobose, 40~75 µm in diameter. Asci are 8-spored and globose to subglobose 8~11 µm. Ascospores are disciform, 4.0~5.0 µm in length and 4.2~4.5 µm in width. Conidia are ovate or bacillar, finely roughened to densely spinulose, 4.6~6.0 µm in length and 3.0~4.3 µm in width. Compared to known Eurotium rubrum, the Korean isolate showed 99% sequence similarity in ITS rDNA (554 bp) and calmodulin (750 bp) gene and 100% in β-tubulin (1016 bp) gene. The E. rubrum isolate also had weak β-glucosidase and protease activities.

Identification and toxigenic potential of the industrially important fungi, Aspergillus oryzae and Aspergillus sojae

Mold strains belonging to the species Aspergillus oryzae and Aspergillus sojae are highly valued as koji molds in the traditional preparation of fermented foods, such as miso, sake, and shoyu, and as protein production hosts in modern industrial processes. A. oryzae and A. sojae are relatives of the wild molds Aspergillus flavus and Aspergillus parasiticus. All four species are classified to the A. flavus group. Strains of the A. flavus group are characterized by a high degree of morphological similarity. Koji mold species are generally perceived of as being nontoxigenic, whereas wild molds are associated with the carcinogenic aflatoxins. Thus, reliable identification of individual strains is very important for application purposes. This review considers the pheno- and genotypic markers used in the classification of A. flavus group strains and specifically in the identification of A. oryzae and A. sojae strains. Separation of A. oryzae and A. sojae from A. flavus and A. parasiticus, respectively, is inconsistent, and both morphologic and molecular evidence support conspecificity. The high degree of identity is reflected by the divergent identification of reference cultures maintained in culture collections. As close relatives of aflatoxin-producing wild molds, koji molds possess an aflatoxin gene homolog cluster. Some strains identified as A. oryzae and A. sojae have been implicated in aflatoxin production. Identification of a strain as A. oryzae or A. sojae is no guarantee of its inability to produce aflatoxins or other toxic metabolites. Toxigenic potential must be determined specifically for individual strains. The species taxa, A. oryzae and A. sojae, are currently conserved by societal issues.

Estimation of the daily exposure of Koreans to aflatoxin B1 through food consumption

A survey for aflatoxin B(1) (AFB(1)) was conducted on 88 food-grade rice samples randomly collected during July and August 2002 in Seoul, Korea. The presence of AFB(1) was determined by enzyme-linked immunosorbent assay, and the positive samples from enzyme-linked immunosorbent assay were confirmed using high-performance liquid chromatography. Besides this, from the surveying data from the literature published since 1997, the intake of AFB(1) from food in Korea was calculated and compared with the provisional maximum tolerable daily intakes. Naturally occurring AFB(1) was found in 5/88 (6%) samples of rice with an average of 4.8 ng g(-1). A calculated probable daily intake of AFB(1) for Koreans fell into the range 1.19-5.79 ng kg(-1) bw day(-1), hence exceeding the estimated provisional maximum tolerable daily intakes. In conclusion, the exposure of Koreans to AFB(1) could bring about health concerns. This is the first report discovering that rice is the major contributor to the dietary intake of AFB(1) in Korea.

Natural co-occurrence of aflatoxin B1, fumonisin B1 and ochratoxin A in barley and corn foods from Korea

A survey for aflatoxin B1 (AFB1), fumonisin B1 and ochratoxin A (OTA) was conducted on 127 samples that included 30 food-grade barley, 32 barley foods, 18 food-grade corn and 47 corn foods, randomly collected during 1998-99 in Seoul, Korea. The presence of mycotoxins was analysed by direct competitive enzyme-linked immunosorbent assay (ELISA), and most of the positive samples from ELISA were confirmed using high-performance liquid chromatography (HPLC). Recoveries of AFB1 and OTA spiked at 10 ng g(-1) and FB1 spiked at 50 ng g(-1) were 106, 87 and 105% by ELISA, whereas those by HPLC were 80, 79 and 84%, respectively. Detection limits by ELISA for AFB1, FB1 and OTA were 1, 5 and 5 ng g(-1), and those by HPLC were 0.6, 35 and 1 ng g(-1). Naturally occurring AFB1, FB1 and OTA were found in 4/32 (12%), 2/32(6%) and 4/32 (12%) samples of barley foods with an average of 26, 16 and 9 ng g(-1), respectively. AFB1 and FB1 in corn foods were detected in 4/47 (8%) and 9/47 (19%) samples with the average being 20 and 74 ng g(-1), while no OTA was found in any corn foods samples. No AFB1, FB1 or OTA was detected in any of food-grade barley and corn samples. This is the first report on the natural co-occurrence of AFB1 and FB1 in barley and corn foods as well as on surveillance of OTA in Korea.