Occurrence of Ochratoxin A in Coffee: Threads and Solutions—A Mini-Review

Influence of temperature, relative humidity, and storage time conditions on ochratoxin a production by Aspergillus niger fungi in dry parchment coffee

The influence of temperature, relative humidity, and storage time on the production of Ochratoxin A by the fungus Aspergillus niger in dry parchment coffee was determined under controlled laboratory conditions. Additionally, the roasting curve that would achieve maximum reduction of OTA concentration in roasted coffee was evaluated. The objective was to establish strategies to reduce the risk of product contamination by this mycotoxin in coffee farms and its presence in coffee ready for consumption. For the analysis of the influence of temperature, relative humidity, and storage times on OTA production, sterilized coffee samples incubated with the A. niger strain were used. To obtain the roasting curves, coffee samples stored for 15 days at a temperature of 23 °C and relative humidity of 60% were employed. The OTA concentration of each study samples was quantified by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). The results obtained enabled: (1) The understanding of the conditions of temperature, relative humidity, and storage time that favor the production of the toxin by A. niger, thus allowing the development of coffee storage protocols that reduce grain contamination by this toxin, as it was found that increases in storage time and decreases in temperature and relative humidity to certain values are associated with increases in OTA concentration in the DPC. (2) Identifying the roasting curve whereby the coffee was subjected to temperatures from 180 °C to 208.8 °C for 11.23 min, achieving an OTA degradation of 76.4%. This curve serves as a guide for the adjustment of the temperatures and roasting times around the variables present in the process, achieving different roasting profiles, a significant reduction of OTA without affecting the quality of the coffee, and facilitating different chemical, physical, and organoleptic characteristics that can accommodate consumers' tastes and ensure a safe beverage.

Efficacy of fungal antagonists against aflatoxins, ochratoxin A, and fumonisins at different pathogen:antagonist inoculum ratios on grain corn agar and grain corn kernel

AIM

The present work investigated the efficacy of native biocontrol candidates (antagonists) against aflatoxins, ochratoxin A (OTA), and fumonisins produced by native mycotoxigenic fungi isolated from Malaysia at different pathogen: antagonist inoculum ratios on grain corn agar and grain corn kernels.

METHODS AND RESULTS

Five pathogen: antagonist inoculum ratios (100:0, 75:25, 50:50, 25:75, and 0:100) were employed. Non-aflatoxigenic Aspergillus flavus Af1KD and Af5TD, and Penicillium janthinellum were used against aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) by A. flavus. Against OTA by A. niger, and fumonisin B1 (FB1) and fumonisin B2 (FB2) by Fusarium verticillioides and F. proliferatum, respectively, the antagonists Trichoderma asperelloides, T. asperellum, and T. harzianum were used. Non-aflatoxigenic A. flavus Af1KD was the most effective against AFB1 and AFB2 at all tested ratios and substrates. All Trichoderma spp. were effective against OTA by A. niger on grain corn agar at all tested ratios. Trichoderma asperelloides and T. asperellum were effective against FB1 and FB2 produced by F. verticillioides at all tested ratios and substrates. Trichoderma asperelloides was effective against FB1 and FB2 by F. proliferatum at all tested ratios and substrates.

CONCLUSION

The native biocontrol candidates were effective against mycotoxigenic fungi and mycotoxin production on grain corn agar and grain corn kernels, and could be developed into biocontrol agents.

Evaluation of the application of wild yeasts in inhibiting germination of ochratoxin-producing Fungi during coffee fermentation process

Specialty coffee, typically lightly roasted, is valued for its unique fruity aroma. However, the fermentation process poses a risk of contamination with ochratoxin-producing fungi. This study aimed to select wild yeast strains capable of contributing distinctive flavor profiles while inhibiting the growth of ochratoxin-producing fungi. Coffee pulp served as a substrate to simulate yeast growth during coffee fermentation, allowing for the evaluation of yeast metabolites potential to inhibit spore germination in ochratoxin-producing fungi (Aspergillus niger). The findings demonstrated that the Saccharomyces cerevisiae strain effectively inhibited spore germination in A. niger. High-performance liquid chromatography (HPLC) analysis indicated that citric acid is likely the primary organic acid responsible for inhibiting A. niger spore germination. These results suggested that S. cerevisiae has potential applications in enhancing the food safety of coffee.

Occurrence of ochratoxins in coffee and risk assessment of ochratoxin a in a Costa Rican urban population

Costa Rica is a coffee producer and consumer country, but this product is prone to ochratoxin contamination; therefore, this study aims evaluates the human health risk associated with ochratoxin exposure among coffee consumers in the Costa Rica. Ochratoxin A (OTA) is a nephrotoxic compound classified as a Group 2B carcinogen, produced by the fungi Aspergillus section Circumdati, Aspergillus section Nigri and Penicillium spp.  The presence of OTA and ochratoxin B (OTB) in Costa Rican coffee products (n = 175) was determined by HPLC with fluorescence detection. OTA was detected in 58.2% of the green coffee beans (1.01 ± 0.85 ng g -1), in 36.8% of the pure roasted coffee (2.59 ± 4.41 ng g -1), in 23.1% of the sugar-added roasted coffee (1.59 ± 0.33 ng g-1) and 75% of the instant coffee samples (0.69 ± 0.58 ng g-1). The contamination with OTB was 45.5% (1.28 ± 0.83 ng g -1), 31.6% (1.60 ± 2.04 ng g -1), 30.8% (1.42 ± 0.86 ng g -1), and 41.7% (2.64 ± 2.07 ng g -1), respectively. The dietary exposure to OTA of the Costa Rican population was assessed by a probabilistic approach. The mean estimated daily intake (EDI) of OTA from coffee was: 0.184 (90% IC: 0.179-0.189) ng kg-1 bw day-1 for the total population (0.189 [90% IC: 0.184-0.194] ng kg-1 bw day-1 for males and 0.181 [90% IC: 0.176-0.186] ng kg-1 bw day-1 for females).  The EDIs were lower than the tolerable human intake benchmarks for OTA set by international food safety authorities (even though more than 80% of OTA is extracted during coffee preparation). The results evidence a low risk (related to ochratoxin) for coffee consumers in Costa Rica.

A worldwide systematic review of ochratoxin A in various coffee products - human exposure and health risk assessment

Coffee is one of the most commonly consumed beverages worldwide, so assessing its quality for potential health risks is essential. Therefore, this review aimed to determine the levels of ochratoxin A (OTA) in coffee worldwide and then estimate its human intake and health risks. The systematic search took place from June 1997 to April 2024 and 40 of 254 articles were selected based on the selection criteria. The results showed significant differences in average levels of OTA between countries, continents and coffee types (p < 0.001). Of 3256 samples, OTA was detected in 1778, accounting for 54.6% of the total, with the percentage of positive results varying between 7.5% and 100%. Only two studies reported OTA average levels in roasted coffee exceeding the maximum limit (ML) set by the European Commission (ML-EC = 5 μg/kg). The average OTA in soluble coffee was lower than ML-EC (10 μg/kg) in all studies, and in instant coffee, the level of OTA was higher than ML-EC (10 μg/kg) only in one study. The estimated daily intake (EDI) of OTA in all coffee types was lower than the provisional tolerable daily intake (PTDI) values set by joint FAO/WHO Expert Committee on Food Additives (JECFA) (14 ng/kg bw/day) and proposed by the European Food Safety Authority (EFSA) (17 ng/kg bw/day). Non-carcinogenic risk assessment through coffee consumption indicated that the hazard quotient (HQ) was below the acceptable level, HQ = 1. The Margin of Exposure (MoE) for neoplastic effects was acceptable and unacceptable for non-neoplastic effects (NNE) in 4.5% (one of 22 cases) of the roasted and soluble coffees, but acceptable for all instant coffees. In conclusion, the study shows that the OTA content of coffee is not toxic to consumers worldwide. However, preventative measures should be taken, including inhibiting fungal growth and reducing OTA-producing fungal growth.

Reduction in Ochratoxin A Occurrence in Coffee: From Good Practices to Biocontrol Agents

Ochratoxin A (OTA) is a mycotoxin mainly produced by Aspergillus section Circumdati and section Nigri across the coffee chain. OTA is nephrotoxic and is a threat to human health. This review summarizes current knowledge on how to reduce OTA concentration in coffee from farm to cup. After a brief introduction to the OTA occurrence in coffee, current good management practices are introduced. The core of this review focuses on biocontrol and microbial decontamination by lactic acid bacteria, yeasts and fungi, and their associated enzymes currently reported in the literature. Special attention is given to publications closest to in vivo applications of biocontrol agents and microbial OTA adsorption or degradation agents. Finally, this review provides an opinion on which future techniques to promote within the coffee supply chain.

Ochratoxin A in coffee and coffee-based products: a global systematic review, meta-analysis, and probabilistic risk assessment

Contamination of food with mycotoxins can pose harmful effects on the health of consumers in the long term. Coffee contamination with mycotoxins has become a global concern. This study attempted to meta-analyze the concentration and prevalence of ochratoxin A (OTA) in coffee products and estimate consumers' health risks. The search was conducted among international databases, including Scopus, PubMed, Embase, and Web of Science, for 1 January 2010 to 1 May 2022. The concentration and prevalence of OTA in coffee products were meta-analyzed according to country subgroups. Health risk assessment was conducted based on Margin of Exposures (MOEs) using the Monte Carlo simulation (MCS) technique. The three countries that had the highest Pooled concentration of OTA in coffee were observed in Chile (100.00%), Kuwait (100.00%), and France (100.00%). The overall prevalence of OTA in coffee products was 58.01%, 95% CI (48.37-67.39). The three countries that had the highest concentration of OTA were Philippines (39.55 μg/kg) > Turkey (39.32 μg/kg) > and Panama (21.33 μg/kg). The mean of MOEs in the adult consumers in Panama (9,526) and the Philippines (8,873) was lower than 10,000, while the mean of MOEs in other countries was higher than 10,000. Therefore, monitoring and control plans should be carried out in different countries.

The Toxicokinetics, Excretion Patterns, and Milk Transmission of Ochratoxin A in Lactating Sows

Ochratoxin A (OTA), a mycotoxin commonly found in feedstuffs, is known for its detrimental effects on the kidneys and liver, posing significant health risks to animals and humans. This study investigated the toxicokinetics, excretion patterns, and milk transmission of Ochratoxin A (OTA) in lactating sows. The sows were administered a single oral dose of 500 μg/kg BW (body weight), followed by the systematic sampling of plasma, feces, urine, and milk. Plasma samples were collected at 0, 5, 15, and 30 min, and 1, 2, 3, 6, 9, 12, 24, 48, 72, 88, 96, and 120 h post administration. Feces samples were collected at 6 h intervals for the first 12 h, then at 12 h intervals until 120 h, while urine samples were collected at 6 h intervals up to 120 h. Milk samples were collected at 0, 6, 12, 24, 36, 48, 72, 96, and 120 h. The concentration of OTA and its primary metabolite OTα were quantitatively analyzed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The results revealed that the peak plasma concentrations of OTA (920.25 ± 88.46 μg/L) were observed at 9 h following administration. The terminal elimination half-life was recorded at 78.47 ± 7.68 h, with a volume of distribution of 0.16 ± 0.003 L/kg. Moreover, this study documented the excretion of OTA and OTα across a span of 120 h, revealing that feces and urine accounted for 18.70 ± 0.04% and 8.40 ± 0.002% of the total intake amounts, respectively (calculated based on substance amounts). Furthermore, this experiment detected OTA residues in the milk of lactating sows, with the milk-to-plasma (M/P) ratio initially increasing from 0.06 to 0.46 within the first 24 h following OTA ingestion. These findings offer an exhaustive temporal analysis of OTA's toxicokinetics in lactating sows, emphasizing its pervasive distribution and elimination through various bodily excreta.

Ochratoxin A detoxification potentials of basil, chan, and chia seeds

The most toxic of the ochratoxins is ochratoxin A (OTA), which is primarily produced by species of Aspergillus and Penicillium that can be found in maize, wheat, coffee, red wine, and various grains. OTA induces immunotoxicity, nephrotoxicity, hepatotoxicity, teratogenicity, and carcinogenicity in both animals and humans. Thus, there is a need to identify mycotoxin detoxification agents that can effectively decontaminate OTA. Seeds of basil (Ocimum basilicum L.), chan (Hyptis suaveolens L.), and chia (Salvia hispanica L.) are functional foods capable of eliminating harmful substances. Despite this potential, the impact of these seeds on OTA detoxification remains unclear. This study reveals that milled basil, chan, and chia seeds adsorb significant levels of OTA, with chia demonstrating the highest adsorption capacity, followed by chan and basil seeds showing the least efficiency. Furthermore, milled basil, chan, and chia seeds effectively reduced OTA residues in artificial gastric and intestinal fluids, where they achieved up to 93% OTA adsorption in the former. In addition, these milled seeds were able to remove OTAs from canned, drip, and instant coffee. This study is the first to report the OTA elimination potential of basil, chan, and chia seeds.

Bacillus licheniformis M2-7 Decreases Ochratoxin A Concentrations in Coffee Beans During Storage

Microbial contamination of coffee beans arises from various factors such as harvesting, handling, and storage practices, during which ochratoxin A (OTA)-producing fungi develop and proliferate. The presence of elevated concentrations of OTA poses a serious health risk to coffee consumers. Therefore, the implementation of a post-harvest treatment involving the use of bacteria known to antagonize OTA-producing fungi constitutes a safe alternative for reducing or eliminating the toxin's concentration in coffee beans. In this study, coffee beans (Coffea arabica L.) were inoculated with Bacillus licheniformis M2-7, after which we monitored fungal growth, in vitro antagonism, and OTA concentration. Our findings demonstrated that coffee beans inoculated with this bacterial strain exhibited a significant decrease in fungal populations belonging to the genera Aspergillus and Penicillium, which are known to produce OTA. Moreover, strain M2-7 decreased the growth rates of these fungi from 67.8% to 95.5% (P < 0.05). Similarly, inoculation with B. licheniformis strain M2-7 effectively reduced the OTA concentration from 24.35 ± 1.61 to 5.52 ± 1.69 µg/kg (P < 0.05) in stored coffee beans. These findings suggest that B. licheniformis M2-7 holds promise as a potential post-harvest treatment for coffee beans in storage, as it effectively inhibits the proliferation of OTA-producing fungi and lowers the toxin's concentration.

Ochratoxin A: Overview of Prevention, Removal, and Detoxification Methods

Ochratoxins are the secondary metabolites of Penicillium and Aspergillus, among which ochratoxin A (OTA) is the most toxic molecule. OTA is widely found in food and agricultural products. Due to its severe nephrotoxicity, immunotoxicity, neurotoxicity, and teratogenic mutagenesis, it is essential to develop effective, economical, and environmentally friendly methods for OTA decontamination and detoxification. This review mainly summarizes the application of technology in OTA prevention, removal, and detoxification from physical, chemical, and biological aspects, depending on the properties of OTA, and describes the advantages and disadvantages of each method from an objective perspective. Overall, biological methods have the greatest potential to degrade OTA. This review provides some ideas for searching for new strains and degrading enzymes.

Climate Change-A Global Threat Resulting in Increasing Mycotoxin Occurrence

During the last decade, scientists have given increasingly frequent warnings about global warming, linking it to mycotoxin-producing moulds in various geographical regions across the world. In the future, more pronounced climate change could alter host resilience and host-pathogen interaction and have a significant impact on the development of toxicogenic moulds and the production of their secondary metabolites, known as mycotoxins. The current climate attracts attention and calls for novel diagnostic tools and notions about the biological features of agricultural cultivars and toxicogenic moulds. Since European climate environments offer steadily rising opportunities for Aspergillus flavus growth, an increased risk of cereal contamination with highly toxic aflatoxins shall be witnessed in the future. On top of that, the profile (representation) of certain mycotoxigenic Fusarium species is changing ever more substantially, while the rise in frequency of Fusarium graminearum contamination, as a species which is able to produce several toxic mycotoxins, seen in northern and central Europe, is becoming a major concern. In the following paper, a high-quality approach to a preventative strategy is tailored to put a stop to the toxicogenic mould- and mycotoxin-induced contamination of foods and feeds in the foreseeable future.

Antifungal effects of selected menthol and eugenol in vapors on green coffee beans during long-term storage

Nowadays, coffee (Coffea Arabica L.) is among the most significant agricultural products of the world and drinking coffee has become one of the most popular habits in the world. The main contamination of stored coffee beans is related with the mycotoxin produced by the toxigenic fungi belonging the genus Aspergillus. Fungal infection followed by mycotoxin biosynthesis in coffee results in notable financial losses. subsequent mycotoxin biosynthesis in coffee leads to major economic losses. Complications ranging from mild to severe can be caused by the mycotoxins produced by this genus. The aim of this investigation was to determine the effect of menthol and eugenol on Aspergillus parasiticus (CBS 100926^T) growth, spore germination, and their potential use as green coffee beans preservative during long-term storage (12 months). The minimum inhibitory concentrations (MICs) values of the menthol and eugenol were recorded to completely inhibit the growth of A. parasiticus in 400 μg/ml and 300 μg/ml, respectively. Both reduced spore germination by 9.33% and 5.66% at 300 μg/ml and 200 μg/ml, respectively. They showed efficacy in fumigated green coffee beans sample during the storage for up to 12 months providing an increase in the protection level of 62.5% for menthol and 73.21% for eugenol against the A. parasiticus contamination. This suggests that menthol and eugenol could be used as good alternatives for decreasing the deteriorations due to the fungal infections in green coffee beans during long-term storage.

Pumpkin extract and fermented whey individually and in combination alleviated AFB1- and OTA-induced alterations on neuronal differentiation invitro

Food and feed are daily exposed to mycotoxin contamination which effects may be counteracted by functional compounds like carotenoids and fermented whey. Among mycotoxins, the most toxic and studied are aflatoxin B1 (AFB1) and ochratoxin A (OTA), which neurotoxicity is not well reported. Therefore, SH-SY5Y human neuroblastoma cells ongoing differentiation were exposed during 7 days to digested bread extracts contained pumpkin and fermented whey, individually and in combination, along with AFB1 and OTA and their combination, in order to evaluate their presumed effects on neuronal differentiation. The immunofluorescence analysis of βIII-tubulin and dopamine markers pointed to OTA as the most damaging treatment for cell differentiation. Cell cycle analysis reported the highest significant differences for OTA-contained bread compared to the control in phase G₀/G₁. Lastly, RNA extraction was performed and gene expression was analyzed by qPCR. The selected genes were related to neuronal differentiation and cell cycle. The addition of functional ingredients in breads not only enhancing the expression of neuronal markers, but also induced an overall improvement of gene expression compromised by mycotoxins activity. These data confirm that in vitro neuronal differentiation may be impaired by AFB1 and OTA-exposure, which could be modulated by bioactive compounds naturally found in diet.

Comprehensive Review of Fungi on Coffee

Coffee is grown in more than 80 countries as a cash crop and consumed worldwide as a beverage and food additive. It is susceptible to fungal infection during growth, processing and storage. Fungal infections, in particular, can seriously affect the quality of coffee and threaten human health. The data for this comprehensive review were collected from the United States Department of Agriculture, Agricultural Research Service (USDA ARS) website and published papers. This review lists the fungal species reported on coffee based on taxonomy, life mode, host, affected plant part and region. Five major fungal diseases and mycotoxin-producing species (post-harvest diseases of coffee) are also discussed. Furthermore, we address why coffee yield and quality are affected by fungi and propose methods to control fungal infections to increase coffee yield and improve quality. Endophytic fungi and their potential as biological control agents of coffee disease are also discussed.

Ochratoxin A in Slaughtered Pigs and Pork Products

Ochratoxin A (OTA) is a mycotoxin that is produced after the growth of several Aspergillus and Penicillium spp. in feeds or foods. OTA has been proved to possess nephrotoxic, hepatotoxic, teratogenic, neurotoxic, genotoxic, carcinogenic and immunotoxic effects in animals and humans. OTA has been classified as possibly carcinogenic to humans (Group 2B) by the IARC in 2016. OTA can be mainly found in animals as a result of indirect transmission from naturally contaminated feed. OTA found in feed can also contaminate pigs and produced pork products. Additionally, the presence of OTA in pork meat products could be derived from the direct growth of OTA-producing fungi or the addition of contaminated materials such as contaminated spices. Studies accomplished in various countries have revealed that pork meat and pork meat products are important sources of chronic dietary exposure to OTA in humans. Various levels of OTA have been found in pork meat from slaughtered pigs in many countries, while OTA levels were particularly high in the blood serum and kidneys of pigs. Pork products made from pig blood or organs such as the kidney or liver have been often found to becontaminated with OTA. The European Union (EU) has established maximum levels (ML) for OTA in a variety of foods since 2006, but not for meat or pork products. However, the establishement of an ML for OTA in pork meat and meat by-products is necessary to protect human health.

In vitro and in vivo evaluation of AFB1 and OTA-toxicity through immunofluorescence and flow cytometry techniques: A systematic review

Due to the globalization, mycotoxins have been considered a major risk to human health being the main contaminants of foodstuffs. Among them, AFB1 and OTA are the most toxic and studied. Therefore, the goal of this review is to deepen the knowledge about the toxicological effects that AFB1 and OTA can induce on human health by using flow cytometry and immunofluorescence techniques in vitro and in vivo models. The examination of the selected reports shows that the majority of them are focused on immunotoxicity while the rest are concerned about nephrotoxicity, hepatotoxicity, gastrointestinal toxicity, neurotoxicity, embryotoxicity, reproductive system, breast, esophageal and lung toxicity. In relation to immunofluorescence analysis, biological processes related to AFB1- and OTA-toxicity were evaluated such as inflammation, neuronal differentiation, DNA damage, oxidative stress and cell death. In flow cytometry analysis, a wide range of assays have been performed across the reviewed studies being apoptosis assay, cell cycle analysis and intracellular ROS measurement the most employed. Although, the toxic effects of AFB1 and OTA have been reported, further research is needed to clarify AFB1 and OTA-mechanism of action on human health.

Antifungal and Antitoxigenic Effects of Selected Essential Oils in Vapors on Green Coffee Beans with Impact on Consumer Acceptability

The main objective of this study is to evaluate the effect of selected essential oils thyme chemotype linalool (Thymus zygis L.), thyme chemotype tymol (Thymus vulgaris L.), eucalyptus (Eucalyptus globulus Labill.), lavender (Lavandula angustifolia Mill.), mint (Mentha piperita L.), almond (Prunbus dulcis Mill.), cinnamon bark (Cinnamomum zeylanicum Nees), litsea (Litsea cubeba Lour. Pers), lemongrass (Cympogon citrati L. Stapf), and ginger (Zingiber officinalis Rosc.) in the vapor phase on growth, sporulation, and mycotoxins production of two Aspergillus strains (Aspergillus parasiticus CGC34 and Aspergillus ochraceus CGC87), important postharvest pathogens of green and roasted coffee beans. Moreover, the effect of the essential oils (EOs) on the sensory profile of the coffee samples treated with EOs was evaluated. The major components of tested EOs were determined by gas chromatography and mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). The results showed that almond, cinnamon bark, lemongrass, and litsea EOs are able to significantly inhibit the growth, sporulation, and mycotoxins production by toxigenic fungi. Sensory evaluation of coffee beans treated with EOs before and after roasting showed that some EOs (except lemongrass and litsea) do not adversely affect the taste and aroma of coffee beverages. Thus, application of the vapors of almond and cinnamon EOs appears to be an effective way that could serve to protect coffee during its transport and storage from toxigenic fungi.

Prevalence of toxigenic fungi and mycotoxins in Arabic coffee (Coffea arabica): Protective role of traditional coffee roasting, brewing and bacterial volatiles

Fungal infection and synthesis of mycotoxins in coffee leads to significant economic losses. This study aimed to investigate the prevalence of toxigenic fungi, their metabolites, and the effect of traditional roasting and brewing on ochratoxin A (OTA) and aflatoxins (AFs) contents of naturally contaminated coffee samples. In addition, in vivo biocontrol assays were performed to explore the antagonistic activities of Bacillus simplex 350–3 (BS350-3) on the growth and mycotoxins synthesis of Aspergillus ochraceus and A. flavus. The relative density of A. niger, A. flavus, Penicillium verrucosum and A. carbonarius on green coffee bean was 60.82%, 7.21%, 3.09% and 1.03%, respectively. OTA contents were lowest in green coffee beans (2.15 μg/kg), followed by roasted (2.76 μg/kg) and soluble coffee (8.95 μg/kg). Likewise, AFs levels were highest in soluble coffee (90.58 μg/kg) followed by roasted (33.61 μg/kg) and green coffee (9.07 μg/kg). Roasting naturally contaminated coffee beans at three traditional methods; low, medium and high, followed by brewing resulted in reduction of 58.74% (3.50 μg/kg), 60.88% (3.72 μg/kg) and 64.70% (4.11 μg/kg) in OTA and 40.18% (34.65 μg/kg), 47.86% (41.17 μg/kg) and 62.38% (53.73 μg/kg) AFs contents, respectively. Significant inhibitions of AFs and OTA synthesis by A. flavus and A. carbonarius, respectively, on infected coffee beans were observed in presence of Bacillus simplex BS350-3 volatiles. Gas chromatography mass spectrochemistry (GC-MS/MS) analysis of head-space BS350-3 volatiles showed quinoline, benzenemethanamine and 1-Octadecene as bioactive antifungal molecules. These findings suggest that marketed coffee samples are generally contaminated with OTA and AFs, with a significant level of roasted and soluble coffee contaminated above EU permissible limits for OTA. Further, along with coffee roasting and brewing; microbial volatiles can be optimized to minimize the dietary exposure to mycotoxins.

Evaluation of fungal contamination and ochratoxin A detection in different types of coffee by HPLC-based method

Background

Mycotoxins are secondary fungal metabolites that are produced by some toxigenic fungi on foodstuffs which are poisoning and potentiate for human's health hazards. In coffee samples, ochratoxin A and fungal contamination were examined.

Methods

Immunoaffinity columns were used for treating of all 50 samples from four types of coffee, after that high‐performance liquid chromatography was used for determining the amount of ochratoxin. For the identification of fungi, all coffee samples were cultured in appropriated media.

Results

The results showed that all samples were contaminated by ochratoxin A but only up to 50% of them had toxins higher than acceptable level as detected in black beans (47%), green beans (33.3%), torch (33.3%), and espresso (25%). Black coffee had a higher mean concentration of ochratoxin A than green coffee.

Conclusion

Predominant fungi isolated from coffee samples were Aspergillus species. Finally, careful monitoring of mycotoxins in coffee samples is essential to improve the quality of this favorable beverage in future.

Predictive Modeling and Validation on Growth, Production of Asexual Spores and Ochratoxin A of Aspergillus Ochraceus Group under Abiotic Climatic Variables

This study aimed to generate predictive models for growth, sporulation, and ochratoxin A (OTA) production under abiotic climatic variables, including temperatures (15-35 °C) and water activity levels (0.99-0.90 aw) by Aspergillus ochraceus group. The data were divided into three sets: one for training, one for testing, and the third one for model validation. Optimum growth occurred at 0.95 aw and 25 °C and 0.95 aw and 30 °C for A. westerdijkiae and A. steynii, respectively. Significantly improved A. westerdijkiae and A. steynii spore production occurred at 0.95 aw and 20 °C and 0.90 aw and 35 °C, respectively. A. steynii and A. westerdijkiae produced the majority of OTA at 35 °C and 0.95 aw and 25-30 °C at 0.95-0.99 aw, respectively. The accuracy of the third-order polynomial regression model reached 96% in growth cases, 94.7% in sporulation cases, and 90.9% in OTA production cases; the regression coefficients (R2) ranged from 0.8819 to 0.9978 for the Aspergillus ochraceus group. A reliable agreement was reached between the predicted and observed growth, sporulation, and OTA production. The effects of abiotic climatic variables on growth, sporulation, and OTA production of A. ochraceus group have been effectively defined, and the models generated were responsible for adequately predicted and validated models against data from other strains within A. ochraceus group that had been published in the literature under the current treatments. These models could be successfully implemented to predict fungal growth and OTA contamination on food matrices for these strains under these conditions.

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.

Molecular and HPLC-based approaches for detection of aflatoxin B1 and ochratoxin A released from toxigenic Aspergillus species in processed meat

BACKGROUND

Meat-products are considered an enriched media for mycotoxins. This study aimed to investigate the prevalence of toxigenic Aspergillus species in processed meat samples, HPLC-quantitative measurement of aflatoxin B1 and ochratoxin A residues, and molecular sequencing of aflR1 and pks genes. One hundred and twenty processed beef meat specimens (basterma, sausage, and minced meat; n = 40 for each) were collected from Ismailia Province, Egypt. Samples were prepared for total mold count, isolation, and identification of Aspergillus species. All samples were analyzed for the production of both Aflatoxin B1 and Ochratoxin A mycotoxins by HPLC. Molecular identification of Aspergillus flavus and Aspergillus ochraceus was performed using PCR amplification of the internal transcribed spacer (ITS) region; furthermore, the aflR1 and pks genes were sequenced.

RESULTS

The total mold count obtained from sausage samples was the highest one, followed by minced meat samples. The prevalence of A. flavus was (15%), (7.5%), and (10%), while the prevalence of A. ochraceus was (2.5%), (10%), and (0%) in the examined basterma, sausage, and minced meat samples, respectively. Using PCR, the ITS region was successfully amplified in all the tested A. flavus and A. ochraceus strains. Aflatoxin B1 was detected in six basterma samples (15%). Moreover, the ochratoxin A was detected only in four sausage samples (10%). The aflR1 and pks genes were amplified and sequenced successfully and deposited in the GenBank with accession numbers MF694264 and MF694264, respectively.

CONCLUSIONS

To the best of our knowledge, this is the first report concerning the HPLC-Molecular-based approaches for the detection of aflatoxin B1 and ochratoxin A in processed beef meat in Egypt. The production of aflatoxin B1 and ochratoxin A in processed meat constitutes a public health threat. Aflatoxin B1 is commonly associated with basterma samples. Moreover, ochratoxin A was detected frequently in sausage samples. The routine inspection of mycotoxins in processed meat products is essential to protect human consumers.

A PCR method to identify ochratoxin A-producing Aspergillus westerdijkiae strains on dried and aged foods

Ochratoxins are a group of mycotoxins that frequently occur as contaminants in agricultural commodities and foods, including dry-cured meats and cheeses. The fungus Aspergillus westerdijkiae is frequently isolated from aged foods and can produce ochratoxin A (OTA). However, individual strains of the fungus can have one of two OTA production phenotypes (chemotypes): OTA production and OTA nonproduction. Monitoring and early detection of OTA-producing fungi in food are the most effective strategies to manage OTA contamination. Therefore, we examined genome sequence data from five A. westerdijkiae strains isolated from the surface of cheese from southern Italy to identify genetic markers indicative of the twoOTA chemotypes. This analysis revealed a naturally occurring deletion of the OTA regulatory gene, otaR, in an OTA-nonproducing isolate.We used this information to design a polymerase chain reaction (PCR) method that could identify A. westerdijkiae and distinguish between the two OTA chemotypes. In this method, the PCR primers were complementary to conserved sequences flanking otaR and yielded different-sized amplicons from strains with the different chemotypes. The primers did not yield ota-region-specific amplicons from other OTA-producing species. Because the method is specific to A. westerdijkiae and can distinguish between the two OTA chemotypes, it has potential to significantly improve OTA monitoring programs.

Colorimetric and chemiluminescence based enzyme linked apta-sorbent assay (ELASA) for ochratoxin A detection

Ochratoxin A (OTA) is one of the most widespread mycotoxin found to contaminate various food products such as cereals, spices, groundnuts, coffee, wine, beer etc. It is also carried over from contaminated feed and fodder to milk, blood, meat, kidney and liver of animals consuming it. Enzyme-linked to biorecognition molecules like antibodies or aptamers are very popular due to their ability to be used as labels or tags in biosensing formats. In this work, OTA aptamer based colorimetric and chemiluminescence biosensing formats were evaluated for the detection of OTA. The colorimetric enzyme linked apta-sorbent assay (Co-ELASA) and chemiluminescence enzyme linked apta-sorbent assay (Cl-ELASA) showed a linear detection range from 1 pg/mL to 1 μg/mL with a limit of detection (LOD) of 0.84 pg/mL for Co-ELASA (limit of quantification (LOQ) = 2.54 pg/mL) and 1.29 pg/mL for Cl-ELASA (LOQ = 3.94 pg/mL) under optimized buffer conditions. Comparison of ELASA methods with sandwich ELISA indicated that the developed techniques had sensitivity similar to the conventional technique which indicated a LOD of 1.13 pg/mL and LOQ of 3.41 pg/mL. Studies in simulated contaminated food samples by spiking OTA in groundnut and coffee bean at concentrations of 0.1, 1 and 10 ppb, indicated recoveries in the range of 50.21 to 113.27% for Co-ELASA, 90.47 to 107.72% for Cl-ELASA and 76.23 to 141.49% for ELISA. Results of the study indicate that Co-ELASA and Cl-ELASA assays could be an alternate approach for ultrasensitive detection of OTA in food samples, which can also be adapted for biosensor development.

The Genomic Regions That Contain Ochratoxin A Biosynthetic Genes Widely Differ in Aspergillus Section Circumdati Species

Aspergillus section Circumdati includes 27 species, some of which are considered ochratoxin A (OTA) producers. However, there is considerable controversy about their potential OTA synthesis ability. In this work, the complete genomes of 13 species of Aspergillus section Circumdati were analyzed in order to study the cluster of OTA biosynthetic genes and the region was compared to those previously reported in A. steynii and A. westerdijkiae. The results obtained reveal that the genomes of some species in this section, including A. affinis, A. cretensis, A. elegans, A. muricatus, A. pulvericola, A. roseoglobulosus, and A. subramanianii, contain a potentially functional OTA biosynthetic cluster. Therefore, they might be able to synthesize the toxin. On the contrary, A. melleus, A. ochraceus, A. ostianus, A. persii, A. sclerotiorum, A. sesamicola, and A. westlandensis contain a truncated version of the cluster that lacks many of the genes involved in OTA biosynthesis, which might be related to their inability to produce OTA. The gain/loss pattern is different in all species, which suggests that the genetic evolution of this region might be due to independent events.

Potential Control of Mycotoxigenic Fungi and Ochratoxin A in Stored Coffee Using Gaseous Ozone Treatment

The objective of this study was to examine the effect of treatment of Arabica green coffee beans with gaseous ozone (O₃) for the control of ochratoxigenic fungi and ochratoxin A (OTA) contamination by Aspergillus westerdijkiae, A. ochraceus, and A. carbonarius during storage. Studies included (i) relative control of the populations of each of these three species when inoculated on irradiated green coffee beans of different initial water availabilities using 400 and 600 ppm gaseous O₃ treatment for 60 min at a flow rate of 6 L⁻¹ and on OTA contamination after 12 days storage at 30 °C and (ii) effect of 600 ppm O₃ treatment on natural populations of green stored coffee beans at 0.75, 0.90, and 0.95 water activity (a_w) or with additional inoculum of a mixture of these three ochratoxigenic fungi after treatment and storage for 12 days at 30 °C on fungal populations and OTA contamination. Exposure to 400 and 600 ppm O₃ of coffee beans inoculated with the toxigenic species showed that there was less effect on fungal populations at the lowered a_w (0.75). However, toxigenic fungal populations significantly increased 48 h after exposure and when stored at 0.90 and 0.95 a_w for 12 days. All three species produced high amounts of OTA in both O₃ treatments of the wetter coffee beans at 0.90 and 0.95 a_w. Gaseous O₃ (600 ppm) treatment of naturally contaminated green coffee beans had little effect on fungal populations after treatment, regardless of the initial a_w level. However, after storage, there was some reduction (26%) observed in coffee at 0.95 a_w. In addition, no fungal populations or OTA contamination occurred in the 0.75 and 0.90 a_w treatments after exposure to 600 ppm gaseous O₃ and storage for 12 days. It appears that under wetter conditions (≥0.90–95 a_w) it is unlikely that fungal populations and OTA contamination of stored coffee beans, even with such high O₃ concentrations would be controlled. The results are discussed in the context of potential application of O₃ as an intervention system for stored coffee post-fermentation and during medium term storage and transport.

Resilience of Aspergillus westerdijkiae Strains to Interacting Climate-Related Abiotic Factors: Effects on Growth and Ochratoxin A Production on Coffee-Based Medium and in Stored Coffee

We examined the resilience of strains of Aspergillus westerdijkiae in terms of growth and ochratoxin A (OTA) production in relation to: (a) two-way interacting climate-related abiotic factors of water activity (aw, 0.99-0.90) × temperature (25-37 °C) on green coffee and roasted coffee-based media; (b) three-way climate-related abiotic factors (temperature, 30 vs. 35 °C; water stress, 0.98-0.90 aw; CO2, 400 vs. 1000 ppm) on growth and OTA production on a 6% green coffee extract-based matrix; and (c) the effect of three-way climate-related abiotic factors on OTA production in stored green coffee beans. Four strains of A. westerdijkiae grew equally well on green or roasted coffee-based media with optimum 0.98 aw and 25-30 °C. Growth was significantly slower on roasted than green coffee-based media at 35 °C, regardless of aw level. Interestingly, on green coffee-based media OTA production was optimum at 0.98-0.95 aw and 30 °C. However, on roasted coffee-based media very little OTA was produced. Three-way climate-related abiotic factors were examined on two of these strains. These interacting factors significantly reduced growth of the A. westerdijkiae strains, especially at 35 °C × 1000 ppm CO2 and all aw levels when compared to 30 °C. At 35 °C × 1000 ppm CO2 there was some stimulation of OTA production by the two A. westerdijkiae strains, especially under water stress. In stored green coffee beans optimum OTA was produced at 0.95-0.97 aw/30 °C. In elevated CO2 and 35 °C, OTA production was stimulated at 0.95-0.90 aw.