Importance of low substrate arsenic content in mushroom cultivation and safety of final food product

Arsenic Metabolism, Toxicity and Accumulation in the White Button Mushroom Agaricus bisporus

Mushrooms have unique properties in arsenic metabolism. In many commercial and wild-grown mushrooms, arsenobetaine (AsB), a non-toxic arsenical, was found as the dominant arsenic species. The AsB biosynthesis remains unknown, so we designed experiments to study conditions for AsB formation in the white button mushroom, Agaricus bisporus. The mushrooms were treated with various arsenic species including arsenite (As(III)), arsenate (As(V)), methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAsO), and their accumulation and metabolism were determined using inductively coupled mass spectrometer (ICP-MS) and high-pressure liquid chromatography coupled with ICP-MS (HPLC-ICP-MS), respectively. Our results showed that mycelia have a higher accumulation for inorganic arsenicals while fruiting bodies showed higher accumulation for methylated arsenic species. Two major arsenic metabolites were produced in fruiting bodies: DMAs(V) and AsB. Among tested arsenicals, only MAs(V) was methylated to DMAs(V). Surprisingly, AsB was only detected as the major arsenic product when TMAsO was supplied. Additionally, AsB was only detected in the fruiting body, but not mycelium, suggesting that methylated products were transported to the fruiting body for arsenobetaine formation. Overall, our results support that methylation and AsB formation are two connected pathways where trimethylated arsenic is the optimal precursor for AsB formation.

The importance of Cu × Pb interactions to Lentinula edodes yield, major/trace elements accumulation and antioxidants

Due to the use of various substrates in the production of edible mushrooms which may contain metals, including Cu and Pb, it is important to understand the influence of mutual interactions between them in the process of their accumulation in fruit bodies. For this reason, the effects of Cu, Pb, and Cu × Pb on yield, accumulation of five major elements (Ca, K, Mg, Na and P), trace elements (Cu, Pb and Fe) and some bioactive compounds in Lentinula edodes fruit bodies were studied. Both the metals were added in doses of 0.1 and 0.5 mM (Cu0.1, Cu0.5, Pb0.1, Pb0.5 and their combinations). The addition of the metals resulted in a reduction in size, amount and finally yield of fruit bodies. Depending on the presence of Cu and or Pb and their concentration in the substrate, both antagonism and synergism may occur. The influence on the accumulation of other determining elements was also recorded. Among phenolic compounds, phenolic acids and flavonoids were detected. 2,5-Dihydroxybenzoic acid dominated in fruit bodies in the control variant, Pb0.1, Pb0.5 and all experimental variants enriched with Cu + Pb, while gallic acid was the major phenolic after Cu0.1 and Cu0.5 addition. Only protocatechuic acid content increased in all combinations. A significant decrease of all aliphatic acid contents in comparison to the control variant was observed in the Cu0.1 and Pb0.1 variants. Significant stimulation of aliphatic acid synthesis was recorded in Cu0.5 and Pb0.5 variants and in the mixture of both the metals. The additions pointed to the possible role of the determined molecules in detoxification mechanisms.

Arsenic and Its Effect on Nutritional Properties of Oyster Mushrooms with Reference to Health Risk Assessment

Arsenic (As) contamination is endemic in West Bengal, India. Arsenic exposure through mushroom is lethal to health. Pleurotus sp. is globally consumed as food for its medicinal and nutritional values. This study was performed to evaluate the arsenic accumulation in mushroom through arsenic biomagnified rice straw substrate in relation to health risk assessment. Arsenic concentrations were higher in P. ostreatus (12.577 mg/kg DW) and Pleurotus sp. (12.446 mg/kg DW) cultivated in arsenic biomagnified rice straw as compared with P. ostreatus (0.472 mg/kg DW) and Pleurotus sp. (0.434 mg/kg DW) cultivated in non-contaminant rice straw; respectively. The bio-concentration factor (BCF) value of arsenic was highest in stem at 3rd flush for both P. ostreatus and Pleurotus sp. The health risk index (HRI) based on dietary intake of these arsenic biomagnified mushrooms was found moderately higher in both the species, so higher intake of these mushrooms will put people at health risk.

Toxicological risks and nutritional value of wild edible mushroom species -a half-century monitoring study

The content of major- and trace elements in wild-growing mushrooms has been subject to numerous studies, but the data on long-term trends in this regard are scarce. The aim of research was to determine the content of 34 elements in four edible mushroom species Boletus edulis, Imleria badia, Leccinum scabrum and Macrolepiota procera, and associated soil collected from Polish forests between 1974 and 2019. As initially hypothesized, the element concentration in the studied soil revealed an increasing trend and was positively correlated with their levels found in fruit bodies. Bioconcentrafion Factor values exceeding 1 were documented for all mushroom species for K, P, Ag, Cd, Cu, Hg, and Zn. When compared to the Adequate Intakes, all the mushroom species were found to be a good dietary source of K, P, and Zn (range of 6260-8690, 6260-8690 and 97-135 mg kg^-1 dry weight (dw), respectively), and B. edulis and I. badia a moderate source of Fe (mean 71.5 and 76.5 mg kg^-1 dw, respectively), B. edulis of Mn and Mo (mean 20.0 and 0.42 mg kg^-1 dw, respectively), while L. scabrum and M. procera a source of Cu. Consumption of the studied mushrooms would not lead to significant exposure to Al, As, Cr, or Ni. Considering that wild mushrooms will continue to be collected in Poland, one should bear in mind that they are a limited source of minerals in the human diet while their frequent, regular consumption, associated with exposure to selected toxic elements, should not be recommended.

Chronic dietary exposure to inorganic arsenic

Following an official request to EFSA from the European Commission, EFSA assessed the chronic dietary exposure to inorganic arsenic (iAs) in the European population. A total of 13,608 analytical results on iAs were considered in the current assessment (7,623 corresponding to drinking water and 5,985 to different types of food). Samples were collected across Europe between 2013 and 2018. The highest mean dietary exposure estimates at the lower bound (LB) were in toddlers (0.30 μg/kg body weight (bw) per day), and in both infants and toddlers (0.61 μg/kg bw per day) at the upper bound (UB). At the 95th percentile, the highest exposure estimates (LB-UB) were 0.58 and 1.20 μg/kg bw per day in toddlers and infants, respectively. In general, UB estimates were two to three times higher than LB estimates. The mean dietary exposure estimates (LB) were overall below the range of benchmark dose lower confidence limit (BMDL 01) values of 0.3-8 μg/kg bw per day established by the EFSA Panel on Contaminants in the Food Chain in 2009. However, for the 95th percentile dietary exposure (LB), the maximum estimates for infants, toddlers and other children were within this range of BMDL 01 values. Across the different age classes, the main contributors to the dietary exposure to iAs (LB) were 'Rice', 'Rice-based products', 'Grains and grain-based products (no rice)' and 'Drinking water'. Different ad hoc exposure scenarios (e.g. consumption of rice-based formulae) showed dietary exposure estimates in average and for high consumers close to or within the range of BMDL 01 values. The main uncertainties associated with the dietary exposure estimations refer to the impact of using the substitution method to treat the left-censored data (LB-UB differences), to the lack of information (consumption and occurrence) on some iAs-containing ingredients in specific food groups, and to the effect of food preparation on the iAs levels. Recommendations were addressed to improve future dietary exposure assessments to iAs.

Mineral composition of elements in wood-growing mushroom species collected from of two regions of Poland

The study monitored the content of 55 elements in 21 wood-growing mushroom species collected between 2013 and 2019 from Lower and Upper Silesia in Poland. Only 27 of the elements (Ag, Al, Ba, Ca, Cd, Cu, Fe, In, K, La, Mg, Mn, Na, Nd, Ni, P, Pb, Pr, Pt, Rh, Sr, Ti, Tm, V, Y, Zn, and Zr) were detected in all mushroom species, while others (As, Au, B, Be, Bi, Ce, Co, Cr, Dy, Er, Eu, Ga, Gd, Ge, Hf, Ho, Ir, Li, Lu, Mo, Os, Pb, Rb, Re, Ru, Sb, Sc, Se, Sm, Tb, Te, Th, Tl, Tm, U, and Yb) were below the limit of detection in the fruit bodies of at least one species. Wide ranges for major elements in the whole population of all the mushroom species were as follows: 15.4-470 (Ca), 6580-44,600 (K), 314-2150 (Mg), 38.0-319 (Na), and 1100-15,500 (P) mg kg^-1 dm, respectively. The rank sum revealed that M. giganteus fruit bodies were the most enriched with all detectable elements, while A. mellea had the lowest content of the majority of elements. Mushrooms belonging to the Hymenochaetaceae family were characterized as some of the most enriched with the studied elements, while mushrooms of the Fomitopsidaceae family had the lowest content of elements. Similarities as well as differences between the obtained results and the available literature data confirm the important role of both mushroom species and the tree on which the fungus has grown.

Arsenic speciation in the bracket fungus Fomitopsis betulina from contaminated and pristine sites

Uptake, distribution and speciation of arsenic (As) were determined in the bracket fungus Fomitopsis betulina (previously Piptoporus betulinus), commonly known as the birch polypore, collected from a woodland adjacent to a highly contaminated former mine in the Southwest UK and at an uncontaminated site in Quebec, Canada, with no past or present mining activity. The fruiting body was divided into cap, centre and pores representing the top, middle and underside to identify trends in the distribution and transformation of As. Total As, determined by inductively coupled plasma-mass spectrometry (ICP-MS), was approximately tenfold higher in the mushroom from the contaminated compared to the uncontaminated site. Overall, accumulation of As was low relative to values reported for some soil-dwelling species, with maximum levels of 1.6 mg/kg at the contaminated site. Arsenic speciation was performed on aqueous extracts via both anion and cation high-performance liquid chromatography-ICP-MS (HPLC-ICP-MS) and on whole dried samples using X-ray absorption near edge structure (XANES) analysis. Seven As species were detected in F. betulina from the contaminated site by HPLC-ICP-MS: arsenite (As^III), arsenate (As^V), dimethylarsinate (DMA^V), methylarsonate (MA^V), trimethylarsine oxide (TMAO), tetramethylarsonium ion (Tetra) and trace levels of arsenobetaine (AB). The same As species were observed at the uncontaminated site with the exception of TMAO and Tetra. Arsenic species were localized throughout the fruiting body at the contaminated site, with the cap and pores containing a majority of As^V, only the cap containing TMAO, and the pores containing higher concentrations of DMA^V and MA^V as well as tetra and a trace of AB. XANES analysis demonstrated that the predominant form of As at the contaminated site was inorganic As^III coordinated with sulphur or oxygen and As^V coordinated with oxygen. This is the first account of arsenic speciation in F. betulina or any fungi of the family Fomitopsidaceae.

Arsenic and arsenic speciation in mushrooms from China: A review

Arsenic (As) is a natural environmental contaminant to which humans are usually exposed in water, air, soil, and food. China is a typical high-As region, and also a great contributor of the world production of cultivated edible mushrooms and a region abundant in wild growing edible mushrooms. Mushrooms can accumulate different amounts of As and different As compounds, so potential health risk of As intake may exist to people who use mushrooms with elevated As contents as food or medicine. A systematic literature search was carried out for studies on As and As compounds in mushrooms from China. We compiled existing data from published sources in English or Chinese and provide an updated review of the findings on As in mushrooms associated with environments and health risks. Future perspectives for studies on As in mushrooms have also been discussed.

Contents and Health Risk Assessment of Elements in Three Edible Ectomycorrhizal Fungi (Boletaceae) from Polymetallic Soils in Yunnan Province, SW China

Ectomycorrhizal fungi (EcMF) can mobilize mineral elements directly from insoluble mineral sources and accumulate various metallic elements and metalloids from soils to their fruiting bodies. Mushrooms from genus Boletus and its related genus are one of the most important EcMF which are consumed worldwide as wild edible mushrooms. Yunnan province (China) is a high biodiversity of genus Boletus mushrooms but is also an area with potential elevated contents of toxic elements in soil. Total contents of As, Ag, Ba, Cd, Co, Cr, Cs, Cu, Li, Mn, Ni, Pb, Rb, Sb, Sr, Tl, U, V, and Zn in three edible EcMF species collected from five sites of Yunnan were analyzed by inductively coupled plasma mass spectrometer. The highest contents for As, Cd, and Pb were 7.8 mg kg^-1 dry weight (dw) in the caps of Butyriboletus roseoflavus, 3.4 mg kg^-1 dw in the caps of B. roseoflavus, and 6.4 mg kg^-1 dw in the stipes of Hemileccinum impolitum. Health risk assessment of As, Cd, and Pb indicated that the estimated exposure due to intakes of some mushroom samples from the sites were above the limits recommended by the Joint FAO/WHO Expert Committee on Food Additives. Since EcMF were considered as bioexclusors of Cr, higher Cr contents in the mushroom samples, compared with previous studies, indicated high geochemical background value of Cr in the sampling sites. Relatively higher V contents in mushrooms from family Boletaceae could also associate with the high V contents in Yunnan soil. Further work is needed to identify the places in Yunnan with geochemical anomalies resulting in high levels of toxic elements in EcMF.

Worldwide basket survey of multielemental composition of white button mushroom Agaricus bisporus

Agaricus bisporus is the most commonly cultivated and consumed mushroom species. The aim of this study was to compare the profile of macro- and trace elements in A. bisporus fruit bodies produced commercially in 19 countries in 2018 and distributed worldwide (32 analyzed objects). Trace elements with unknown biological roles were also determined. The content of 36 elements (of 70 taken into account) revealed significant differences among the analyzed objects. Contents of Ca, K, Mg, Na and S varied in wide ranges of 425-2430, 12740-40940, 610-3240, 98-430 and 1030-2650 mg kg^-1 dw, respectively. The fruit bodies were characterized by a generally similar content of trace elements with some clear exceptions. Rankings of the objects according to the decreased amount of macroelements, trace elements and all elements jointly, show that mushrooms are significantly diverse as regards the content of particular elements of the mentioned group. The analyzed fruit bodies displayed a relatively high content of Ca, Mo and Se, and a high K/Na ratio. Regardless of origin, A. bisporus did not constitute a source of significant levels of Al, Cd or rare earth elements. An increased level of As and Pb in mushrooms from several producers indicates a need for additional measures to reduce potential dietary exposures to these toxicants.

Mycoprotein: environmental impact and health aspects

The term mycoprotein refers to the protein-rich food made of filamentous fungal biomass that can be consumed as an alternative to meat. In this paper, the impact caused by the substitution of animal-origin meat in the human diet for mycoprotein on the health and the environment is reviewed. Presently, mycoprotein can be found in the supermarkets of developed countries in several forms (e.g. sausages and patties). Expansion to other markets depends on the reduction of the costs. Although scarce, the results of life cycle analyses of mycoprotein agree that this meat substitute causes an environmental impact similar to chicken and pork. In this context, the use of inexpensive agro-industrial residues as substrate for mycoprotein production has been investigated. This strategy is believed to reduce the costs involved in the fungal cultivation and lower the environmental impact of both the mycoprotein and the food industry. Moreover, several positive effects in health have been associated with the substitution of meat for mycoprotein, including improvements in blood cholesterol concentration and glycemic response. Mycoprotein has found a place in the market, but questions regarding the consumer's experience on the sensory and health aspects are still being investigated.

Arsenic and Other Elemental Concentrations in Mushrooms from Bangladesh: Health Risks

Mushroom cultivation has been increasing rapidly in Bangladesh. Arsenic (As) toxicity is widespread in the world and Bangladesh faces the greatest havoc due to this calamity. Rice is the staple food in Bangladesh and among all the crops grown, it is considered to be the main cause of As poisoning to its population after drinking water. Consequently, rice straw, an important growing medium of mushrooms in Bangladesh, is known to have high As content. The objective of this study was, therefore, to determine the concentrations of As in mushrooms cultivated in Bangladesh and to assess the health risk as well. It also considered other elements, including Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn concentrations in mushrooms from Bangladesh. The mean concentrations (mg/kg) of As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn in mushrooms were 0.51, 0.38, 0.28, 0.01, 13.7, 0.31, 11.7, 0.12, 0.28, and 53.5, respectively. Based on the dietary intake of mushrooms, the weekly intakes of As, Cd, Cr, Co, Cu, Pb, Mn, Hg, Ni, and Zn from mushrooms for adults were 0.0042, 0.0030, 0.0024, 0.0001, 0.1125, 0.0019, 0.1116, 0.0011, 0.0023, and 0.4734 mg, respectively. Due to the low concentrations of As and other trace elements observed in mushrooms from Bangladesh, as well as relatively lower consumption of this food in people’s diet, it can be inferred that consumption of the species of mushrooms analysed will cause no toxicological risk.

Multi-elemental analysis of Lentinula edodes mushrooms available in trade

The present study investigated the content of 62 elements in the fruiting bodies of Lentinula edodes (Shiitake mushroom) cultivated commercially in Poland on various substrates from 2007-2015. The general mean content (mg kg^-1 dry weight (DW)) of the studied elements ranked in the following order: K (26,335) > P (11,015) > Mg (2,284) > Ca (607) > Na (131) > Zn (112) > Fe (69) > Mn (33) > B (32) > Rb (17) > Cu (14.5) > Al (11.2) > Te (2.9) > As (1.80) > Cd (1.76) > Ag (1.73) > Nd (1.70) > Sr (1.46) > Se (1.41) > U (1.11) > Pt (0.90) > Ce (0.80) > Ba (0.61) > Co (0.59) > Tl (0.58) > Er (0.50) > Pb (0.42) > Li (0.40) > Pr (0.39) > Ir (0.37) > In (0.35) > Mo (0.31) > Cr (0.29) > Ni (0.28) > Sb (0.26) > Re (0.24) > Ti (0.19) > Bi (0.18) > Th (0.12) > La (0.10) = Pd (0.10) > Os (0.09) = Zr (0.09) > Rh (0.08) > Ho (0.07) > Ru (0.06) > Sm (0.04) = Eu (0.04) = Tm (0.04) > Gd (0.03) > Sc (0.02) = Y (0.02) > Lu (0.01) = Yb (0.01) = V (0.01). The contents of Au, Be, Dy, Ga, Ge, Hf, and Tb were below the limits of detection (0.02, 0.02, 0.01, 0.01, 0.01, 0.01, 0.02 mg kg^-1 respectively). The concentrations of Al, As, B, Ba, Ca, Cd, Cr, Er, Fe, In, Lu, Mn, Nd, Sr, Ti, Tm, and Zr were comparable over the period the mushrooms were cultivated. The study revealed that Lentinula edodes contained As and Cd at levels potentially adverse to human health. This highlights the need to monitor these elements in food products obtained from this mushroom species and ensure that only low levels of these elements are present in cultivation substrates.

Contamination level, distribution and health risk assessment of heavy and toxic metallic and metalloid elements in a cultivated mushroom Pleurotus florida (Mont.) singer

There are great concentrations of toxic metallic and metalloid elements such as lead, arsenic, mercury, cadmium or silver in many species of mushrooms comparative to other fruits and vegetables. In this study, contamination with heavy and toxic metallic and metalloid elements in the cultivated mushroom of (Pleurotus florida (Mont.) Singer) is investigated. P. florida was cultivated on different substrates; wheat straw (as blank), wheat straw + pine cone, wheat straw + soybean straw and wheat straw + urea and the effects of these substrates on contamination levels of Mn, Fe, Cu, Zn, As, Cd, and Pb were analyzed. The results showed that the concentrations of essential elements (Mn, Fe, Cu, and Zn) in the target mushroom are at the typical levels. The estimated daily intakes of studied metallic and metalloid elements were below their oral reference dosage mentioned by the international regulatory bodies. Health risk index (HRI) was calculated to evaluate the consumer's health risk assessment from the metal intake that contaminated in the cultivated mushroom of P. florida on the different nutrient sources. In this study, the individual HRIs were less than 1, which indicates insignificant potential health risk associated with the consumption of target mushroom from the studied substrates. Based on the HRIs values among the toxic metallic and metalloid elements, As in the target mushroom in the substrate of the wheat straw + pine cone is the main sources of risk, and it may cause severe health problems. Thus, this study suggests that the concentrations of heavy and toxic elements should be periodically monitored in cultivated mushrooms.

Inorganic Arsenic Determination in Food: A Review of Analytical Proposals and Quality Assessment Over the Last Six Years

Here we review recent developments in analytical proposals for the assessment of inorganic arsenic (iAs) content in food products. Interest in the determination of iAs in products for human consumption such as food commodities, wine, and seaweed among others is fueled by the wide recognition of its toxic effects on humans, even at low concentrations. Currently, the need for robust and reliable analytical methods is recognized by various international safety and health agencies, and by organizations in charge of establishing acceptable tolerance levels of iAs in food. This review summarizes the state of the art of analytical methods while highlighting tools for the assessment of quality assessment of the results, such as the production and evaluation of certified reference materials (CRMs) and the availability of specific proficiency testing (PT) programmes. Because the number of studies dedicated to the subject of this review has increased considerably over recent years, the sources consulted and cited here are limited to those from 2010 to the end of 2015.

Study of silver, selenium and arsenic concentration in wild edible mushroom Macrolepiota procera, health benefit and risk

The content and bioaccumulation of trace (Ag, Se, As) and major elements (Ca, Mg, Na and K) in wild edible mushroom Macrolepiota procera and its corresponding soil substrates, collected from five sites in the Rasina region in central Serbia, were investigated. The content of Ag, As and Se was determined by inductively coupled plasma mass spectrometer (ICP-MS) while the amount of Ca, Mg, Na and K was determined by inductively coupled plasma optical emission spectrometer (ICP-OES). The concentrations of major elements in the mushrooms were at typical levels. As far as trace elements are concerned, M. procera bioaccumulates silver although all samples were collected from unpolluted sites. It was found that the content of Ag depended on the geographical origin and the density of fruiting body on the certain site. Principal component analysis distinguished the mushroom samples from different geographical areas and revealed the influence of soil composition on metal content in fruiting bodies. Also, a linear regression correlation test was performed to investigate correlations between Ag, Cd, Se, Pb and As in caps and stipes at different geographic sites separately. In addition, our results indicated that M. procera could serve as a good dietary source of Mg, K and Se. The content of Ag and As was low, so it could not pose a health risk for consumers.

Arsenic and its compounds in mushrooms: A review

The purpose of this article is to review the detail concentration of arsenic in some species of mushrooms as well as organic and inorganic forms of arsenic in the substrates where wild and cultivated edible mushrooms grow. We also briefly review the molecular forms of arsenic in mushrooms. There is still a lack of experimental data from the environment for a variety of species from different habitats and for different levels of geogenic arsenic in soil. This information will be useful for mushrooms consumers, nutritionists, and food regulatory agencies by describing ways to minimize arsenic content in edible mushrooms and arsenic intake from mushroom meals.