A sub‐Saharan African perspective on mycotoxins in beer – a review

Beer is an alcoholic beverage made from a cereal grain extract and is widely consumed in sub‐Saharan Africa and the world at large. However, beer consumption could expose consumers to mycotoxins. In this review, we appraised the different mycotoxins associated with beer contamination, elucidating their structures and incidence in cereals involved in beer production. The common mycotoxins that are found within the brewing process are reviewed. These include aflatoxin B₁ (AFB₁), fumonisin (FB), ochratoxin A (OTA), zearalenone (ZEA) and deoxynivalenol (DON), which are the prime contaminants in beer produced in sub‐Saharan Africa. Residual levels of <20% of AFB₁, OTA and FB₂ together with the transformation of ZEA (into a less toxic compound β‐zearalenol) can be achieved during the production of beers originating from Europe/America, while >50% of DON and higher ratios of FB₁ can be recovered in finished beer. Adsorption is the major means of mycotoxin removal during beer production. In contrast, traditional African beer processes show no significant efficient removal of mycotoxins. This is because the prevailing environmental conditions during beer production are favourable to mycotoxigenic fungal proliferation. This subsequently leads to relatively high concentration of mycotoxins in freshly processed beer, with a possible increase during the beer shelf‐life owing to the absence of appropriate microbial stabilisation treatments in the finished processed beer. © 2019 The Institute of Brewing & Distilling     

Retention of ochratoxin A and fumonisin B1 and B2 from beer on solid surfaces: comparison of efficiency of adsorbents with different origin

Fifteen solid materials with variable origin and various adsorption properties for retention of mycotoxins were tested—mineral materials, organic polymers and chemical modified silica gels that are used in widespread separation techniques. Some filtration materials currently utilized in brewing technology for beer clarifying and filtration were also examined. Adsorbents have been investigated in model and real samples (beer) and evaluated on the basis of adsorption capacity for ochratoxin A and fumonisin B1 and B2. Mentioned mycotoxins are commonly present in beers and may increase the risk on human health in high beer-consuming countries. The ability of adsorbent to retain mycotoxins on its surface was evaluated as micrograms of mycotoxin per one gram of adsorbent or as percentage of mycotoxin adsorbed. The experiments were accomplished in dynamic mode, which is mostly applied in beer production. The quality profile of beer after treatment with adsorbents in connection with high efficiency of mycotoxins’ removal was also considered. The main beer qualitative attributes such as pH value, color, iso-alpha acids were defined. As perspective adsorbents has shown to be carbon and modified silica gels. The retention of ochratoxin A on carbon was 90–96% in range of carbon dosages 2.5–6.5 g/l, and its retention on modified silica gels alters in scope of 64–94%. The retentive effect of fumonisin B1 and B2 on modified silica gels reached 74–100% in dependence on adsorbent dosage. Most changes underwent iso-alpha acids likely in consequence of retention on adsorbents together with mycotoxins. To achieve the scheduled goals the sensitive HPLC methods with fluorescence detection were used.     

Large‐Scale Study on Beer Filtration with Combined Filter Aid Additions to Cellulose Fibres

Kieselguhr or diatomaceous earth is the most commonly used filter aid for beer filtration. However, lately the use of kieselguhr has come under increased criticism. Some of the reasons for this are cost of disposal, limited resources and hazards to health from diatomite powder. One alternative to filtration with kieselguhr could be cellulose. Cellulose can be regenerated several times, is easy to dispose of, bears no health risks and as a renewable raw material is widely available. Previous single filtrations with cellulose were not satisfactory. A pre‐clarification of wort and green beer with silica sol was used in this work to improve the haze of the filtered beer. Furthermore, silica sol was added to the cellulose mixture for body‐feed during filtration. This represents a new field of application. When adding silica sol, filtrate haze was reduced in both applications. The intensity of this effect was dependent on how, when and where the material is added. Another future alternative could be rice hull ash because of its similarities to kieselguhr.     

Comparative study of soybean oil refining using rice hull silicate and commercial adsorbents

To obtain an edible grade of soybean oil, impurity removal processes are important steps in refining. To remove coloring compounds and free fatty acids, commercial adsorbents (silica gel, activated carbon, aluminum oxide, alumina silicate, acid clay, and zeolite) and rice hull silicate (RHS) were evaluated with respect to their adsorption removal efficiencies for lutein. Various doses of commercial adsorbents and RHS were individually added to degummed soybean oil to remove lutein. The commercial adsorbents and RHS substantially reduced lutein amounts in degummed soybean oil. Silica gel was the most effective adsorbent, followed by acid clay, and RHS. Treatments with adsorbents also reduced the residual free fatty acid (FFA) content. Aluminum oxide was the most effective in removal of FFA (approximately 40% reduction). RHS and rice hull ash (RHA) showed similar deacidification effects. RHS can be used as an alternative bleaching agent as it was effective in reducing the residual FFA content in soybean oil.     

Fungal mycoflora and mycotoxins in Korean polished rice destined for humans

Rice samples collected from the Republic of Korea were analyzed for fungal mycoflora and mycotoxins: fumonisins, ochratoxin A, trichothecenes, and zearalenone. The potential of the fungi to produce each mycotoxin was also examined, so that the fungal isolates associated with mycotoxins occurring in rice could be verified. Penicillium citrinum and Aspergillus candidus were the most prevalent species infecting the samples, while Fusarium proliferatum was found as the dominant Fusarium species. Ochratoxin A was the most commonly detected mycotoxin analyzed in the present study; moreover, its level in some samples was above the EU tolerable limit (3 ng/g). According to rice culture experiments, it was revealed that in Korea, fumonisins detected in rice were due to F. proliferatum infection, whereas the occurrence of ochratoxin A was caused by Penicillium verrucosum, though there were no symptoms of disease in rice found in any sample. Furthermore, there appears to be an uneven geographical distribution of P. verrucosum as well as ochratoxin A in that most of them are found in the rice samples produced in the northern region of Korea.     

Application of hybrid linear ion trap-high resolution mass spectrometry to the analysis of mycotoxins in beer

This paper reports the application of liquid chromatography electrospray ionization ion trap-orbitrap mass spectrometry for the determination of 18 mycotoxins (aflatoxins, fumonisins, trichothecenes, ochratoxin A, sterogmatocystin, beauvaricin, zearalenone and zearalenol) in beer. The extraction procedure was carried out by solid phase extraction (SPE): SPE columns were conditioned with acetonitrile/methanol and water. Beer was loaded onto the column which was washed with water. In these conditions, the recoveries were more than 65% and the relative standard deviation (RSD) were below 18%. The lowest limits of quantification (LLOQ) ranged from 9 to 155?ng?ml(-1). Matrix-matched calibration was performed for each beer and reliable results were obtained from selected mycotoxins. The method was applied to the analysis of 25 commercial beers. Taking advantage of the hybrid capabilities, the presence of other mycotoxins were checked; enniatins (A, A(1), B and B(1)) and fusaproliferin were studied in all the tested samples. The survey detected the presence of zearalenone in one stout beer sample.     

Co-occurrence of aflatoxin B1, fumonisin B1, ochratoxin A and zearalenone in cereals and peanuts from C?te d'Ivoire.

This survey examined 30 samples of rice (n = 10), maize (n = 10) and peanuts (n = 10) from C?te d'Ivoire for aflatoxin B1, fumonisin B1 and zearalenone using immunoassays, and ochratoxin A using a validated HPLC method with fluorescence detection. In C?te d'Ivoire, as in other countries, several mycotoxins are present in the same commodities. These mycotoxins are from different structural families: aflatoxin B1, fumonisin B1, zearalenone and ochratoxin A, normally produced by fungal species from Aspergillus, Penicillium and Fusarium genera. Some samples contained four mycotoxins (86%). Four peanuts samples did not show ochratoxin A (14%), whereas they contained aflatoxin B1 concentrations above the EU regulatory limits. Concentrations of ochratoxin A, zearalenone and fumonisin B1 were low and may not cause problems per se; however, fears remain that the tolerable daily intake may be exceeded due to eating habits and synergistic effects could be important with the combination of several mycotoxins. Investigations in this direction are underway, together with isolation and characterization of the fungal species involved.     

Natural occurrence of fumonisins and ochratoxin A in some herbs and spices commercialized in Poland analyzed by UPLC–MS/MS method

Unsanitary conditions during harvesting, drying, packing and storage stages in production and processing of spices and herbs could introduce mycotoxin contamination. The occurrence of ochratoxin A and fumonisins in popular spices and herbs was studied, using liquid chromatography-electrospray-mass spectrometry. Apart from mycotoxins, ergosterol as a factor indicating fungal development was also analysed. A total of 79 different samples commercialized in Poland were randomly purchased from popular markets were tested for mycotoxins. The frequency of samples with fumonisins was lower (31%) than ochratoxin A (49%). Free from mycotoxins were samples of bay leaf and white mustard. ERG content – in spice samples with high concentration level of mycotoxins – was also significantly higher than in samples with little to no mycotoxins.     

Ochratoxin A and Brewing Technology: A Review

Ochratoxins are a hazardous group of mycotoxins produced as secondary metabolites by several fungi of the Aspergillus and Penicillium families. Ochratoxins have been detected and determined in foods and beverages, including barley, malt and beer, at ppb levels. Varied analytical methods have been developed for the detection of ochratoxin A [OTA] in cereals and beer. Ochratoxin A has hazardous effects on health and has been classified within group 2B, as a possible human carcinogen by IARC. Scientists have expressed great concern about the presence of ochratoxin A in foods. In this article, chemical structure, biosynthesis by microorganisms, analytical methods for testing, regulations, changes during brewing, and detoxification of OTA, are reviewed. Beer poses very little risk as a source of ochratoxin in the diet.     

Mycotoxins in corn and wheat silage in Israel

Silage is an important feed source for intensive dairy herds worldwide. Fungal growth and mycotoxin production before and during silage storage is a well-known phenomenon, resulting in reduced nutritional value and a possible risk factor for animal health. With this in mind, a survey was conducted to determine for the first time the occurrence of mycotoxins in corn and wheat silage in Israel. A total of 30 corn and wheat silage samples were collected from many sources and analysed using a multi-mycotoxin method based on LC-MS/MS. Most mycotoxins recorded in the present study have not been reported before in Israel. Overall, 23 mycotoxins were found in corn silage; while wheat silage showed a similar pattern of mycotoxin occurrence comprising 20 mycotoxins. The most common post-harvest mycotoxins produced by the Penicillium roqueforti complex were not found in any tested samples, indicative of high-quality preparation and use of silage. Moreover, none of the European Union-regulated mycotoxins – aflatoxin B1, ochratoxin, T-2 toxin, diacetoxyscirpenol and deoxynivalenol – were found above their limits of detection (LODs). The Alternaria mycotoxins – macrosporin, tentoxin and alternariol methyl ether – were highly prevalent in both corn and wheat silage (>80%), but at low concentrations. The most prominent (>80%) Fusarium mycotoxins in corn silage were fusaric acid, fumonisins, beauvericin, monilifomin, equisetin, zearalenone and enniatins, whereas in wheat silage only beauvericin, zearalenone and enniatins occurred in more than 80% of the samples. The high prevalence and concentration of fusaric acid (mean = 765 µg kg^–1) in Israeli corn silage indicates that this may be the toxin of highest potential concern to dairy cow performance. However, more data from different harvest years and seasons are needed in order to establish a more precise evaluation of the mycotoxin burden in Israeli silage.     

A promising innovative technique for mycotoxin detoxification from beverages using biofilms of lactic acid bacteria

This study assessed the removal of aflatoxin M₁ (AFM₁) and ochratoxin A (OTA) from artificially contaminated whole UHT milk and red grape juice, respectively, using biofilms from Lactobacillus rhamnosus GG. Using ELISA, the level of AFM₁ and OTA removal from beverages was determined depending on various factors. Biofilms of various ages demonstrated varying degrees of AFM₁ removal capacity from phosphate-buffered saline (PBS). Different levels of AFM₁ contaminated whole UHT milk (0.1, 0.2, and 1 μg/L) and OTA contaminated red grape juice (2 and 4 μg/L) were tested in the detoxification process. The binding ability of mycotoxins was improved by increasing the biofilm surface area up to 70 cm². L. rhamnosus GG biofilm was effective in removing mycotoxins within a short contact time ranging from 1 to 10 min. The proportion of bound AFM₁ and OTA by L. rhamnosus GG biofilm was 64.6 and 98.3% respectively. A new machine has been proposed and used as a trial for detoxication purposes which would be a promising application in liquid food industries.     

Occurrence of aflatoxins, ochratoxin A, and fumonisins in retail foods in Japan

We conducted a survey of aflatoxin B1, B2, G1, and G2, ochratoxin A, and fumonisin B1, B2, and B3 contamination in various foods on the retail market in Japan in 2004 and 2005. The mycotoxins were analyzed by high-performance liquid chromatography, liquid chromatography-mass spectrometry, or high-performance thin-layer chromatography. Aflatoxins were detected in 10 of 21 peanut butter samples; the highest concentration of aflatoxin B1 was 2.59 microg/kg. Aflatoxin contamination was not found in corn products, corn, peanuts, buckwheat flour, dried buckwheat noodles, rice, or sesame oil. Ochratoxin A was detected in oatmeal, wheat flour, rye, buckwheat flour, green coffee beans, roasted coffee beans, raisins, beer, and wine but not in rice or corn products. Ochratoxin A concentrations in contaminated samples were below 0.8 microg/kg. Fumonisins were detected in popcorn, frozen corn, corn flakes, and corn grits. The highest concentrations of fumonisins B1, B2, and B3 in these samples were 354.0, 94.0, and 64.0 microg/kg, respectively.     

Migration of mycotoxins into rice starchy endosperm during the parboiling process

Considering the occurrence of rice contamination by mycotoxins and the increase in rice consumption, the present work had the objective of assessing the migration of mycotoxins into the starchy endosperm during the parboiling process, as to propose conditions that provide lower contamination levels. The newly harvested rice grain sample was examined for the natural occurrence of mycotoxins (aflatoxin B₁, aflatoxin B₂, deoxynivalenol, ochratoxin A, and zearalenone); only the presence of aflatoxin B₁ was found (17 ng/g). The samples were then artificially contaminated with deoxynivalenol and zearalenone, and the parboiling process was conducted according to a 2³ factorial planning with central point, having as variables the contamination level deoxynivalenol 720, 1440, and 2160 ng/g, and zearalenone 476, 952, and 1428 ng/g the soaking time (4, 5, and 6 h) and autoclave time (15, 22.5, and 30 min). Mycotoxins aflatoxin B₁ (AFA B₁), deoxynivalenol (DON), and zearalenone (ZEA) were confirmed and determined through gas chromatography. Findings showed a lower migration trend for AFA B₁ under 6 h of soaking and 30 min of autoclaving, for DON under 6 h of soaking regardless of the autoclaving time, and for ZEA under 4 h of soaking and 15 min of autoclaving. This information can contribute to the choice of process parameters that limit the migration of these mycotoxins if they happen in the raw material.     

Comparison of the adsorbent performance between rice hull ash and rice hull silica gel according to their structural differences

The microstructures of rice hull ash (RHA) and rice hull silica (RHS) were studied to understand its adsorption for free fatty acids (FFA) of degummed soybean oil. RHAs such as RHA300, RHA500, RHA700 and RHA900 were produced by heating rice hulls at temperatures of 300, 500, 700 and 900 °C, respectively. RHS500 was formed by alkali extraction of amorphous silica from RHA500. Heating temperature affects the pore development of RHAs, resulting in elongated large pores, as evident from the SEM data. A characteristic feature of amorphous material is shown in the XRD patterns of RHAs and RHS500 except RHA900. Although RHA500 has much lower surface area and pore volume compared to RHS500, it showed similar effectiveness in reducing FFA content of degummed soybean oil. It might be ascribed by higher macroporosity of RHA500 compared with RHS500, which was shown in the results of N₂ adsorption.     

Occurrence of aflatoxin B1, citrinin and ochratoxin A in rice in five provinces of the central region of Vietnam

The possible coexistence of three mycotoxins in rice, including aflatoxin B1 (AFB1), citrinin (CIT) and ochratoxin A (OTA), was investigated. The samples of rice were collected in large markets in five provinces of the central region of Vietnam. These toxins were extracted, purified and finally quantified by HPLC with fluorimetry detection. Contamination of AFB1 was found to be the most, followed by OTA, while contamination of CIT was insignificant. The coexistence of CIT with AFB1/OTA in rice was found in high percentage. Some samples overpassed the authorized limit by Europe in OTA and/or AFB1.     

Degradation of ochratoxin A by Aspergillus species

Mycotoxin contamination of agricultural products is a serious health hazard throughout the world. Besides attempts to eliminate mycotoxins from contaminated substrates by physical and chemical methods, the ability of microbes to degrade mycotoxins is now being widely examined. In this study, several Aspergillus species were examined for their ability to degrade ochratoxin A. A. fumigatus and black Aspergillus strains were found to detoxify ochratoxin A in culture media. The kinetics of ochratoxin A detoxification by an atoxigenic A. niger strain was examined by thin layer chromatography, high-performance liquid chromatography and an immunochemical technique. A. niger CBS 120.49 was found to effectively eliminate ochratoxin A from both liquid and solid media, and the degradation product, ochratoxin alpha, was also decomposed.     

Mycotoxin Contamination of Rice in China

Mycotoxin contamination in rice is generally lower than in other cereals such as corn or wheat. However, over 65% of the population in China consumes rice as a staple food. Due to the diversity of the climate across China, the southern region is characterized by high temperatures and humidities, especially in rainy season. Such conditions are optimal for the growth of fungi. The accumulative and transferrable characteristics of fungi mycotoxins pose a great potential threat as confirmed by high incidences of liver cancer in the Yangtze delta region. Major mycotoxins identified in China are aflatoxins and ochratoxin A, as well as fumonisins. The contents of aflatoxin B₁ (AFB₁) in rice are varied among different provinces and regions and generally less than 5 μg/kg. Although high incidences of positive aflatoxins samples have widely been detected, few samples were detected as exceeding the national's maximum residue limit (10 μg/kg). Limited information is available on risk assessment of human health hazards of mycotoxins in rice, children should be paid more attention to due to their having the highest mycotoxins exposure level, although the risks are generally at low levels from rice. Mycotoxins are mainly distributed in the outer layer of the paddy rice (also called rough rice, referring to whole rice grain with the hulls), and the AFB₁ content in bran is 8.4 times greater than that in brown rice (hulled rice). Further investigation should focus on isolation and identification of mycotoxins‐producing fungal strains, especially unknown mycotoxigenic fungal strains determination. Infection resistant rice breeding of mycotoxigenic fungal species may be a fundamental approach to guaranteeing rice safety in China.     

重庆地区辣椒、花椒、八角中真菌毒素污染状况分析

目的 了解重庆地区辣椒、花椒和八角中真菌毒素污染状况。方法 采用随机抽样方法,在重庆地区盘溪、菜园坝和江津三个市场,抽取180批次香辛料样品,采用HPLC-MS/MS检测黄曲霉毒素（AFB1、AFB2、AFG1和AFG2）、赭曲霉毒素A（OTA）和伏马毒素（FB1和FB2）。结果 重庆地区辣椒、花椒和八角中的真菌毒素总检出率分别为60.0%、100%、96.7%。AFs和OTA是三种香辛料最主要的污染毒素,其中AFG2是最主要的黄曲霉代谢产物。盘溪市场的AFs污染总体情况稍好,菜园坝市场AFs污染最严重;江津市场的OTA污染最为严重。结论 香辛料中存在真菌毒素污染,有必要建立香辛料中真菌毒素的限量标准。     

Simultaneous determination of 10 mycotoxins in grain by ultra-high-performance liquid chromatography–tandem mass spectrometry using 13C15-deoxynivalenol as internal standard

An ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for simultaneous determination of 10 mycotoxins in grain was developed. The selected mycotoxins were: deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, fusarenon X, moniliformin, zearalenone, zearalanone, ochratoxin A and ochratoxin B. The samples were extracted with aqueous acetonitrile (84?:?16,?v/v) and purified by reliable laboratory-made mixed cartridges. The analytes were separated on an Acquity UPLC HSS T3 column (100?×?2.1?mm,?1.8?µm) and eluted with a mobile phase of water containing 0.2% aqueous ammonia and acetonitrile/methanol (90?:?10,?v/v). All mycotoxins were detected with a Waters Micromass Quattro Ultima Pt tandem quadrupole mass spectrometer operating in negative electrospray ionization using multiple reaction monitoring mode. Accurate determination was achieved by employing commercial ¹³C₁₅-deoxynivalenol as internal standard, which compensated for target loss and eliminated matrix effects. The established method was further validated by determining the linearity (R ^2?>?0.9990), average recovery (75.8–106.5%), sensitivity (limit of quantitation 0.09–8.48?µg?kg^?1) and precision (relative standard deviation?≤?6.9%). It was shown to be a suitable method for simultaneous determination of 10 mycotoxins in grain. Finally, a total of 69 corn samples randomly collected from eastern and northern China were analyzed. The results showed that deoxynivalenol was the most frequently detected contaminant, whilst 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, zearalenone, zearalanone, fusarenon X and moniliformin also occurred frequently. Ochratoxin A and ochratoxin B were present only in trace amounts in a small number of samples.     

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