Worldwide occurrence of mycotoxins in rice

Cancer- and non-cancer risk prioritization of regulated mycotoxins in Taiwan: Insights from the 2018-2022 official Mycotoxin monitoring survey

The prevalence and residue levels of mycotoxins in food have emerged as a global public health concern, exacerbated by climate change. Despite routine monitoring of mycotoxin residues in foodstuffs by health agencies, comprehensive exposure assessments remain limited due to insufficient food consumption data and complex food classification systems. This study employed the Stochastic Human Exposure and Dose Simulation High-Throughput (SHEDS-HT) model, adapted for the Taiwanese population with National Food Consumption Database (NFCD), to estimate aggregate dietary exposure to six major mycotoxins: aflatoxin B1, ochratoxin A, zearalenone, fumonisin B1, deoxynivalenol, and citrinin. Using Margin of Exposure (MoE) analysis, citrinin was identified as the non-carcinogenic priority mycotoxin, with infants and children being the most vulnerable group due to their higher intake of rice-based products per unit body weight. Additionally, 2.5% and 2.4% of the population exceeded the (provisional) tolerable daily intake (pTDI) for ochratoxin A and aflatoxin B1, respectively, with notable detection in candy, spices, sugar, and peanut-based products. For cancer risk characterization, aflatoxin B1 and ochratoxin A demonstrated MoE values below the critical safety threshold (10,000), indicating potential health risks. This study highlights the urgent need for coordinated surveillance and emphasizes the importance of biomonitoring approaches to better characterize total mycotoxin exposure in Taiwan, providing valuable insights for evidence-based risk management and regulatory strategies.

Diversity of Mycotoxins in Stored Paddy Rice: Contamination Patterns in the Mekong Delta, Vietnam

Rice (Oryza sativa L.) is the most important food in Vietnam. However, rice is often lost in post-harvest due to fungal growth and mycotoxins contamination. This study aimed to evaluate mycotoxin contamination in stored paddy rice collected in 2018, 2019, and 2022 in six provinces in Mekong Delta, Vietnam, using LC-MS/MS. The results revealed that 47% of the samples were contaminated with 12 types of mycotoxins. The prevalence of these mycotoxins was 30% (ZEN), 10% (FUS/MON), 6% (BEA/AFB2), 2-4% (AFG1, AFB1, AFG2), 2% (FB1), and 1% (OTA/AME/ENB). Among the provinces, stored paddy rice from Kien Giang had the highest contamination, followed by Ben Tre, Long An, An Giang, Dong Thap, and Can Tho. Remarkably, paddy rice collected in 2022 was usually contaminated with emerging mycotoxins with a higher incidence of co-occurrence ranging from 2-6% of the samples. Additionally, five stored paddy rice samples were contaminated with levels of AFB1, OTA, and ZEN exceeding Vietnamese regulatory limits for unprocessed rice. Our findings provide valuable insights into mycotoxin contamination across different years and growing regions in the Mekong Delta, Vietnam. This study could give essential information to stakeholders, including policy-makers or food safety authorities, etc., to inform strategies to mitigate these toxins in the near future and underscores the importance of monitoring rice production.

Development of a high-throughput UHPLC-MS/MS method for the analysis of Fusarium and Alternaria toxins in cereals and cereal-based food

A QuEChERS (quick, easy, cheap, effective, rugged, and safe)-based multi-mycotoxin method was developed, analyzing 24 (17 free and 7 modified) Alternaria and Fusarium toxins in cereals via ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A modified QuEChERS approach was optimized for sample preparation. Quantification was conducted using a combination of stable isotope dilution analysis (SIDA) for nine toxins and matrix-matched calibration for ten toxins. Quantification via a structurally similar internal standard was conducted for four analytes. Alternariol-9-sulfate (AOH-9-S) was measured qualitatively. Limits of detection (LODs) were between 0.004 µg/kg for enniatin A1 (ENN A1) and 3.16 µg/kg for nivalenol (NIV), while the limits of quantification were between 0.013 and 11.8 µg/kg, respectively. The method was successfully applied to analyze 136 cereals and cereal-based foods, including 28 cereal-based infant food products. The analyzed samples were frequently contaminated with Alternaria toxins, proving their ubiquitous occurrence. Interestingly, in many of those samples, some modified Alternaria toxins occurred, mainly alternariol-3-sulfate (AOH-3-S) and alternariol monomethyl ether-3-sulfate (AME-3-S), thus highlighting the importance of including modified mycotoxins in the routine analysis as they may significantly add to the total exposure of their parent toxins. Over 95% of the analyzed samples were contaminated with at least one toxin. Despite the general contamination, no maximum or indicative levels were exceeded.

A diverse Fusarium community is responsible for contamination of rice with a variety of Fusarium toxins

Rice plays an important role in the daily diet in China and therefore its quality and safety have been of great concern. However, few systematic studies have investigated Fusarium community and toxins in rice grains. Here, we collected 1381 rice samples from Jiangsu Province in eastern China and found a higher frequency of zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FBs), and beauvericin (BEA). The positive samples were individually contaminated with a minimum of one and a maximum of ten toxins. Fusarium was isolated and identified as the major fungus, which exhibited temporal and geographical distribution. The most prevalent species complexes within this genus were Fusarium incarnatum-equiseti species complex (FIESC), Fusarium fujikuroi species complex (FFSC), and Fusarium sambucinum species complex (FSAMSC). Nevertheless, the amplicon sequence analysis revealed a low relative abundance of Fusarium in the rice panicles, and the fungal community exhibited an irregular change along with the symptom's emergence. In vitro toxigenic profiles of Fusarium strains showed significant complexity and specificity depending on the type and content. FIESC strains were non-pathogenic to wheat heads and weakly pathogenic to maize ears, respectively, accumulating lower amounts of toxins than F. asiaticum and F. fujikuroi. There was no significant variation in the ability to cause panicle blight in rice among the various species tested. Our study provides detailed information about the contamination of Fusarium toxins and community in rice after harvest. This information is valuable for understanding the relationship between Fusarium and rice and for developing effective control strategies.

Citrinin disrupts microtubule assembly in cardiac cells: Impact on mitochondrial organization and function

Citrinin (CTN) is a mycotoxin commonly present in various foods and feeds worldwide, as well as dietary supplements in Asian countries, but the risks and cellular mechanisms associated with its cardiotoxicity remains unclear. In this study, RNA-seq analysis of CTN-treated H9c2 cardiac cells demonstrated significant perturbations in pathways related to microtubule cytoskeleton and mitochondrial network organization. CTN disrupted microtubule polymerization and downregulated mRNA levels of microtubule-assembling genes, Map2 and Tpx2, in H9c2 cardiac cells. Additionally, CTN interfered with the distribution of mitochondrial network along the microtubules, leading to the accumulation of dysfunctional mitochondria characterized by elevated superoxide levels and reduced membrane potential. This disruption also caused the buildup of lysosomes and ubiquitinated proteins, which hindered waste clearance in microtubule-disassembled H9c2 cells. Molecular docking analysis indicated that CTN could bind to the colchicine binding site on β-tubulin, thereby mimicking the microtubule-disrupting effect of colchicine. This study provides morphological, transcriptomic, and mechanistic evidence to elucidate the cardiotoxic mechanisms of CTN, which involve the dysregulated microtubule network, subsequent mitochondrial mislocalization, and impaired proteolysis of damaged proteins/organelles in cardiac cells. Our findings may enhance the fundamental understanding and facilitate future risk assessment of CTN.

Immunochromatographic Strip Based on Tetrahedral DNA Immunoprobe for the Detection of Aflatoxin B1 in Rice Bran Oil

Aflatoxin B1 (AFB1), a widespread contaminant in food and feeds, poses a threat to the health of animals and humans. Consequently, it is significant to develop a rapid, precise and highly sensitive analytical method for the detection of AFB1. Herein, we developed an immunochromatographic strip (ICS) based on a tetrahedral DNA (TDN) immunoprobe for AFB1 determination in rice bran oil. Three sizes of TDN immunoprobes (AuNP-TDN13bp-mAb, AuNP-TDN17bp-mAb, AuNP-TDN26bp-mAb) were constructed, and the performance of these three immunoprobes, including the effective antibody labeling density and immunoaffinity, was measured and compared with that of the immunoprobe (AuNP-mAb) developed using the physical adsorption method. Subsequently, the optimal TDN immunoprobe, namely AuNP-TDN13bp-mAb, was selected to prepare the immunochromatographic strip (ICS) for the qualitative and quantitative detection of AFB1 in rice bran oil. The visual limits of detection (vLODs) of the ICS based on AuNP-TDN13bp-mAb and AuNP-mAb were 0.2 ng/mL and 2 ng/mL, with scanning quantitative limits (sLOQs) of 0.13 ng/mL and 1.4 ng/mL, respectively. The ICS demonstrated a wide linear range from 0.02 ng/mL to 0.5 ng/mL, with good specificity, accuracy, precision, repeatability, and stability. Moreover, a high consistency was observed between the constructed ICS and ultra-high-performance liquid chromatography (UPLC) in the quantification of AFB1. The results indicated that the introduction of TDN was beneficial for promoting efficient antibody labeling, protecting the bioactivity of immunoprobes, and increasing the sensitivity of detection, which would provide new perspectives for the achievement of the highly sensitive detection of mycotoxins.

The Questionable Quality Profile of Food Supplements: The Case of Red Yeast Rice Marketed Products

Food supplements (FS) containing red yeast rice (RYR) are largely employed to reduce lipid levels in the blood. The main ingredient responsible for biological activity is monacolin K (MoK), a natural compound with the same chemical structure as lovastatin. Concentrated sources of substances with a nutritional or physiological effect are marketed in "dose" form as food supplements (FS). The quality profile of the "dosage form" of FS is not defined in Europe, whereas some quality criteria are provided in the United States. Here, we evaluate the quality profile of FS containing RYR marketed in Italy as tablets or capsules running two tests reported in The European Pharmacopoeia 11 Ed. and very close to those reported in the USP. The results highlighted variations in dosage form uniformity (mass and MoK content) compliant with The European Pharmacopoeia 11 Ed. specifications, whereas the time needed for disintegrating tablets was longer for 44% of the tested samples. The bioaccessibility of MoK was also investigated to obtain valuable data on the biological behaviour of the tested FS. In addition, a method for citrinin (CIT) determination was optimized and applied to real samples. None of the analyzed samples demonstrated CIT contamination (LOQ set at 6.25 ng/mL). Considering the widespread use of FS, our data suggest that greater attention should be paid by fabricants and regulatory authorities to ensure the quality profile and the safe consumption of marketed products.

Mycotoxins in Rice Correlate with Other Contaminants? A Pilot Study of the Portuguese Scenario and Human Risk Assessment

Rice is the second most important cereal crop and is vital for the diet of billions of people. However, its consumption can increase human exposure to chemical contaminants, namely mycotoxins and metalloids. Our goal was to evaluate the occurrence and human exposure of aflatoxin B1 (AFB1), ochratoxin A (OTA), zearalenone (ZEN), and inorganic arsenic (InAs) in 36 rice samples produced and commercialized in Portugal and evaluate their correlation. The analysis of mycotoxins involved ELISA, with limits of detection (LODs) of 0.8, 1 and 1.75 μg kg^-1 for OTA, AFB1, and ZEN, respectively. InAs analysis was carried out by inductively coupled plasma mass spectrometry (ICP-MS; LOD = 3.3 μg kg^-1). No sample showed contamination by OTA. AFB1 was present in 2 (4.8%) samples (1.96 and 2.20 μg kg^-1), doubling the European maximum permitted level (MPL). Concerning ZEN, 88.89% of the rice samples presented levels above the LOD up to 14.25 µg kg^-1 (average of 2.75 µg kg^-1). Regarding InAs, every sample presented concentration values above the LOD up to 100.0 µg kg^-1 (average of 35.3 µg kg^-1), although none surpassed the MPL (200 µg kg^-1). No correlation was observed between mycotoxins and InAs contamination. As for human exposure, only AFB1 surpassed the provisional maximum tolerable daily intake. Children were recognized as the most susceptible group.

Storage Fungi and Mycotoxins Associated with Rice Samples Commercialized in Thailand

The study focused on the examination of the different fungal species isolated from commercial rice samples, applying conventional culture techniques, as well as different molecular and phylogenic analyses to confirm phenotypic identification. Additionally, the mycotoxin production and contamination were analyzed using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS). In total, 40 rice samples were obtained covering rice berry, red jasmine rice, brown rice, germinated brown rice, and white rice. The blotting paper technique applied on the 5 different types of rice samples detected 4285 seed-borne fungal infections (26.8%) for 16,000 rice grains. Gross morphological data revealed that 19 fungal isolates belonged to the genera Penicillium/Talaromyces (18 of 90 isolates; 20%) and Aspergillus (72 of 90 isolates; 80%). To check their morphologies, molecular data (fungal sequence-based BLAST results and a phylogenetic tree of the combined ITS, BenA, CaM, and RPB2 datasets) confirmed the initial classification. The phylogenic analysis revealed that eight isolates belonged to P. citrinum and, additionally, one isolate each belonged to P. chermesinum, A. niger, A. fumigatus, and A. tubingensis. Furthermore, four isolates of T. pinophilus and one isolate of each taxon were identified as Talaromyces (T. radicus, T. purpureogenum, and T. islandicus). The results showed that A. niger and T. pinophilus were two commonly occurring fungal species in rice samples. After subculturing, ochratoxin A (OTA), generated by T. pinophilus code W3-04, was discovered using LC-MS/MS. In addition, the Fusarium toxin beauvericin was detected in one of the samples. Aflatoxin B1 or other mycotoxins, such as citrinin, trichothecenes, and fumonisins, were detected. These preliminary findings should provide valuable guidance for hazard analysis critical control point concepts used by commercial food suppliers, including the analysis of multiple mycotoxins. Based on the current findings, mycotoxin analyses should focus on A. niger toxins, including OTA and metabolites of T. pinophilus (recently considered a producer of emerging mycotoxins) to exclude health hazards related to the traditionally high consumption of rice by Thai people.

Exposure Assessment of Aflatoxin B1 through Consumption of Rice in the United Arab Emirates

Rice is one of the most consumed staple foods worldwide and a major part of the diet for half of the global population. Being primarily cultivated in countries with warm and humid environments increases rice's susceptibility for mycotoxins contamination, especially the hepatotoxic and carcinogenic aflatoxin B1 (AFB1). Since no study was published before on the exposure to AFB1 from consuming rice in the UAE, our study aims to assess the levels of AFB1 in rice marketed in the country and determine the estimated daily exposure of the population for this carcinogenic metabolite and its associated liver cancer risk. All white, brown, and parboiled rice brands available in the retail markets in the UAE were procured twice. Using an enzyme-linked immunosorbent assay (ELISA) method, AFB1 was detected in 48 out of 128 rice samples (38%). The average contamination ± standard deviation of AFB1 among positive samples (above the detection limit) was found to be 1.66 ± 0.89 μg/kg, ranging from 1 μg/kg (detection limit) to 4.69 μg/kg. The contamination level in all the samples was below the limit set by the Gulf Cooperation Council Standardization Organization (≤5 μg/kg), while 10 (20.8%) of the positive samples had a contamination level above the maximum limit set by the European Union (≥2 μg/kg). The moisture content in all the assessed samples was ≤14%. Furthermore, there was a significant difference in AFB1 between samples in both collections (p-value = 0.043). However, the rice type, grain size, packing country, packing season, country of origin, collection season, and packing to purchasing time had no significant effect on AFB1. The calculated mean daily exposure level of the Emirati population to AFB1 from consuming rice was 4.83 ng/kg.

Mycotoxin surveillance on wheats in Shandong province, China, reveals non-negligible probabilistic health risk of chronic gastrointestinal diseases posed by deoxynivalenol

Abnormal climate changes have resulted in over-precipitation in many regions. The occurrence and contamination levels of mycotoxins in crops and cereals have been elevated largely. From 2017 to 2019, we did investigation targeting 15 mycotoxins shown in the wheat samples collected from Shandong, a region suffering over-precipitation in China. We found that deoxynivalenol (DON) was the dominant mycotoxin contaminating wheats, with detection rates 304/340 in 2017 (89.41%), 303/330 in 2018 (91.82%), and 303/340 in 2019 (89.12%). The ranges of DON levels were < 4 to 580 μg/kg in 2017, < 4 to 3070 μg/kg in 2018, and < 4 to 1540 μg/kg in 2019. The exposure levels were highly correlated with local precipitation. Male exposure levels were generally higher than female's, with significant difference found in 2017 (1.89-fold, p = 0.023). Rural exposure levels were higher than that of cities but not statistically significant (1.41-fold, p = 0.13). Estimated daily intake (EDI) and margin of exposure (MoE) approaches revealed that 8 prefecture cities have probabilistically extra adverse health effects (vomiting or diarrhea) cases > 100 patients in 100,000 residents attributable to DON exposure. As a prominent wheat-growing area, Dezhou city reached ~ 300/100,000 extra cases while being considered as a major regional contributor to DON contamination. Our study suggests that more effort should be given to the prevention and control of DON contamination in major wheat-growing areas, particularly during heavy precipitation year. The mechanistic association between DON and chronic intestinal disorder/diseases should be further investigated.

Exposure to Ochratoxin A from Rice Consumption in Lebanon and United Arab Emirates: A Comparative Study

Our study aims to evaluate the ochratoxin A (OTA) in rice marketed in Lebanon and the United Arab Emirates (UAE), and to determine the exposure to OTA from rice consumption. All brands available in the market were collected twice (total number of collected samples: 105 and 127 in Lebanon and the UAE, respectively). Using ELISA, the OTA in 56 (53%) samples in Lebanon and 73 (58%) samples in the UAE were above the limit of quantification (0.8 μg/kg). The average concentrations of the positive samples ± standard deviations were 1.29 ± 0.32 and 1.40 ± 0.42 μg/kg in Lebanon and the UAE, respectively. Only one sample (1%) in Lebanon had a level at the borderline of the European Union (EU) limit, and two samples (1.6%) in the UAE had a level above the EU limit (5 μg/kg). The OTA in brown rice was higher than in white and parboiled rice for both countries, yet the difference was not significant. The packing season, packing country, and country of origin did not have any significant effects. The presence of a food safety certification resulted in lower OTA in the rice, but the difference was significant (p = 0.04) in the UAE only. Long grains had higher OTA than short grains, yet the difference was only significant in Lebanon (p = 0.046). The exposures were calculated as 1.27 ng/kg body weight/day in Lebanon and 1.42 ng/kg body weight/day in the UAE, and no health risk was observed for both the neoplastic and non-neoplastic effects.

Aflatoxin B1 in Rice: Effects of Storage Duration, Grain Type and Size, Production Site, and Season

ABSTRACT

Our study evaluated aflatoxin B1 (AFB1) levels in packed rice marketed in Lebanon and determined the exposure to this toxin from rice consumption. A total of 105 packed white, parboiled, and brown rice bags were collected. Enzyme-linked immunosorbent assay was used to measure AFB1. A comprehensive food frequency questionnaire was completed by 500 participants to determine patterns of rice consumption and, subsequently, the exposure levels to AFB1 from rice consumption in Lebanon. AFB1 was detected in all rice samples (100%). The average concentration ± standard deviation of AFB1 was 0.5 ± 0.3 μg/kg. Contamination ranged between 0.06 and 2.08 μg/kg. Moisture content in all rice samples was below the recommended percentage (14%). Only 1% of the samples had an AFB1 level above the European Union limit (2 μg/kg). Brown rice had a significantly higher AFB1 level than white and parboiled rice (P = 0.02), while a significant difference was found between both collections for the same brands (P = 0.016). Packing season, packing country, country of origin, presence of a food safety management certification, grain size, and time between packing and purchasing had no significant effect. Exposure to AFB1 from rice consumption in Lebanon was calculated as 0.1 to 2 ng/kg of body weight per day.

HIGHLIGHTS

The Effect of Monitoring System on Risk Assessment of Aflatoxins in Iran's Pistachio Nuts Exported to the E.U. During 2012 - 2018

Pistachio has high nutritional value and popularity. The susceptibility of pistachio to aflatoxin contamination caused establishing a monitoring system introduced and implemented by the Ministry of Health in Iran to ensure consumers' access to safe and hygienic pistachios. In this research, aflatoxin contamination level in all consignments (7298) exporting to E.U. was examined using HPLC with fluorescence detection after immunoaffinity column clean up from Nov 2012 to Oct 2018. The average recoveries ranged 78.6% - 97.6%, with a relative standard deviation for reproducibility below 8.5% and expanded uncertainty of aflatoxin B1 (AFB1) at spiked levels 1, 4, and 8 ng/g were 0.17, 0.57, 0.89 ng/g, respectively. The results showed that aflatoxin B1 and total (AFT) were detected in 1921 (23.4%) and 1927 cases (23.5%), with the mean values ranging from 2.18 - 4.6 ng/g and 2.8 - 5.1 ng/g during six consecutive years, respectively. Implementing an effective monitoring system for pistachio nuts could determine consignments contaminated with aflatoxins. Concerning AFB1, risk assessments recorded for dietary exposure dose, margin of exposure (MOE), Hazard Index (HI), estimated liver cancer risk, and cancer incidence attributable to dietary ranged 0.0132 - 0.1180 ng/kg.bw/day, 1441 - 12843, 0.21 - 1.84, 0.00071 - 0.00633 cases/10⁵ population/year, 0.02 - 0.2%, respectively. Identification and rejection of contaminated cargos lead to an increase in MOE (> 10000), and it also guarantees that pistachio consumption is safe from a toxicology point of view. Due to the monitoring system, the estimation of liver cancer incidence attributable to dietary AFB1 was reduced (≤ 0.02%). It indicates that the consumption of pistachio poses no health risk for Europeans and Iranians.

Mycotoxins in soil and environment

Mycotoxins are secondary metabolites produced by specific fungi that have harmful effects on animals and humans. Worldwide more than 300 different mycotoxins are already known, frequently with concentrations in harvest products exceeding acceptable limits. Nevertheless, although these compounds have extensively been studied in food and feed, only little is known about their occurrence and fate in soil and agro-environmental matrices, such as manure, sewage sludge, drainage water and sediments. Therefore, the aim of this review was to (i) resume available methods for quantifying mycotoxins in soil, (ii) describe the occurrence and quantities of mycotoxins in soil and related agro-environmental matrices, and (iii) discuss the environmental fate of these target compounds with specific focus on their leaching potential into groundwater. The safest and most reliable method for mycotoxin quantification relies on mass spectrometry, while the extraction method and solvent composition differ depending on the compound under investigation. Mycotoxin levels detected in soils to date were in the μg range, reaching maximum amounts of 72.1 μg kg^-1 for zearalenone, 32.1 μg kg^-1 for deoxynivalenol, 23.7 μg kg^-1 for ochratoxin A, 6.7 μg kg^-1 for nivalenol, and 5.5 μg kg^-1 for aflatoxin. Different compartments in the agroecosystem (cereals, corn, rice, water, manure, sewage sludge) each contained at least one mycotoxin. Mycotoxin retention in soils is controlled by texture, with significant adsorption of the compounds to clays but leaching potentials in sandy soils. We did not find any reports detecting mycotoxins in sediments, although there are increasing reports of mycotoxins in freshwater samples. Overall, it appears that soils and sediments are still underrepresented in research on potential environmental contamination with mycotoxins.

Reduced of mycotoxin levels in parboiled rice by using ozone and its effects on technological and chemical properties

Contamination of foods by mycotoxins is a reality. However, emerging technologies such as ozonization can be used to reduce the levels of these contaminants. Thus, the aim of this study was to evaluate the effects of using ozone at different period and application times during the soaking step of parboiling process. Samples were analyzed for qualitative and quantitative analysis of mycotoxins, swelling power and solubility, head rice yield, protein solubility, cooking time, texturometric profile, colorimetric profile and defective grains. The results showed tha parboiled rice grains treated with ozone present significant reduction of mycotoxins contamination, regardless of the time and period of application and the mycotoxin evaluated. Regardig to technological properties, the samples treated with ozone in the final 3 h and for 5 h of soaking presented higher head rice yield, luminosity and hardness, with decreases in cooking time, percentage of defective grains and soluble protein.

Citrinin Mycotoxin Contamination in Food and Feed: Impact on Agriculture, Human Health, and Detection and Management Strategies

Citrinin (CIT) is a mycotoxin produced by different species of Aspergillus, Penicillium, and Monascus. CIT can contaminate a wide range of foods and feeds at any time during the pre-harvest, harvest, and post-harvest stages. CIT can be usually found in beans, fruits, fruit and vegetable juices, herbs and spices, and dairy products, as well as red mold rice. CIT exerts nephrotoxic and genotoxic effects in both humans and animals, thereby raising concerns regarding the consumption of CIT-contaminated food and feed. Hence, to minimize the risk of CIT contamination in food and feed, understanding the incidence of CIT occurrence, its sources, and biosynthetic pathways could assist in the effective implementation of detection and mitigation measures. Therefore, this review aims to shed light on sources of CIT, its prevalence in food and feed, biosynthetic pathways, and genes involved, with a major focus on detection and management strategies to ensure the safety and security of food and feed.

Citrinin in Foods and Supplements: A Review of Occurrence and Analytical Methodologies

Citrinin (CIT) deserves attention due to its known toxic effects in mammalian species and its widespread occurrence in food commodities, often along with ochratoxin A, another nephrotoxic mycotoxin. Human exposure, a key element in assessing risk related to food contaminants, depends upon mycotoxin contamination levels in food and on food consumption. Commercial supplements, commonly designated as red rice, usually used in daily diets in Asiatic countries due to their medicinal properties, may pose a health problem as a result of high CIT levels. In addition to the worldwide occurrence of CIT in foods and supplements, a wide range of several analytical and detection techniques with high sensitivity, used for evaluation of CIT, are reviewed and discussed in this manuscript. This review addresses the scientific literature regarding the presence of CIT in foods of either vegetable or animal origin, as well as in supplements. On what concerns analytical methodologies, sample extraction methods, such as shaking extraction and ultrasonic assisted extraction (UAE), clean-up methods, such as liquid-liquid extraction (LLE), solid phase extraction (SPE) and Quick, Easy, Cheap, Effective, Rugged and Safe (QuECHERS), and detection and quantification methods, such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE), biosensors, and ELISA, are also reviewed.

Study of photodegradation kinetics of aflatoxins in cereals using trilinear component modeling of excitation-emission matrix fluorescence data

In this work, a smart analytical strategy that combines excitation-emission matrix (EEM) fluorescence detection with alternating trilinear decomposition (ATLD) algorithm was developed for fast, on-line and interference-free study on the photodegradation kinetics of aflatoxin B₁ (AFB₁) and aflatoxin G₁ (AFG₁) in rice and wheat under UV-Vis light (λ = 250-500 nm) treatment. With the aid of prominent "second-order advantage" of ATLD method, pure fluorescence signals of two targeted analytes can be directly resolved out from heavily overlapping spectral environment and accurately quantified even in the presence of unknown matrix interferences. Cereal samples in kinetic processing of photodegradation were detected without complex pretreatment steps except for a simple extraction using methanol/water solution (4:1, v/v), which solves the problem facing varied matrix interferences in the case of on-line monitoring of aflatoxins. The kinetic signals of analytes of interest were directly extracted regardless of varied matrix backgrounds of various cereals. The kinetic curves and degradation speeds of AFB₁ and AFG₁ can be estimated by resolved quantitative data, optimal radiation conditions including 365 nm wavelength and 35 J m^-2 density were discussed for high-efficiency detoxification control of aflatoxins in rice and wheat. This strategy was promising to be as an alternative tool for eco-friendly photodegradation kinetic study of mycotoxins or other hazards in complex foodstuff matrixes.

Occurrence of Fusarium mycotoxins and toxigenic Fusarium species in freshly harvested rice in Jiangsu, China

In 2017, 236 rice samples were collected from 42 counties in Jiangsu province, China, and analysed for Fusarium mycotoxins. Mycotoxin analyses showed that deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), nivalenol (NIV), fusarenone X (FUS-X), zearalenone (ZEA), fumonisins (including FB1, FB2, and FB3), and beauvericin (BEA) were present in unhusked rice samples. Regional differences in mycotoxin contamination of unhusked rice were attributed to differences in precipitation during rice anthesis and agricultural practices among the three study regions. Importantly, the mean concentrations of DON, NIV, ZEA, and fumonisins in white rice were significantly lower than those in unhusked rice, and the relative proportion of the toxins in rice by-products exceeded 84%. Fusarium isolates were then obtained from the unhusked rice samples; Fusarium asiaticum was the most common, followed by Fusarium fujikuroi, Fusarium proliferatum, Fusarium verticillioides, and Fusarium commune. Genotype and chemical analyses of mycotoxins showed that most F. asiaticum isolates (71%) were 3-ADON chemotypes; the remainder were NIV producers. All of the F. proliferatum and F. verticillioides isolates, and most of the F. fujikuroi isolates produce fumonisins, and most of the three species coproduced BEA. The present study is the first to evaluate Fusarium mycotoxins and toxigenic Fusarium species from rice freshly harvested in Jiangsu province, China. The results of this study improve our understanding the population dynamics of Fusarium species in rice and the development of effective control measures.

Occurrence of mycotoxins in rice consumed by Iranians: a probabilistic assessment of risk to health

Risks based on cancer and non-cancer endpoints, to Iranians from exposure to several mycotoxins (aflatoxin B1, ochratoxin, deoxynivalenol and T-2 toxin) following consumption of rice were evaluated. Point estimates of hazard were made for each mycotoxin and a hazard index (HI) and probabilistic estimates were based on results of Monte Carlo Simulations (MCS). All known 17 peer-reviewed studies, published in databases included in Science Direct, PubMed, Scopus and Web of Science, as well as grey literature published in Google Scholar from 2008 to 2017 were considered. The 95^th and 50^th centiles of Hazard Index (HI) in Iranians due to ingestion of rice were estimated to be 2.5 and 0.5, respectively. The 95^th and 50^th centiles of people with positive surface antigens for hepatitis B (HBsAg+) risk characterisation for AFB₁ in Iranian consumers of rice were 81 and 79.1, respectively. The 95^th and 50^th centiles for risks of Iranians negative for the surface antigen of hepatitis B HBsAg (HBsAg-) were 4.4 and 2.6, respectively. Based on results of the MCS for risks to cancer effects, the 95^th and 50^th centiles of margins of exposure (MOE) were 233 and 231, respectively. Therefore, it is recommended to update agricultural approaches and storage methods and implement monitoring and regulations based on risks to health posed by consumption of rice by the Iranian population.

Inhibition of aflatoxin B1 biosynthesis and down regulation of aflR and aflB genes in presence of benzimidazole derivatives without impairing the growth of Aspergillus flavus

Aflatoxins are mutagenic secondary metabolites produced by certain ubiquitous saprophytic fungi. These contaminate agricultural crops and pose a serious health threat to humans and livestock all over the world. Benzimidazole and its derivatives are biologically active heterocyclic compounds known for their fungicidal activity. In the present study, second and sixth position substituted benzimidazole derivatives are tested for their antifungal and anti-aflatoxigenic activity. Aflatoxigenic strain of Aspergillus flavus cultured in Yeast extract sucrose (YES) medium as well as in rice in the presence and absence of test compounds. 2-(2-Furyl) benzimidazole (FBD) showed complete inhibition of fungal growth at 50 μg/mL. However, the polar derivatives of FBD viz. 6-NFBD, 6-AFBD, 6-CAFBD, and 6-CFBD did not impair the fungal growth but effectively inhibited aflatoxin B₁ biosynthesis. Significant down-regulation of aflR gene involved in regulation and aflB structural gene for aflatoxin B₁ biosynthesis was observed in presence of 6-NFBD. These benzimidazole derivatives also showed good anti-aflatoxigenic activity in rice, though the IC₅₀ concentrations in rice were comparatively higher than those in YES medium. This study summarizes the most notable structure-activity relationship (SAR) of 2-(2-Furyl) benzimidazoles for anti-aflatoxigenic and anti-fungal activities. These molecules can be further studied for their applications in industrial fermentation processes vulnerable to mold growth and subsequent aflatoxin B₁ synthesis like koji fermentation, cheese production, etc.

Interaction of water activity and temperature on the growth, gene expression and aflatoxin production by Aspergillus flavus on paddy and polished rice

Water activity (a_w) and temperature are two pivotal environmental factors affecting Aspergillus flavus growth and aflatoxin production. Here, we found that AFB₁ production on polished rice can occur over a wider range of temperature × a_w levels than that on paddies. For fungal growth on polished rice, the optimum conditions were a_w 0.92-0.96 and 28-37 °C. The maximum amounts of AFB₁ on polished rice was observed at 33 °C and a_w 0.96. Compared to 33 °C, all tested genes of A. flavus on polished rice were significantly up-regulated at 25 °C under a_w 0.96. The late structural genes of pathway were significantly down-regulated at 37 °C under a_w 0.96, although aflR and aflS and most of early structural genes were up-regulated. Compared to a_w 0.96, most of pathway genes were significantly down-regulated at a_w 0.90 and 0.99 under 33 °C, although two regulatory genes were up-regulated at a_w 0.90.

Pre- and Postharvest Strategies to Minimize Mycotoxin Contamination in the Rice Food Chain

Rice is part of many people's diet around the world, being the main energy source in some regions. Although fewer reports exist on the occurrence of mycotoxins in rice compared to other cereals, fungal contamination and the associated production of toxic metabolites, even at lower occurrence levels compared to other crops, are of concern because of the high consumption of rice in many countries. Due to the diversity of fungi that may contaminate the rice food chain, the co-occurrence of mycotoxins is frequent. Specific strategies to overcome these problems may be applied at the preharvest part of the crop chain, while assuring good practices at harvest and postharvest stages, since different fungi may find suitable conditions to grow at the various stages of the production chain. Therefore, the aim of this review is to present the state-of-the-art knowledge on such strategies in an integrated way, from the field to the final products, to reduce mycotoxin contamination in rice.

The Caryopsis of Red-Grained Rice Has Enhanced Resistance to Fungal Attack

Seed persistence in the soil is threatened by microorganisms, but the seed coat helps protect the seed from them. Although modern rice (Oryza sativa L.) cultivars have a whitish caryopsis, some varieties have a red caryopsis coat, a trait typical of wild Oryza species. The red colour is due to the oxidation of proanthocyanidins, a class of flavonoids that is found in the outer layers of the seed in many species. We aimed to assess whether these natural compounds (proanthocyanidins and proanthocyanidin-derived pigment) have some protective effect against microbial attacks. Dehulled caryopses of white-grained and red-grained rice genotypes were employed to assay fungal infection. Specifically, three white-grained rice cultivars (Perla, Augusto, and Koral) and three red-grained rice varieties (Perla Rosso, Augusto Rosso, and Koral Rosso) were used. In a first test, the caryopses were infected with Epicoccum nigrum at 10 °C, and seedling growth was then assessed at 30 °C. In a second test, the degree of infection by the mycotoxigenic fungus Fusarium sporotrichioides was assayed by measuring the accumulation of T-2/HT-2 toxins in the caryopses. Infection was performed at 10 °C to prevent rice germination while allowing fungal growth. In both the tests, red caryopses showed reduced, or delayed, infection with respect to white ones. One black-grained cultivar (Venere) was assayed for the accumulation of T-2/HT-2 toxins as well, with results corresponding to those of the red-grained rice varieties. We argue that the red pigment accumulating in the caryopsis coat, and/or the proanthocyanidins associated with it, provides a protective barrier against challenging microorganisms.

Association between Urinary Aflatoxin (AFM₁) and Dietary Intake among Adults in Hulu Langat District, Selangor, Malaysia

Aflatoxin is a food contaminant and its exposure through the diet is frequent and ubiquitous. A long-term dietary aflatoxin exposure has been linked to the development of liver cancer in populations with high prevalence of aflatoxin contamination in foods. Therefore, this study was conducted to identify the association between urinary aflatoxin M₁ (AFM₁), a biomarker of aflatoxin exposure, with the dietary intake among adults in Hulu Langat district, Selangor, Malaysia. Certain food products have higher potential for aflatoxin contamination and these were listed in a Food Frequency Questionnaire, which was given to all study participants. This allowed us to record consumption rates for each food product listed. Concomitantly, urine samples were collected, from adults in selected areas in Hulu Langat district, for the measurement of AFM₁ levels using an ELISA kit. Of the 444 urine samples collected and tested, 199 were positive for AFM₁, with 37 of them exceeding the limit of detection (LOD) of 0.64 ng/mL. Cereal products showed the highest consumption level among all food groups, with an average intake of 512.54 g per day. Chi-square analysis showed that consumption of eggs (X² = 4.77, p = 0.03) and dairy products (X² = 19.36, p < 0.01) had significant associations with urinary AFM₁ but both food groups were having a phi and Cramer’s V value that less than 0.3, which indicated that the association between these food groups’ consumption and AFM₁ level in urine was weak.

Co-occurrence of citrinin and ochratoxin A in rice in Asia and its implications for human health

Citrinin (CIT) and ochratoxin A (OTA) are nephrotoxic mycotoxins, produced by several Aspergillus and Penicillium species and their co-occurrence in rice may cause health effects in humans. Rice is an important food crop worldwide and is a major staple food in Asia which may be invaded by CIT and OTA producing fungal spores in the field, during harvest and storage. Humans are exposed to these mycotoxins through ingestion of contaminated rice and other food commodities. Yet, data on the combined presence to these food contaminants are still insufficient to estimate human exposure in Asia. This review describes the prevalence of CIT and OTA in rice in Asia and its implications on human health, which may help in establishing and carrying out proper management strategies against mould development on rice. From the health point of view, combined exposition of CIT and OTA should be a public concern as both are nephrotoxic and long-term exposure can pose detrimental health effects. Thus, it is necessary for local farmers and food factories to implement strict measures and to improve methods for rice preservation during the distribution to consumers, particularly in the markets. Moreover, regular surveys for CIT and OTA occurrence in rice and human biomonitoring are recommended to reduce the health effects in Asian population. © 2017 Society of Chemical Industry.

Multiple Mycotoxins in Rice: Occurrence and Health Risk Assessment in Children and Adults of Punjab, Pakistan

Mycotoxin contamination in rice can create a health risk for the consumers. In this study, the measurement of 23 mycotoxins in rice samples (n = 180) was performed using a validated LC–MS/MS method. A food frequency questionnaire was used to get rice consumption data for the assessment of mycotoxin dietary exposure, before calculating the health risk in adults and children of north and south regions of the Pakistani Punjab province. The prevalence of aflatoxin B₁ (56%), aflatoxin B₂ (48%), nivalenol (28%), diacetoxyscirpenol (23%), fumonisin B₁ (42%), zearalenone (15%), HT-2 toxin (10%), deoxynivalenol (8%), and ochratoxin A (6%) was estimated in samples with a mean concentration range between 0.61 and 22.98 µg/kg. Aflatoxin degradation by traditional Pakistani cooking recipes was evaluated and observed to be 41–63%. The dietary exposure to aflatoxins exceeded the tolerable daily intake at all levels, and ochratoxin A and zearalenone posed health risk at high contamination and high consumption levels. The margin of aflatoxin B₁ exposure ranged between 10 and 69 in adults and 10 and 62 in children. The mean cancer risk by aflatoxin B₁ exposure was 0.070 (adults) and 0.071 (children) cases/year/100,000 people in South Punjab population, and 0.122 (adults) and 0.127 (children) cases/year/100,000 people in North Punjab population. This study will provide new insights for the planning and management of mycotoxins in Pakistan.

Simple determination of aflatoxins in rice by ultra-high performance liquid chromatography coupled to chemical post-column derivatization and fluorescence detection

A fast and simple analytical method was developed and characterized for the determination of aflatoxins (B₁, B₂, G₁ and G₂) in rice. The procedure is based on a simple solid-liquid extraction without further clean-up, and analysis by ultra-high performance liquid chromatography coupled with fluorescence detection. Fluorescence emission of aflatoxins B₁ and G₁ was enhanced by post-column chemical derivatization using pyridinium bromide perbromide. The analytical method was satisfactorily characterized in white and brown rice. Under optimum conditions, external calibration in solvent could be used for quantification purposes and limits of quantification were below the maximum contents established by the European Union regulation for these contaminants/commodity group combination (0.07-0.14 µg/kg for white rice and 0.20-0.28 µg/kg for brown rice). Recovery studies carried out at three different concentration levels (0.5, 2 and 5 µg/kg) showed values in the range of 84.5-105.3%, and RSDs ≤ 5%.

Sterigmatocystin Occurrence in Paddy and Processed Rice Produced in Italy in the Years 2014-2015 and Distribution in Milled Rice Fractions

The occurrence of sterigmatocystin (STC) in paddy and processed rice samples produced in Italy was surveyed. After extraction and purification, STC was analysed using HPLC-MS/MS. STC was detected in all paddy rice samples (n = 49), in the range 0.29–15.85 μg·kg⁻¹. As regards processed rice, a widespread contamination was found in brown and parboiled rice. All the brown rice samples were contaminated between 0.12 and 1.32 μg·kg⁻¹; for parboiled rice, the incidence was 90.9% and the maximum level was 1.09 μg·kg⁻¹. The contamination in white rice was significantly lower (p < 0.01). The STC distribution in different rice fractions, obtained by the de-hulling and polishing processes, was evaluated. After de-hulling, the STC percentage remaining in brown rice was in the range 21.2%–30.8%. The polishing process, from brown to white rice, caused another remarkable decrease of contamination; the STC remaining in white rice was 2.2%–8.3% of the amount found in paddy rice.

The Potential of Streptomyces as Biocontrol Agents against the Rice Blast Fungus, Magnaporthe oryzae (Pyricularia oryzae)

Rice is a staple food source for more than three billion people worldwide. However, rice is vulnerable to diseases, the most destructive among them being rice blast, which is caused by the fungus Magnaporthe oryzae (anamorph Pyricularia oryzae). This fungus attacks rice plants at all stages of development, causing annual losses of approximately 10-30% in various rice producing regions. Synthetic fungicides are often able to effectively control plant diseases, but some fungicides result in serious environmental and health problems. Therefore, there is growing interest in discovering and developing new, improved fungicides based on natural products as well as introducing alternative measures such as biocontrol agents to manage plant diseases. Streptomyces bacteria appear to be promising biocontrol agents against a wide range of phytopathogenic fungi, which is not surprising given their ability to produce various bioactive compounds. This review provides insight into the biocontrol potential of Streptomyces against the rice blast fungus, M. oryzae. The ability of various Streptomyces spp. to act as biocontrol agents of rice blast disease has been studied by researchers under both laboratory and greenhouse/growth chamber conditions. Laboratory studies have shown that Streptomyces exhibit inhibitory activity against M. oryzae. In greenhouse studies, infected rice seedlings treated with Streptomyces resulted in up to 88.3% disease reduction of rice blast. Studies clearly show that Streptomyces spp. have the potential to be used as highly effective biocontrol agents against rice blast disease; however, the efficacy of any biocontrol agent may be affected by several factors including environmental conditions and methods of application. In order to fully exploit their potential, further studies on the isolation, formulation and application methods of Streptomyces along with field experiments are required to establish them as effective biocontrol agents.