Production of ochratoxin A by Aspergillus carbonarius on coffee cherries

Biocontrol activities of yeasts or lactic acid bacteria isolated from Robusta coffee against Aspergillus carbonarius growth and ochratoxin A production in vitro

Biocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.

Exploring the microbiome of coffee plants: Implications for coffee quality and production

Coffee stands as one of the world's most popular beverages, and its quality undergoes the influence of numerous pre- and post-harvest procedures. These encompass genetic variety, cultivation environment, management practices, harvesting methods, and post-harvest processing. Notably, microbial communities active during fermentation hold substantial sway over the ultimate quality and sensory characteristics of the final product. The interaction between plants and microorganisms assumes critical significance, with specific microbes assuming pivotal roles in coffee plant growth, fruit development, and, subsequently, the fruit's quality. Microbial activities can synthesize or degrade compounds that influence the sensory profile of the beverage. However, studies on the metabolic products generated by various coffee-related microorganisms and their chemical functionality, especially in building sensory profiles, remain scarce. The primary aim of this study was to conduct a literature review, based on a narrative methodology, on the current understanding of the plant-microorganism interaction in coffee production. Additionally, it aimed to explore the impacts of microorganisms on plant growth, fruit production, and the fermentation processes, directly influencing the ultimate quality of the coffee beverage. Articles were sourced from ScienceDirect, Scopus, Web of Science, and Google Scholar using specific search terms such as "coffee microorganisms", "microorganisms-coffee interactions", "coffee fermentation", "coffee quality", and 'coffee post-harvest processing". The articles used were published in English between 2000 and 2023. Selection criteria involved thoroughly examining articles to ensure their inclusion was based on results about the contribution of microorganisms to both the production and quality of the coffee beverage. The exploration of microorganisms associated with the coffee plant and its fruit presents opportunities for bioprospecting, potentially leading to targeted fermentations via starter cultures, consequently generating new profiles. This study synthesizes existing data on the current understanding of the coffee-associated microbiome, its functionalities within ecosystems, the metabolic products generated by microorganisms, and their impacts on fermentation processes and grain and beverage quality. It highlights the importance of plant-microorganism interactions in the coffee production chain.

Coffee Microbiota and Its Potential Use in Sustainable Crop Management. A Review

Intensive coffee production is accompanied by several environmental issues, including soil degradation, biodiversity loss, and pollution due to the wide use of agrochemical inputs and wastes generated by processing. In addition, climate change is expected to decrease the suitability of cultivated areas while potentially increasing the distribution and impact of pests and diseases. In this context, the coffee microbiota has been increasingly studied over the past decades in order to improve the sustainability of the coffee production. Therefore, coffee associated microorganisms have been isolated and characterized in order to highlight their useful characteristics and study their potential use as sustainable alternatives to agrochemical inputs. Indeed, several microorganisms (including bacteria and fungi) are able to display plant growth-promoting capacities and/or biocontrol abilities toward coffee pests and diseases. Despite that numerous studies emphasized the potential of coffee-associated microorganisms under controlled environments, the present review highlights the lack of confirmation of such beneficial effects under field conditions. Nowadays, next-generation sequencing technologies allow to study coffee associated microorganisms with a metabarcoding/metagenomic approach. This strategy, which does not require cultivating microorganisms, now provides a deeper insight in the coffee-associated microbial communities and their implication not only in the coffee plant fitness but also in the quality of the final product. The present review aims at (i) providing an extensive description of coffee microbiota diversity both at the farming and processing levels, (ii) identifying the “coffee core microbiota,” (iii) making an overview of microbiota ability to promote coffee plant growth and to control its pests and diseases, and (iv) highlighting the microbiota potential to improve coffee quality and waste management sustainability.

Intraspecific variability of growth and ochratoxin A production by Aspergillus carbonarius from different foods and geographical areas

Ochratoxin A (OTA) is a nephrotoxic mycotoxin naturally found in a wide range of food commodities throughout the world. Aspergillus carbonarius is the most important source of OTA in food commodities such as wine, grapes and dried vine fruits and is also responsible for the formation of OTA in coffee. The aim of this study was to determine the simultaneous effect of three culture media (Czapek Yeast Extract Broth (CYB); Synthetic Grape Juice Medium (SGM) and White grape juice (WGJ)) at three water activity (a_w) levels (0.90; 0.95 and 0.98-0.99), and three incubation temperatures (15 °C, 25 °C and 35 °C) on the growth and OTA production by 16 strains of A. carbonarius. The strains were mainly isolated from grapes from areas with a Mediterranean climate. All the strains were confirmed for identity by sequencing of the calmodulin gene. The assay was performed in microtiter plates, determining the absorbance at 530 nm and the concentration of OTA after 1, 2, 4 and 10 days of incubation. No significant differences were observed in absorbance values between the strains. The highest absorbance values were recorded in CYB at 0.99 a_w and at 0.95 a_w after 10 days of incubation at 25 °C and 35 °C. None of the strains were able to grow at 0.90 a_w and 15 °C in any culture media after 10 days of incubation. OTA concentration was statistically higher at 15 °C than at 25 °C or 35 °C. The highest significant OTA values were obtained at 0.98-0.99 a_w and the best culture media for OTA production was CYB, followed by WGJ and SGM. While strains isolated from Mediterranean climate foods had a similar behavior despite being isolated from different geographical areas, OTA concentration produced by one Robusta coffee strain from Thailand was statistically higher at 25 °C than at 15 °C. This would suggest that the type of food matrices and consequently the adaptation of A. carbonarius strains to different climatic conditions would have a greater influence on the ecophysiology of the strains than only their geographical origin.

Real-time PCR-based method for rapid detection of Aspergillus niger and Aspergillus welwitschiae isolated from coffee

Some species from Aspergillus section Nigri are morphologically very similar and altogether have been called A. niger aggregate. Although the species included in this group are morphologically very similar, they differ in their ability to produce mycotoxins and other metabolites and their taxonomical status has evolved continuously. Among them, A. niger and A. welwitschiae are ochratoxin A and fumonisin B₂ producers and their detection and/or identification is of crucial importance for food safety. The aim of this study was the development of a real-time PCR-based method for simultaneous discrimination of A. niger and A. welwitschiae from other species of the A. niger aggregate isolated from coffee beans. One primer pair and a hybridization probe specific for detection of A. niger and A. welwitschiae strains were designed based on the BenA gene sequences, and used in a Real-time PCR assay for the rapid discrimination between both these species from all others of the A. niger aggregate. The Real-time PCR assay was shown to be 100% efficient in discriminating the 73 isolates of A. niger/A. welwitschiae from the other A. niger aggregate species analyzed as a negative control. This result testifies to the use of this technique as a good tool in the rapid detection of these important toxigenic species.

Incidence of Mycotoxins in Local and Branded Samples of Chocolates Marketed in Pakistan

The present overview was intended to evaluate the degree of total aflatoxins and ochratoxin A contamination in different samples of bitter, dark, milk, and white chocolates marketed in Pakistan. For that exploration, two hundred (n=200) samples of chocolates, 100 branded and 100 local, were analyzed for mycotoxins profile by HPLC-FLD. The outcomes firmly sustained that the majority of the samples were contaminated with aflatoxins and ochratoxin A. The incidence of total aflatoxins and ochratoxin A in branded samples was 83% and 90%, whereas the local samples showed 91% and 97% contamination, respectively. The highest amount of total aflatoxins was found in branded dark chocolates, that is, 2.27 μg/kg, and maximum ochratoxin A level was detected white chocolates (2.06 μg/kg). On average, the local white chocolates and dark chocolates faced the highest level of total aflatoxins (3.35 μg/kg) and ochratoxin A (3.48 μg/kg), respectively. The local samples of chocolates were more contaminated with mycotoxins as compared to branded ones accredited to the lack of quality control and quality assurance during the manufacturing as well as packing processes. In recent years, consumption of chocolate is rapidly increasing especially by young generation, so monitoring of mycotoxin occurrence in them is a matter of great concern and more studies are required to comprehend the production of mycotoxins in these products.

Aspergillus Species and Their Associated Mycotoxins

The genus Aspergillus is among the most abundant and widely distributed organism on earth, and at the moment comprises 339 known species. It is one of the most important economically fungal genus and the biotechnological use of Aspergillus species is related to production of soy sauce, of different hydrolytic enzymes (amylases, lipases) and organic acid (citric acid, gluconic acid), as well as biologically active metabolites such as lovastatin. Although they are not considered to be major cause of plant diseases, Aspergillus species are responsible for several disorders in various plants and plant products, especially as opportunistic storage moulds. The notable consequence of their presence is contamination of foods and feeds by mycotoxins, among which the most important are aflatoxins, ochratoxin A, and, at a less extent, fumonisins. Aflatoxins B₁, B₂, G₁, G₂ are the most toxic and carcinogenic mycotoxins, due to their extreme hepatocarcinogenicity; ochratoxin A is a potent nephrotoxin, it is also carcinogenic, teratogenic, and immunotoxic in rats and possibly in humans; fumonisins are hepatotoxic and nephrotoxic with potential carcinogenic effects on rat and mice. In this chapter we summarize the main aspects of morphology, ecology, epidemiology, and toxigenicity of Aspergillus foodborne pathogens which belong to sections Flavi, Circumdati, and Nigri, occurring in several agricultural products and responsible of aflatoxin, ochratoxin A, and fumonisins contamination of food and feed.

Fungal contamination in green coffee beans samples: A public health concern

Studies on the microbiology of coffee cherries and beans have shown that the predominant toxigenic fungal genera (Aspergillus and Penicillium) are natural coffee contaminants. The aim of this study was to investigate the distribution of fungi in Coffea arabica L. (Arabica coffee) and Coffea canephora L. var. robusta (Robusta coffee) green coffee samples obtained from different sources at the pre-roasting stage. Twenty-eight green coffee samples from different countries of origin (Brazil, Timor, Honduras, Angola, Vietnam, Costa Rica, Colombia, Guatemala, Nicaragua, India, and Uganda) were evaluated. The fungal load in the contaminated samples ranged from 0 to 12330 colony forming units (CFU)/g, of which approximately 67% presented contamination levels below 1500 CFU/g, while 11% exhibited intermediate contamination levels between 1500 and 3000 CFU/g. Contamination levels higher than 3000 CFU/g were found in 22% of contaminated coffee samples. Fifteen different fungi were isolated by culture-based methods and Aspergillus species belonging to different sections (complexes). The predominant Aspergillus section detected was Nigri (39%), followed by Aspergillus section Circumdati (29%). Molecular analysis detected the presence of Aspergillus sections Fumigati and Circumdati. The% coffee samples where Aspergillus species were identified by culture-based methods were 96%. Data demonstrated that green coffee beans samples were contaminated with toxigenic fungal species. Since mycotoxins may be resistant to the roasting process, this suggests possible exposure to mycotoxins through consumption of coffee. Further studies need to be conducted to provide information on critical points of coffee processing, such that fungal contamination may be reduced or eliminated and thus exposure to fungi and mycotoxins through coffee handling and consumption be prevented.

Nanobody-based enzyme immunoassay for ochratoxin A in cereal with high resistance to matrix interference

A sensitive indirect competitive nanobody-based enzyme linked immunosorbent assay (Nb-ELISA) for ochratoxin A (OTA) with high resistance to cereal matrix interference was developed. Nanobodies against OTA (Nb15, Nb28, Nb32, Nb36) were expressed in E. coli cells and their thermal stabilities were compared with that of an OTA-specific monoclonal antibody 6H8. All nanobodies could still retain their antigen-binding activity after exposure to temperature 95°C for 5min or to 90°C for 75min. Nb28 that exhibited the highest sensitivity in ELISA was selected for further research. An indirect competitive ELISA based on Nb28 was developed for OTA, with an IC₅₀ of 0.64ng/mL and a linear range (IC₂₀-IC₈₀) of 0.27-1.47ng/mL. Cereal samples were analyzed following a 2.5 fold dilution of sample extracts, showing the good resistance to matrix interference of the Nb-ELSIA. The recovery of spiked cereal samples (rice, oats, barley) ranged from 80% to 105% and the Nb-ELISA results of OTA content in naturally contamined samples were in good agreement with those determined by a commercial ELISA kit. The results indicated the reliablity of nanobody as a promising immunoassay reagent for detection of mycotoxins in food matrix and its potential in biosensor development.

Influence of temperature, water activity and incubation time on fungal growth and production of ochratoxin A and zearalenone by toxigenic Aspergillus tubingensis and Fusarium incarnatum isolates in sorghum seeds

The major objective of this study was to describe the effect of water activity and temperature on radial growth and production of ochratoxin A (OTA) and zearalenone (ZEA) on sorghum grains of three Aspergillus tubingensis and three Fusarium incarnatum isolates. The water activity range was 0.91-0.99 a_w for F. incarnatum isolates and 0.88-0.99 a_w for A. tubingensis isolates. Temperatures of incubation were 15, 25 and 37°C for both species. Mycotoxin production was determined after 7, 14, 21 and 28days depending on the growth rate of the six isolates. Maximum growth rates (mm/day) were observed at 37°C and 0.99 a_w for A. tubingensis isolates and at 0.99 a_w and 25°C for F. incarnatum isolates. A. tubingensis was able to grow at 15°C only at the highest a_w levels (0.97 and 0.99 a_w). However, at this temperature F. incarnatum grew at 0.94 a_w. Optimum ochratoxin A production was observed at 0.97 a_w×37°C whereas optimal conditions for ZEA production varied from one isolate to another. Moreover, isolates of F. incarnatum from Tunisia do not require high a_w and temperature levels to yield maximum levels of ZEA. In general, our results showed that there is no correlation between the growth and production of ZEA in the case of F. incarnatum. This is the first study on the water activity and temperature effect on growth rate and ZEA production of F. incarnatum. Our results show that sorghum grains not only support growth but also OTA and ZEA production by A. tubingensis and F. incarnatum, respectively.

Occurrence of Ochratoxigenic Fungi and Ochratoxin A in Green Coffee from Different Origins

Fungal infection and ochratoxin A (OTA) contamination were determined in green coffee samples from different origins, in which OTA-producing fungi were also identified. About 72% of the beans analysed by direct plating presented fungal infection, including species of Aspergillus, Penicillium and Rhizopus. The genus Aspergillus was presented in more than 90% of infected coffee beans. Aspergillus ochraceus and Aspergillus section Nigri isolates represented 2.8 and 65.4%, respectively from the total number of isolates from the coffee beans. The capacity to produce OTA was determined in 260 isolates of A. section Nigri and 19 of A. ochraceus by the agar plug method, giving positive results for 6% of the A. section Nigri isolates and 16% of the A. ochraceus. OTA production was analysed by high performance liquid chromatography. OTA contamination of green coffee beans was analysed by enzyme immunoassay. OTA levels in all samples analysed were above the limit of detection (0.6 mg/kg), with a mean OTA concentration of 6.7 mg/kg.

Advances in Mycotoxin Research: Public Health Perspectives

Aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause serious adverse effects in different organs including the liver, kidney, and immune system in humans. These toxic secondary metabolites are produced by filamentous fungi mainly in the genus Aspergillus, Penicillium, and Fusarium. It is challenging to control the formation of mycotoxins due to the worldwide occurrence of these fungi in food and the environment. In addition to raw agricultural commodities, mycotoxins tend to remain in finished food products as they may not be destroyed by conventional processing techniques. Hence, much of our concern is directed to chronic health effects through long-term exposure to one or multiple mycotoxins from contaminated foods. Ideally risk assessment requires a comprehensive data, including toxicological and epidemiological studies as well as surveillance and exposure assessment. Setting of regulatory limits for mycotoxins is considered necessary to protect human health from mycotoxin exposure. Although advances in analytical techniques provide basic yet critical tool in regulation as well as all aspects of scientific research, it has been acknowledged that different forms of mycotoxins such as analogs and conjugated mycotoxins may constitute a significant source of dietary exposure. Further studies should be warranted to correlate mycotoxin exposure and human health possibly via identification and validation of suitable biomarkers.

What's Inside That Seed We Brew? A New Approach To Mining the Coffee Microbiome

Coffee is a critically important agricultural commodity for many tropical states and is a beverage enjoyed by millions of people worldwide. Recent concerns over the sustainability of coffee production have prompted investigations of the coffee microbiome as a tool to improve crop health and bean quality. This review synthesizes literature informing our knowledge of the coffee microbiome, with an emphasis on applications of fruit- and seed-associated microbes in coffee production and processing. A comprehensive inventory of microbial species cited in association with coffee fruits and seeds is presented as reference tool for researchers investigating coffee-microbe associations. It concludes with a discussion of the approaches and techniques that provide a path forward to improve our understanding of the coffee microbiome and its utility, as a whole and as individual components, to help ensure the future sustainability of coffee production.

Deletion of glucose oxidase changes the pattern of organic acid production in Aspergillus carbonarius

Aspergillus carbonarius has potential as a cell factory for the production of different organic acids. At pH 5.5, A.carbonarius accumulates high amounts of gluconic acid when it grows on glucose based medium whereas at low pH, it produces citric acid. The conversion of glucose to gluconic acid is carried out by secretion of the enzyme, glucose oxidase. In this work, the gene encoding glucose oxidase was identified and deleted from A. carbonarius with the aim of changing the carbon flux towards other organic acids. The effect of genetic engineering was examined by testing glucose oxidase deficient (Δgox) mutants for the production of different organic acids in a defined production medium. The results obtained showed that the gluconic acid accumulation was completely inhibited and increased amounts of citric acid, oxalic acid and malic acid were observed in the Δgox mutants.

Ochratoxin A: developmental and reproductive toxicity-an overview

Ochratoxin A (OTA) is nephrotoxic, hepatotoxic, reprotoxic, embryotoxic, teratogenic, neurotoxic, immunotoxic, and carcinogenic for laboratory and farm animals. Male and female reproductive health has deteriorated in many countries during the last few decades. A number of toxins in environment are suspected to affect reproductive system in male and female. OTA is one of them. OTA has been found to be teratogenic in several animal models including rat, mouse, hamster, quail, and chick, with reduced birth weight and craniofacial abnormalities being the most common signs. The presence of OTA also results in congenital defects in the fetus. Neither the potential of OTA to cause malformations in human nor its teratogenic mode of action is known. Exposure to OTA leads to increased embryo lethality manifested as resorptions or dead fetuses. The mechanism of OTA transfer across human placenta (e.g., which transporters are involved in the transfer mechanism) is not fully understood. Some of the toxic effects of OTA are potentiated by other mycotoxins or other contaminants. Therefore, OTA exposure of pregnant women should be minimized. OTA has been shown to be an endocrine disruptor and a reproductive toxicant, with abilities of altering sperm quality. Other studies have shown that OTA is a testicular toxin in animals. Thus, OTA is a biologically plausible cause of testicular cancer in man.

Ochratoxigenic fungi associated with green coffee beans (Coffea arabica L.) in conventional and organic cultivation in Brazil

The genera Aspergillus comprises species that produce mycotoxins such as aflatoxins, ochratoxins and patulin. These are cosmopolitan species, natural contaminants of agricultural products. In coffee grains, the most important Aspergillus species in terms of the risk of presenting mycotoxins belong to the genera Aspergillus Section Circumdati and Section Nigri. The purpose of this study was to assess the occurrence of isolated ochratoxigenic fungi of coffee grains from organic and conventional cultivation from the South of Minas Gerais, Brazil, as well as to evaluate which farming system presents higher contamination risk by ochratoxin A (OTA) produced by fungi. Thirty samples of coffee grains (Coffea arabica L.) were analysed, being 20 of them of conventional coffee grains and 10 of them organic. The microbiological analysis was done with the Direct Plating Technique in a Dichloran Rose Bengal Chloramphenicol Agar (DRBC) media. The identification was done based on the macro and micro morphological characteristics and on the toxigenic potential with the Plug Agar technique. From the 30 samples analysed, 480 filamentous fungi of the genera Aspergillus of the Circumdati and Nigri Sections were isolated. The ochratoxigenic species identified were: Aspergillus auricoumus, A. ochraceus, A. ostianus, A. niger and A. niger Aggregate. The most frequent species which produces ochratoxin A among the isolated ones was A. ochraceus, corresponding to 89.55%. There was no significant difference regarding the presence of ochratoxigenic A. ochreceus between the conventional and organic cultivation systems, which suggests that the contamination risk is similar for both cultivation systems.

A gene cluster of the ochratoxin A biosynthetic genes inPenicillium

A putative ochratoxin A (OTA) biosynthetic gene cluster inP. nordicum has been identified. The first part of the gene cluster is located on a DNA fragment of 10 kb in length and harbours three genes. A gene with high homology to an alkaline serine protease gene (accession number AY557343), which represents the upstream border of the cluster. Furthermore the fragment carries a large part (about 2 kb) of the 5' end of a polyketide synthase (otapksPN, accession number AY196315) and a complete non-ribosomal peptide synthetase (otanpsPN, accession number AY534879). The second part of the cluster is located on a 4.3 kb fragment that harbours three open reading frames (ORFs) encoding putative OTA biosynthetic proteins: one incomplete ORF at the 5' end of the fragment demonstrated homology to an organic anion transporter from rat kidneys (otatraPN). This transporter has been described to be responsible for the transport of toxic OTA out of the cell. One complete ORF of 951 nucleotides is also located on this fragment. This gene has limited homology to a chloroperoxidase fromGluconobacter oxidans. At the 3' end of this DNA fragment is an incomplete open reading frame of a potential nitrate transporter. The transcription of all putative OTA biosynthetic genes is increased under OTA conducive conditions. The expression kinetics of the genes resembles that of secondary metabolite biosynthetic genes, in which these genes are co-ordinately expressed during the late growth phase.PCR analysis demonstrated that the gene cluster is only present in the two ochratoxin A producingPenicillium species,P. verrucosum andP. nordicum. P. nalgiovense, a species occurring in the same habitat asP. nordicum carries inactive homologues of the genes. All other species proved to be negative for the genes. This was also true for OTA producing Aspergilli.

Mycotoxin production by Aspergillus niger aggregate strains isolated from harvested maize in three Portuguese regions

BACKGROUND

Maize is considered one of the crops more susceptible to mycotoxins in the world. Two of the mycotoxins commonly associated with maize are fumonisins and ochratoxin A. Aspergillus niger is a known producer of ochratoxin A and is easily found in maize. Recently, however, A. niger has been reported to produce as well fumonisins, mainly fumonisin B(2).

AIMS

The aim of this study was to isolate A. niger strains from maize samples collected in three Portuguese maize growing regions and to detect the production of both fumonisin B(2) and ochratoxin A.

METHODS

Ninety five maize samples were collected, plated, and all observable Aspergillus section Nigri strains were isolated. Strains were morphologically characterized and mycotoxin production was determined by HPLC-FD.

RESULTS

Isolations resulted in a total of 270 strains of black Aspergillus from 73 samples (77% of the samples). About 14% of those strains were found to produce ochratoxin A and 39% of the strains were found to produce fumonisin B(2).

CONCLUSIONS

An association between the production of these two mycotoxins could not be found and no conclusions could be taken whether the presence of A. niger aggregate strains will increase the risk of maize contamination with fumonisins and more specifically with fumonisin B(2).

Effect of Robusta (Coffea canephora P.) coffee cherries quantity put out for sun drying on contamination by fungi and ochratoxin A (OTA) under tropical humid zone (Côte d'Ivoire)

The effect of coffee cherries quantity put out for sun drying on the kinetics of the drying, chemical components variation, fungal growth and ochratoxin A production was evaluated. The results showed that the more coffee cherries quantity on the drying area was important, the slower they dried. Indeed, the drying durations were 12, 17, 21, 26, 31 and 32 days respectively for the lots of 10 kg, 20 kg, 30 kg, 40 kg, 50 kg and 60 kg of cherries by square meter of drying area. The slowness of the drying led to the increasing of fungal development and ochratoxin A production in the cherries. Indeed, samples more contaminated were those from the lots of 50 kg and 60 kg of cherries by square meter of drying area with between 10% and 100% of infected beans and with levels of ochratoxin A ranging from 0.92 to 118.47 and 1.4 to 131.33 μg kg(-1) respectively. The slowness of the drying led also to the acidification of the cherries (pH=5.55-4.54) and the degradation of their chlorogenic acids content (13.03-11.69) while for their caffeine content (2.52-2.54), any significant difference was observed whatever the drying duration.

The effects of different ecophysiological factors on ochratoxin A production

Mycotoxin biosynthesis is affected by peculiar agro-ecosystem dependent conditions. Accordingly, the correlation between mycotoxin contamination and environmental condition change scenarios should be carefully considered. This is because fungal colonization and mycotoxin contamination could critically impair the availability of food products, especially in poor countries. At any time, the agricultural products might become susceptible to fungal contamination and mycotoxin production in uncontrolled storage. From 2000 to 2010, many studies were carried out in the case of the effects of different parameters on ochratoxin A (OTA) production by fungi in order to avoid providing the appropriate conditions for producing OTA. Water activity (a(w)), temperature, type of species and the substrates were introduced as the most important in these articles. This paper reviews the major published articles regarding the different ecophysiological factors influencing on OTA production.

Mycobiota and aflatoxin B1 in feed for farmed sea bass (Dicentrarchus labrax)

Thesafety characteristics of feed used in fish and crustacean aquaculture systems are an essential tool to assure the productivity of those animal exploitations. Safety of feed may be affected by different hazards, including biological and chemical groups. The aim of this preliminary study was to evaluate fungi contamination and the presence of aflatoxins in 87 samples of feed for sea bass, collected in Portugal. Molds were found in 35 samples (40.2%) in levels ranging from 1 to 3.3 log10 CFU∙g⁻¹. Six genera of molds were found. Aspergillus flavus was the most frequent, found in all positive samples, with a range from 2 to 3.2 log₁₀ CFU∙g⁻¹. Aspergillus niger was found in 34 samples (39.1%), ranging from 1 to 2.7 log₁₀ CFU∙g⁻¹. Aspergillus glaucus was found in 26 samples (29.9%) with levels between 1 and 2.4 log₁₀ CFU∙g⁻¹. Penicillium spp. and Cladosporium spp. were both found in 25 samples (28.7%). Fusarium spp. was found in 22 samples (25.3%), ranging from 1 to 2.3 log₁₀ CFU∙g⁻¹. All feed samples were screened for aflatoxins using a HPLC technique, with a detection limit of 1.0 μg∙kg⁻¹. All samples were aflatoxin negative.

Ecophysiology of Aspergillus section nigri species potential ochratoxin a producers

After aflatoxins, ochratoxin A (OTA) is the most studied mycotoxin due to the toxicological significance in human and animal diets. OTA presence has been extensively reported worldwide in the last decade in several agricultural products. The main OTA producer in tropical and temperate climates is Aspergillus carbonarius followed by species belonging to A. niger aggregate. Currently, many scientists worldwide have studied the influence of water activity and temperature for growth and biosynthesis of OTA by these species on synthetic media. This article reviews ecophysiological studies of Aspergillus section Nigri strains on synthetic media and natural substrates. The results of these investigations suggest that significant amounts of OTA can be produced in only five days and that the use of different storage practices, such as a(W) and temperature levels below 0.930 and 15 °C, respectively, allow controlling fungal contamination and minimizing the OTA production in several products as peanuts, corn, dried grapes and derived products for human consumption.

Determination of Patulin and Ochratoxin A using HPLC in apple juice samples in Saudi Arabia

Although, Patulin and Ochratoxin are produced by the same genera of molds, however, Patulin was the most extensively studied mycotoxins in apple juice and no reports have explored the presence of Ochratoxin A in the apple juice. Therefore, the objective of this study was to explore the presence of Patulin and Ochratoxin A in apple juice in Saudi Arabian market of Jeddah. Potato dextrose agar(PDA) was used to detect fungal contamination. Patulin was determined using HPLC equipped with a UV detector set at 276 nm. Also, HPLC with fluorescence detector was set at 333 and 420 nm as excitation and emission wavelength, respectively,was used for Ochratoxin A separation. All samples of apple juice were free from fungi and yeasts. The Patulin (PAT) was detected in only one type out of 17 types (5.88%) with a concentration of 152.5 ppb, (305%) increased compared with the maximum permitted level (50 ppb). However the occurrence of Ochratoxin A (OTA) in apple juice samples was discovered in 5 types out of 17 types (29.41%). The concentration of OTA ranged from 100 to 200 ppb reaching 5-10-folds compared with the permissible limits (20 ppb).

Impact of drying surface and raking frequencies on mold incidence, ochratoxin A contamination, and cup quality during preparation of arabica and robusta cherries at the farm level

The aim of this study was to evaluate the impact and contribution of various drying surfaces (soil, cement, and tarpaulin) and raking frequencies (1 and 4/day) on the incidence of toxigenic molds, ochratoxin A (OTA) production, and on the overall cup quality during preparation of arabica and robusta coffee cherry in India. Two individual experimental batches (run 1 at the begin of harvest and run 2 at the end of harvest) were set up for the study. Results showed high incidence of molds in coffee dried on soil surface compared with that on cement and tarpaulin surfaces. In both arabica and robusta, OTA could be detected in Aspergillus ochraceus contaminated samples at the end of harvest. Raking of the cherries 4 times/day showed lower fungal incidence with no OTA levels detected. Overall, coffee cherry prepared by drying on tarpaulin surface with 4 rakings/day showed lower OTA and fungal incidence with good and acceptable cup quality, and this is recommended to be practiced at the farm level.