Ochratoxins in feed, a risk for animal and human health: control strategies

An accurate and ultrasensitive ratiometric electrochemical aptasensor for determination of Ochratoxin A based on catalytic hairpin assembly

Ochratoxin A (OTA) pollution in agricultural products has raised the pressing to develop sensitive, accurate and convenient detection methods. Herein, an accurate and ultrasensitive ratiometric electrochemical aptasensor was proposed based on catalytic hairpin assembly (CHA) for OTA detection. In this strategy, the target recognition and CHA reaction were both accomplished in the same system, which avoided tedious multi-steps operation and extra reagents, providing the advantage of convenience with only a one-step reaction and without enzyme. The labeled Fc and MB were used as the signal-switching molecules, avoiding various interferences and greatly improving the reproducibility (RSD: 3.197%). This aptasensor achieved trace-level detection for OTA with LOD of 81 fg/mL in the linear range of lower concentration (100 fg/mL-50 ng/mL). Moreover, this strategy was successfully applied to OTA detection in cereals with comparable results of HPLC-MS. This aptasensor provided a viable platform for accurate, ultrasensitive, and one-step detection of OTA in food.

Mycotoxin Contamination Status of Cereals in China and Potential Microbial Decontamination Methods

The presence of mycotoxins in cereals can pose a significant health risk to animals and humans. China is one of the countries that is facing cereal contamination by mycotoxins. Treating mycotoxin-contaminated cereals with established physical and chemical methods can lead to negative effects, such as the loss of nutrients, chemical residues, and high energy consumption. Therefore, microbial detoxification techniques are being considered for reducing and treating mycotoxins in cereals. This paper reviews the contamination of aflatoxins, zearalenone, deoxynivalenol, fumonisins, and ochratoxin A in major cereals (rice, wheat, and maize). Our discussion is based on 8700 samples from 30 provincial areas in China between 2005 and 2021. Previous research suggests that the temperature and humidity in the highly contaminated Chinese cereal-growing regions match the growth conditions of potential antagonists. Therefore, this review takes biological detoxification as the starting point and summarizes the methods of microbial detoxification, microbial active substance detoxification, and other microbial inhibition methods for treating contaminated cereals. Furthermore, their respective mechanisms are systematically analyzed, and a series of strategies for combining the above methods with the treatment of contaminated cereals in China are proposed. It is hoped that this review will provide a reference for subsequent solutions to cereal contamination problems and for the development of safer and more efficient methods of biological detoxification.

Protective effect of selenomethionine on kidney injury induced by ochratoxin A in rabbits

The purpose of this study was to investigate the protective effect and mechanism of selenomethionine (SeMet) on ochratoxin A (OTA)-induced nephrotoxicity in rabbits. In total, sixty Ira rabbits were randomly divided into 5 groups (the control group, OTA group, 0. 2 mg/kg SeMet + OTA group, 0. 4 mg/kg SeMet + OTA group, and 0. 6 mg/kg SeMet + OTA group). The rabbits were fed diets supplemented with different doses of SeMet for 21 days and given 0. 2 mg/kg OTA starting on day 15 for a week. The results showed that the SeMet supplementation could improve the changes in blood physiological indices and renal function decline caused by OTA poisoning, and alleviate pathological kidney injury in the rabbits. SeMet also increased the activities of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase, and decreased the contents of malondialdehyde and reactive oxygen species and the expression of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the damaged kidneys of the rabbits. In addition, the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream gene heme oxygenase 1 (HO-1) was also inhibited after OTA poisoning, while SeMet activated the Nrf2 signaling pathway and enhanced the expression of Nrf2 and the downstream gene HO-1. In conclusion, SeMet protected against kidney injury caused by OTA in rabbits, and the mechanism may be the activation of the Nrf2 signaling pathway.

A Newly Isolated Alcaligenes faecalis ANSA176 with the Capability of Alleviating Immune Injury and Inflammation through Efficiently Degrading Ochratoxin A

Ochratoxin A (OTA) is one of the most prevalent mycotoxins that threatens food and feed safety. Biodegradation of OTA has gained much attention. In this study, an Alcaligenes faecalis strain named ANSA176, with a strong OTA-detoxifying ability, was isolated from donkey intestinal chyme and characterized. The strain ANSA176 could degrade 97.43% of 1 mg/mL OTA into OTα within 12 h, at 37 °C. The optimal levels for bacterial growth were 22–37 °C and pH 6.0–9.0. The effects of ANSA176 on laying hens with an OTA-contaminated diet were further investigated. A total of 36 laying hens were assigned to three dietary treatments: control group, OTA (250 µg/kg) group, and OTA + ANSA176 (6.2 × 10⁸ CFU/kg diet) group. The results showed that OTA decreased the average daily feed intake (ADFI) and egg weight (EW); meanwhile, it increased serum alanine aminopeptidase (AAP), leucine aminopeptidase (LAP), β2-microglobulin (β2-MG), immunoglobulin G (IgG), tumor necrosis factor-α (TNF-α), and glutathione reductase (GR). However, the ANSA176 supplementation inhibited or attenuated the OTA-induced damages. Taken together, OTA-degrading strain A. faecalis ANSA176 was able to alleviate the immune injury and inflammation induced by OTA.

Toolbox for the Extraction and Quantification of Ochratoxin A and Ochratoxin Alpha Applicable for Different Pig and Poultry Matrices

Ochratoxin A (OTA) is one of the major mycotoxins causing severe effects on the health of humans and animals. Ochratoxin alpha (OTα) is a metabolite of OTA, which is produced through microbial or enzymatic hydrolysis, and one of the preferred routes of OTA detoxification. The methods described here are applicable for the extraction and quantification of OTA and OTα in several pig and poultry matrices such as feed, feces/excreta, urine, plasma, dried blood spots, and tissue samples such as liver, kidney, muscle, skin, and fat. The samples are homogenized and extracted. Extraction is either based on a stepwise extraction using ethyl acetate/sodium hydrogencarbonate/ethyl acetate or an acetonitrile/water mixture. Quantitative analysis is based on reversed-phase liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Method validation was successfully performed and the linearity, limit of quantification, accuracy, precision as well as the stability of the samples, were evaluated. The analyte recovery of the spiked samples was between 80 and 120% (80–150% for spiked concentrations ≤ 1 ng/g or ng/mL) and the relative standard deviation was ≤ 15%. Therefore, we provide a toolbox for the extraction and quantification of OTA and OTα in all relevant pig and poultry matrices.

Ochratoxin A and Kidney Oxidative Stress: The Role of Nutraceuticals in Veterinary Medicine-A Review

The problem of residues of toxic contaminants in food products has assumed considerable importance in terms of food safety. Naturally occurring contaminants, such as mycotoxins, are monitored routinely in the agricultural and food industries. Unfortunately, the consequences of the presence of mycotoxins in foodstuffs are evident in livestock farms, where both subacute and chronic effects on animal health are observed and could have non-negligible effects on human health. Ochratoxin A (OTA) is a common mycotoxin that contaminates food and feeds. Due to its thermal stability, the eradication of OTA from the food chain is very difficult. Consequently, humans and animals are frequently exposed to OTA in daily life. In this review article, we will devote time to highlighting the redox-based nephrotoxicity that occurs during OTA intoxication. In the past few decades, the literature has improved on the main molecules and enzymes involved in the redox signaling pathway as well as on some new antioxidant compounds as therapeutic strategies to counteract oxidative stress. The knowledge shown in this work will address the use of nutraceutical substances as dietary supplements, which would in turn improve the prophylactic and pharmacological treatment of redox-associated kidney diseases during OTA exposure, and will attempt to promote animal feed supplementation.

Ochratoxin A as alarming health in livestock and human: A review on molecular interactions, mechanism of toxicity, detection, detoxification, and dietary prophylaxis

Ochratoxin A (OTA) is a toxic metabolite produced by Aspergillus and Penicillium fungi commonly found in raw plant sources and other feeds. This review comprises an extensive evaluation of the origin and proprieties of OTA, toxicokinetics, biotransformation, and toxicodynamics of ochratoxins. In in vitro and in vivo studies, the compatibility of OTA with oxidative stress is observed through the production of free radicals, resulting in genotoxicity and carcinogenicity. The OTA leads to nephrotoxicity as the chief target organ is the kidney. Other OTA excretion and absorption rates are observed, and the routes of elimination include faeces, urine, and breast milk. The alternations in the Phe moiety of OTA are the precursor for the amino acid alternation, bringing about Phe-hydroxylase and Phe-tRNA synthase, resulting in the complete dysfunction of cellular metabolism. Biodetoxification using specific microorganisms decreased the DNA damage, lipid peroxidation, and cytotoxicity. This review addressed the ability of antioxidants and the dietary components as prophylactic measures to encounter toxicity and demonstrated their capability to counteract the chronic exposure through supplementation as feed additives.

An integrated systems-level model of ochratoxin A toxicity in the zebrafish (Danio rerio) embryo based on NMR metabolic profiling

Ochratoxin A (OTA) is one of the most widespread mycotoxin contaminants of agricultural crops. Despite being associated with a range of adverse health effects, a comprehensive systems-level mechanistic understanding of the toxicity of OTA remains elusive. In the present study, metabolic profiling by high-resolution magic angle spinning (HRMAS) NMR, coupled to intact zebrafish embryos, was employed to identify metabolic pathways in relation to a systems-level model of OTA toxicity. Embryotoxicity was observed at sub-micromolar exposure concentrations of OTA. Localization of OTA, based on intrinsic fluorescence, as well as a co-localization of increased reactive oxygen species production, was observed in the liver kidney, brain and intestine of embryos. Moreover, HRMAS NMR showed significant alteration of metabolites related to targeting of the liver (i.e., hepatotoxicity), and pathways associated with detoxification and oxidative stress, and mitochondrial energy metabolism. Based on metabolic profiles, and complementary assays, an integrated model of OTA toxicity is, thus, proposed. Our model suggests that OTA hepatotoxicity compromises detoxification and antioxidant pathways, leading to mitochondrial membrane dysfunction manifested by crosstalk between pathways of energy metabolism. Interestingly, our data additionally aligns with a possible role of mitochondrial fusion as a "passive mechanism" to rescue mitochondrial integrity during OTA toxicity.

Mycobiota profile, phenology, and potential toxicogenic and pathogenic species associated with stored groundnuts (Arachis hypogaea L.) from the Volta Region, Ghana

This study updates the mycobiota resident in groundnut seeds, their phenology during storage with the view to ascertain their occurrence, potential toxigenic species, and pathologically important species in the stored samples. The moisture content of the seeds ranged from 5.7% to 6.5% within the stipulated safe moisture content of 8% for extension of shelf life. Culturing the seeds on mycological media (Sabouraud's Dextrose Agar SDA; Oxytetracycline Glucose Yeast Extract OGYE, Potato Dextrose Agar, PDA) caused a de novo growth of the quiescent spores at 28-30°C for 7-14 days. Fungal population counts on the three media ranged from 2.01 to 2.16 log₁₀ CFU/g samples to a final 6-month count of 1.67-2.60 log₁₀ CFU/g. Eighteen different fungal species belonging to ten genera were encountered on the media, namely Aspergillus, Cladosporium, Curvularia, Fusarium, Penicillium, Trichoderma, Rhizopus, Rhodotorula, Sporendonema, and Paecilomyces. Aspergillus spp. (A. niger, A. flavus, A. fumigatus, and A. terreus) were the most frequently isolated, followed by Fusarium species (F. oxysporum, F. solani, and F. verticillioides), Trichoderma (T. harzianum and T. viride), Rhizopus spp (R. oligosporus and R. stolonifer), and Penicillium verrucosum. The species which were seed borne (A. niger, A. flavus, A. terreus, A. fumigatus, F. solani, F. verticillioides, T. viride, C. herbarum, and Curvularia lunata) were isolated on both surface sterilized and non-surface sterilized seeds. The phenology of the encountered fungal species generally followed five patterns. The most frequently isolated Aspergillus niger, A. flavus, and A. fumigatus predominated throughout the 6 months sampling period, while A. ustus and A. terreus appeared sporadically and disappeared. The early colonizers (R. oligosporus, R. stolonifer, and Paecilomyces) could not be isolated after 2-3 months owing presumably to stronger antibiosis competition from the Aspergillus species. The most predominant Aspergillus species initially constituted 36%-48% of the total population but declined to 10%-36% in 6 months. Mycobiota encountered with mycotoxigenic potential and human health importance were A. niger, A. flavus, A. fumigatus, F. verticillioides, and Penicillium verrucosum. Other species of pathological importance to plants were Curvularia lunata and Fusarium oxysporum. The practical implications of these findings are discussed.

Dietary Trichosporon mycotoxinivoron modulates ochratoxin-A induced altered performance, hepatic and renal antioxidant capacity and tissue injury in broiler chickens

Ochratoxin A (OTA), an important fungal metabolite in foods and feeds has been shown to induce oxidative stress and cellular injuries to human and animal subjects. This study was designed to investigate the mode of action of a biological modifier Trichosporon mycotoxinivorans (TM), against OTA-mediated oxidative stress and tissue toxicity on broiler chickens. The birds were offered diets supplemented with OTA (0.15 and 0.3 mg/kg feed) and/or TM (0.5, 1.0 g/kg) for 42 days of age, and blood and tissue samples were collected to examine the oxidative stress, biochemical and histopathological parameters. Dietary OTA at all the tested levels induced the hepatic and renal tissue injury as indicated by significant decreased total antioxidant capacity in these organs along with significant decreased (p ≤ 0.05) serum concentrations of total proteins and albumin. The serum concentrations of alanine aminotransferase (ALT) and urea were significantly increased, and these observations were further supported by degenerative changes and increased relative weights of liver and kidneys. The dietary supplementation of TM at both tested levels relieved the detrimental impact of 0.15 and 0.3 mg OTA/kg on the studied parameters. The results of the study demonstrated that dietary TM significantly protects broiler chickens by reducing OTA-induced oxidative damage and tissue injury.

Occurrence of Ochratoxin A in Different Types of Cheese Offered for Sale in Italy

The detection of Ochratoxin A (OTA) in the milk of ruminants occurs infrequently and at low levels, but its occurrence may be higher in dairy products such as cheese. The aim of this study was to investigate the presence of OTA in cheeses purchased in the metropolitan city of Bologna (Italy) and the surrounding area. For the analysis, a LC-MS/MS method with a limit of quantification (LOQ) of 1 µg/kg was used. OTA was detected in seven out of 51 samples of grated hard cheese (concentration range 1.3-22.4 µg/kg), while it was not found in the 33 cheeses of other types which were also analysed. These data show a low risk of OTA contamination for almost all types of cheese analysed. To improve the safety of cheese marketed in grated form, more regulations on cheese rind, which is the part most susceptible to OTA-producing moulds, should be implemented or, alternatively, producers should consider not using the rind as row material for grated cheese. It would be interesting to continue these investigations particularly on grated hard cheeses to have more data to update the risk assessment of OTA in cheese, as also suggested by EFSA in its 2020 scientific opinion on OTA.

Investigation of a Novel Multicomponent Mycotoxin Detoxifying Agent in Amelioration of Mycotoxicosis Induced by Aflatoxin-B1 and Ochratoxin A in Broiler Chicks

The present study was designed to determine the efficacy of a novel multicomponent mycotoxin detoxifying agent (MMDA) containing modified zeolite (Clinoptilolite), Bacillus subtilis, B. licheniformis, Saccharomyces cerevisiae cell walls and silymarin against the deleterious effects of Aflatoxin B₁ (AFB₁) and Ochratoxin A (OTA) in broiler chicks. A total of 160 one-day-old Ross 308^® broiler chicks were randomly allocated in four treatment groups, with four replicates, according to the following experimental design for 42 days. Group A received a basal diet; Group B received a basal diet contaminated with AFB₁ and OTA at 0.1 mg/kg and 1 mg/kg, respectively; Group C received a basal diet contaminated with AFB₁ and OTA and MMDA at 1 g/kg feed, and Group D received a basal diet contaminated with AFB₁ and OTA and MMDA at 3 g/kg feed. Results showed that ingested mycotoxins led to significant (p ≤ 0.05) reduction in body weight and feed conversion from 25 days of age, induced histopathological changes, increased the pH of the intestinal content, and altered the biochemical profile of birds with significantly (p ≤ 0.05) increased aspartate aminotransferase (AST) values (p ≤ 0.05). On the other hand, the supplementation of MMDA significantly (p ≤ 0.05) improved the feed conversion ratio (FCR) during the second part of the study, diminished biochemical alterations, reduced pH in jejunal and ileal content, and E. coli counts in the caeca of birds (p ≤ 0.05). It may be concluded that the dietary supplementation of the MMDA partially ameliorated the adverse effects of AFB₁ and OTA in broilers and could be an efficient tool in a mycotoxin control program.

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.

Ochratoxin A: Carryover from animal feed into livestock and the mitigation strategies

This review aims to highlight the effects of ochratoxin A (OTA) in the feed of meat-producing animals. The accumulation of OTA in feed and its distribution in various farm animals were compared and evaluated. Primarily, the oral administration of OTA-contaminated feed and the predisposition in an animal's vital organ were critically examined in this work. The collated reports show that OTA directly associated with endemic nephropathy and its high concentration leads to degeneration of liver cells, and necrosis of intestinal and lymphoid tissues. At present, limited reports are available in the recent literature on the problems and consequences of OTA in feed. Therefore, this review focused on the OTA carryover from feed to farm animals and the interaction of its secondary metabolites on their biochemical parameters. Hence, this report provides greater insights into animal health related to OTA residues in meat and meat products. This article also explores mitigation strategies that can be used to prevent the carryover effects of OTA in livestock feeds and the effects in the food chain.

Evaluation of berberine efficacy in reducing the effects of aflatoxin B1 and ochratoxin A added to male broiler rations

Many types of mycotoxins are found in food sources contaminated with fungi, and if these are ingested in large quantities or over a long period, they can affect the health of humans and domestic animals. Berberine (BBR) is a plant alkaloid with multiple pharmacological functions. This study aimed to investigate the effect of different levels of the plant alkaloid BBR on reducing toxic effects of aflatoxin B1 (AFB) and ochratoxin A (OTA) in broilers by examining performance characteristics, blood biochemistry, antioxidant systems, ileum morphology, and histopathology of the liver. The experiment was performed with 288 Ross 308 broilers reared in floor pens for 42 d in a randomized design with 9 treatments. Each treatment was replicated 4 times, and each replicate contained 8 chicks. Experimental treatments included (1) negative control diet with no additives (NC); (2) NC + 2 ppm AFB (positive control AFB; PCAFB); (3) NC + 2 ppm OTA (positive control OTA; PCOTA); (4) PCAFB + 200 mg/kg BBR; (5) PCAFB + 400 mg/kg BBR; (6) PCAFB + 600 mg/kg BBR; (7) PCOTA + 200 mg/kg BBR; (8) PCOTA + 400 mg/kg BBR; and (9) PCOTA + 600 mg/kg BBR. Compared with NC, feeding PCAFB and PCOTA diets reduced average daily feed intake, weight gain, serum concentrations of superoxide dismutase, glutathione peroxidase, and the length and width of ileum villi (P < 0.05). At the same time, these parameters increased in birds fed PCAFB or PCOTA diets supplemented with 600 mg/kg of BBR (P < 0.05). Feeding PCAFB and PCOTA diets increased feed conversion ratio (FCR), serum aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and gamma-glutamyl transferase (GGT) activities, serum urea, and liver lesions compared with NC. By contrast, compared with PCAFB and PCOTA, adding 600 mg/kg BBR decreased FCR, AST, LDH, ALT, and GGT activities, urea, and liver lesions (P < 0.05). Overall, supplementation with 600 mg/kg BBR may improve growth performance, liver function, and antioxidant status of broilers fed diets contaminated with AFB and OTA.

Determination of ochratoxin A in edible pork offal: intra-laboratory validation study and estimation of the daily intake via kidney consumption in Belgium

Pork-derived products can contribute to the overall ochratoxin A (OTA) intake via carry-over from contaminated feed or via mould spoilage of meat products (salami, dry-cured ham, sausage). An analytical method using liquid chromatography coupled with mass spectrometry (LC-MS/MS) was developed and validated in accordance with the specifications laid down by European Commission. It offered quantification limits of 0.2 for kidney, liver and 0.4 μg/kg for black sausage. Spiking experiments of blank samples at 5-10 μg/kg showed recoveries ranging from 88 to 101%, 89 to 97% and 80 to 85% for kidney, liver and black sausage, respectively. The respective intra-laboratory repeatabilities ranged between 9.8-11.1%, 9.4-14.4% and 9.7-14.2%, and extended measurement uncertainties MU_(k = 2) were 33%, 35% and 43% for kidney, liver and black sausage. Next, the validated method was applied to kidney (110), liver (20) and black sausage (20) samples collected in Belgium in the period 2012-2019. Neither liver nor black sausage samples were contaminated with OTA. Kidney samples (37.3%) were OTA contaminated at the mean level of 0.22 ± 0.25 μg/kg (up to 1.91 μg/kg). These data combined with the offal consumption in the Belgian population revealed average daily OTA exposures ranged from 0.167 and 0.319 ng/kg bw for 3 age groups (3-9, 10-17 and 18-64 years). Taking into account, the OTA non-neoplastic and neoplastic effects, risk characterization assessed via the margin of exposure for reference endpoints revealed no potential health risk for the consumers. As the presence of low OTA content in foods together with other mycotoxins or derivatives may interactively potentiate its toxicity, monitoring of OTA and its metabolites in meat and meat by-products is advised.

Oxidative stress, hemato-immunological, and intestinal morphometry changes induced by ochratoxin A in APRI rabbits and the protective role of probiotics

This work studied the protective effects of Aspergillus awamori against ochratoxin A (OTA)-induced toxicity in APRI maternal line rabbits. A total number of 48 APRI line weanling rabbits (5 weeks) were divided into 4 groups (12 rabbits each) and fed the basal diet, 30 ppb/kg diet of OTA, 1 g/kg diet of A. awamori, and a mixture of OTA and A. awamori for 8 weeks. OTA reduced the final body weight and weight gain as well as the intestinal villi length and thickness, whereas increased the feed intake and feed conversion ratio. Rabbits fed diets with OTA showed significantly reduced crude protein, lipids, and fibers apparent digestibility coefficients (P < 0.05). The red blood cells and hemoglobin were significantly decreased in the OTA group comparing with the other groups (P < 0.05). The blood total protein and albumin displayed significantly lower levels by OTA than the other groups. In contrast, glucose, aspartate aminotransferase (AST), alkaline phosphatase (ALP), urea, and creatinine levels were significantly increased by OTA (P < 0.05). Phagocytic activity (PA) and phagocytic index (PI) showed significantly (P < 0.05) decreased levels in OTA-contaminated group, while rabbits fed A. awamori significantly showed the highest PA and PI levels (P < 0.05). Dietary A. awamori kept the levels of PA and PI in rabbits fed OTA significantly higher than those fed without A. awamori (P < 0.05) and not significantly different from the control group (P > 0.05). Catalase (CAT) and superoxide dismutase (SOD) displayed significantly lower levels in the OTA group, while malondialdehyde (MDA) was significantly higher than the other groups (P < 0.05). Rabbits fed OTA-contaminated diets displayed significantly lower CAT and SOD and higher MDA than rabbits fed OTA combined with A. awamori (P < 0.05). Our results indicated that dietary A. awamori ameliorated the damage in APRI rabbits fed OTA through alleviation of oxidative stress and immunity.

Aflatoxin and ochratoxin A residues in supplementary foods used for wild birds

Provision of supplementary food for garden birds is practiced on a large scale in multiple countries. While this resource has benefits for wild bird populations, concern has been expressed regarding the potential for contamination of foodstuffs by mycotoxins, and the implications this might have for wildlife health. We investigated whether aflatoxin (AF) and ochratoxin A (OA) residues are present in foodstuffs sold for wild bird consumption at point of sale in Great Britain using high pressure liquid chromatography analyses. The hypothesis that production of these mycotoxins occurs in British climatic conditions, or under storage conditions after the point of sale, was tested under experimental conditions but was not proved by our study. While the majority of peanut samples were negative for AF residues, 10% (10/98) of samples at point of sale and 11% (13/119) of those across the storage and climate exposure treatment replicates contained AFB₁ that exceeded the maximum permitted limit of 20 μg/kg. No significant difference was found in the detection of either mycotoxin between branded and non-branded products. The clinical significance, if any, of exposure of wild birds to mycotoxins requires further investigation. Nevertheless, the precautionary principle should be adopted and best practice steps to reduce the likelihood of wild bird exposure to mycotoxins are recommended.

Safety evaluation of Ochratoxin A and Citrinin after 28 days repeated dose oral exposure to Wistar rats

Mycotoxins, ochratoxin A (OTA), and citrinin (CTN) are toxic metabolites of filamentous fungi. The most common fungal species that produce OTA and CTN belong to genera Aspergillus, Penicillium, Fusarium, and Monascus, and these fungal species are found to be contaminant a wide range of grains, food, and food product. The aim of our study was to evaluate the sub-acute repeated dose oral toxicity of OTA and CTN in experimental rodents by following OECD test guidelines for testing chemicals no. 407 with minor modifications. Twenty-five rats of each sex were divided equally into five groups; vehicle control, OTA 25 μg/kg b. wt., OTA 100 μg/kg b. wt., CTN 25 μg/kg b.wt. and CTN 100 μg/kg b. wt. The results of this study showed no abnormal clinical signs during 28 days of the experimental period. We did not found any significant changes in body weight gain, food consumption pattern, organ weight, hematology except few parameters, and biochemical values in any of the treatment and control groups. However, histopathological observations revealed severe nephrotoxicity and mild follicular depletion in the spleen of 100 μg/kg b. wt. treated groups of both OTA and CTN mycotoxins. The findings of our study are of its first kind that reports the systemic toxicity of OTA and CTN oral exposure to laboratory rodents.

An In Silico Target Fishing Approach to Identify Novel Ochratoxin A Hydrolyzing Enzyme

Ochratoxin A (OTA), a mycotoxin that is of utmost concern in food and feed safety, is produced by fungal species that mainly belong to the Aspergillus and Penicillium genera. The development of mitigation strategies to reduce OTA content along the supply chains is key to ensuring safer production of food and feed. Enzyme-based strategies are among the most promising methods due to their specificity, efficacy, and multi-situ applicability. In particular, some enzymes are already known for hydrolyzing OTA into ochratoxin alpha (OTα) and phenylalanine (Phe), eventually resulting in detoxification action. Therefore, the discovery of novel OTA hydrolyzing enzymes, along with the advancement of an innovative approach for their identification, could provide a broader basis to develop more effective mitigating strategies in the future. In the present study, a hybrid in silico/in vitro workflow coupling virtual screening with enzymatic assays was applied in order to identify novel OTA hydrolyzing enzymes. Among the various hits, porcine carboxypeptidase B was identified for the first time as an effective OTA hydrolyzing enzyme. The successful experimental endorsement of findings of the workflow confirms that the presented strategy is suitable for identifying novel OTA hydrolyzing enzymes, and it might be relevant for the discovery of other mycotoxin- mitigating enzymes.

Risk assessment of the exposure to mycotoxins in dogs and cats through the consumption of commercial dry food

Dry feed for dogs and cats sold in Europe are mostly formulated with cereals and cereal by-products, so the contamination of this food with mycotoxins represents a potential risk for these pets. We analyzed a representation of the best-selling feed brands in Spain. The presence of Aflatoxins (B₁, B₂, G₁, and G₂), Ochratoxin A, T-2 and HT-2 toxins, Deoxynivalenol, Zearalenone, and Fumonisins (B₁ and B₂) was quantified, using immunoaffinity columns and LC-MS/MS. In general, mycotoxins were frequently and simultaneously (6-11) detected, with AFB₁, FB₁, FB₂, Deoxynivalenol, and HT-2 detected in 100% of the samples. However, the concentrations of most of them are among the lowest reported so far. Fumonisins were the exception since we report the highest concentrations to date, particularly in cat feed. We practically found no significant differences in the level of mycotoxin contamination in relation to the presumed quality of the feed. We also calculated the daily exposure, and evaluated the acute and chronic health risk posed by these feeds. None of the brands analyzed presented acute risk for any of the mycotoxins. However, the high levels of fumonisins found in some samples could become problematic, if there are hidden forms of them. This is also evident in relation to long-term risk, since in the case of fumonisins the level of exposure exceeds the tolerable daily intake level in 3.5 and 12 times, for dogs and cats respectively. The exposure levels to zearalenone and deoxynivalenol could also be of long-term concern, especially considering the possibility that the continuous exposure to several mycotoxins simultaneously might produce potentiated toxic effects as a result of their synergistic action. Further research on the potential adverse health effects deriving from chronic exposure to low doses of multi-mycotoxin mixtures in pets is needed.

Association Between Mycotoxin Exposure and Dietary Habits in Colorectal Cancer Development Among a Polish Population: A Study Protocol

Colorectal cancer (CRC) is one of the most common and lethal types of cancer worldwide. The developing of this disease includes many factors such as genetic, socioeconomic, environmental, and lifestyle factors, and nutrition habits. The aim of the study is the determination of zearalenone and its metabolite level in the biological samples of participants at risk of CRC, in relation to the nutrition data and information on the quality of life dependent on health. In the cohort clinical trial, 150 participants aged between 50 and 65 will be studied. The participants will be assigned into two groups depending on the colonoscopy result. Participants will be tested at dietary intake, quality of life, sleep time and quality, stress level as well as biochemical parameters of the blood. Moreover, in the biological samples, concentration of zearalenone and its metabolites (α-zearalenol and β-zearalenol) as well as the characteristics of gastrointestinal bacterial will be determined, and the end of the trial for both groups and their results will be compared. Taking into account the possible effect of mycotoxins and nutrition habits on the development of cancer, the results obtained may allow the formulation of new nutritional recommendations and reduce the development and occurrence of CRC.

Antibiotic residues and mycotoxins in raw milk in Punjab (India): a rising concern for food safety

The present study was envisaged with an aim to determine the occurrence of antibiotic residues; enrofloxacin, oxytetracycline, penicillin G, sulphamethoxazole and chloramphenicol as well as mycotoxins; aflatoxin M1 and ochratoxin A in raw milk samples collected from individual animals from dairy farms located in 9 districts of Punjab, India. A total of 168 raw milk samples were collected and analysed using commercially available competitive Enzyme linked immunosorbent assay kits. Out of these, 19 (11.3%) and 9 (5.4%) samples were found positive for antibiotic residues and mycotoxins, respectively. The milk samples were positive for enrofloxacin (4.8%), oxytetracycline (3.0%), penicillin G (3.0%) and sulphamethoxazole (0.6%) residues. The percentage of samples found above maximum residue limit established by Europen Union (EU)/Codex Alimentarius Commission (CAC) were 1.7%, 1.2% and 0.6% for enrofloxacin, oxytetracycline and penicillin G residues, respectively. Aflatoxin M1 was detected in 5.4% of monitored milk samples with 1.2% samples exceeded the established maximum levels of EU but were below the maximum levels established by CAC. The occurrence of antibiotic residues and mycotoxins in raw milk samples above maximum limits is a rising concern for food safety due to possibility of health risks to the consumers.

The footprints of mitochondrial impairment and cellular energy crisis in the pathogenesis of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and Fanconi's syndrome: A comprehensive review

Fanconi's Syndrome (FS) is a disorder characterized by impaired renal proximal tubule function. FS is associated with a vast defect in the renal reabsorption of several chemicals. Inherited and/or acquired conditions seem to be connected with FS. Several xenobiotics including many pharmaceuticals are capable of inducing FS and nephrotoxicity. Although the pathological state of FS is well described, the exact underlying etiology and cellular mechanism(s) of xenobiotics-induced nephrotoxicity, serum electrolytes imbalance, and FS are not elucidated. Constant and high dependence of the renal reabsorption process to energy (ATP) makes mitochondrial dysfunction as a pivotal mechanism which could be involved in the pathogenesis of FS. The current review focuses on the footprints of mitochondrial impairment in the etiology of xenobiotics-induced FS. Moreover, the importance of mitochondria protecting agents and their preventive/therapeutic capability against FS is highlighted. The information collected in this review may provide significant clues to new therapeutic interventions aimed at minimizing xenobiotics-induced renal injury, serum electrolytes imbalance, and FS.

Human milk mycotoxin contamination: smoking exposure and breastfeeding problems

Purpose: Mammalian milk may contain pollutants as a result of the maternal exposure. The objective was to determine the presence of selected mycotoxins in human milk and to investigate the effect of maternal characteristics on breastmilk mycotoxin levels and to examine the effect of mycotoxin contamination on lactational problems.Materials and methods: Information about maternal characteristics were taken by a questionnaire and breast milk samples were collected. Levels of aflatoxins M1 (AFM1), ochratoxins A (OTA), zearalenone (ZEN), Deoxynivalenol (DON) were determined by the solid-phase direct competitive enzyme immunoassay.Results: Median levels of breast milk AFM1 and OTA was 3.07 pg/mL and 1.38 ng/mL, respectively. ZEN and DON levels were higher than 0.3 ng/mL in 59% and higher than 10 ng/mL in 37.7%. After controlling for confounding factors, mothers who experienced "delayed onset of lactogenesis" had odds 3.33 times more for the highest quartile of ZEN and mothers with cracked nipples had odds 8.36 times more for the highest quartile of DON. Multiple regression analysis revealed that smoking exposure (environmental, maternal smoking versus never) significantly affected being in the highest quartile of OTA.Conclusion: Mycotoxin can pass to breast milk and smoking exposure of the mother may influence this situation. Mycotoxin exposure may lead to lactation problems. Maternal and infant health can be protected by preventing smoking exposure.

Development of an Antifungal and Antimycotoxigenic Device Containing Allyl Isothiocyanate for Silo Fumigation

The aims of this study were to evaluate the antifungal activity of the bioactive compound allyl isothiocyanate (AITC) against Aspergillus flavus (8111 ISPA) aflatoxins (AFs) producer and Penicillium verrucosum (D-01847 VTT) ochratoxin A (OTA) producer on corn, barley, and wheat. The experiments were carried out initially in a simulated silo system for laboratory scale composed of glass jars (1 L). Barley and wheat were contaminated with P. verrucosum and corn with A. flavus. The cereals were treated with a hydroxyethylcellulose gel disk to which 500 µL/L of AITC were added; the silo system was closed and incubated for 30 days at 21 °C. After that, simulated silos of 100 L capacity were used. Barley, wheat, and corn were contaminated under the same conditions as the previous trial and treated with disks with 5 mL of AITC, closed and incubated for 90 days at 21 °C. In both cases, the control test did not receive any antifungal treatment. The growth of the inoculated fungi and the reduction in the formation of AFs and OTA were determined. In the lab scale silo system, complete inhibition of fungal growth at 30 days has been observed. In corn, the reduction of aflatoxin B1 (AFB₁) was 98.5%. In the 100 L plastic drums, a significant reduction in the growth of A. flavus was observed, as well as the OTA formation in wheat (99.5%) and barley (92.0%).

Effect of Cinnamaldehyde on Morphological Alterations of Aspergillus ochraceus and Expression of Key Genes Involved in Ochratoxin A Biosynthesis

Ochratoxin A (OTA) is a potent nephrotoxic, hepatotoxic, and teratogenic compound which is a significant mycotoxin contaminates cereals during storage. Aspergillus ochraceus is the most common producer of OTA in cereals and cereal-derived products. Cinnamaldehyde is a natural substance derived from plant cinnamon playing an important role in the reduction of OTA contamination. In this study, the antifungal and antitoxigenic effect of cinnamaldehyde was investigated with its mechanisms of inhibition of fungal growth at the morphological and ultrastructural levels, and inhibition of OTA biosynthesis at the transcriptional level. Significant A. ochraceus growth was inhibited at 0.4⁻1.6 mmol/L with fumigation. A. ochraceus exposed to 0.4 mmol/L of cinnamaldehyde indicated irreversible harmful morphological and ultrastructural modifications such as the folding of the cell, the loss of integrity of the cell wall, the disruption of plasma membrane, the destruction of the mitochondria, and the absence of intracellular organelles. These alterations may be attributed to its inhibition of enzymatic reactions that regulate cell wall synthesis, thus disturbing the morphogenesis and growth of A. ochraceus. In the presence of cinnamaldehyde, the tested biosynthetic and regulatory genes like pks, nrps, veA, laeA and velB were highly downregulated. Moreover, the downregulation effect of cinnamaldehyde increased proportionally with the concentrations. These results suggest that the decrease of OTA production by cinnamaldehyde is attributed to the downregulation of the transcriptional levels of OTA biosynthetic and regulatory genes besides the inhibition of fungal growth. The study reveals the mechanisms of the antifungal and antitoxigenic activities of cinnamaldehyde against A. ochraceus, and further emphasizes that cinnamaldehyde could be a safe and effective natural agents against OTA contamination during cereals storage.

Effect of water activity, temperature, and incubation period on fungal growth and ochratoxin A production on Nyjer seeds

Aspergillus fresenii and Aspergillus sulphureus produce ochratoxin A (OTA), which is a secondary metabolite of Aspergillus and Penicillium species, with nephrotoxic effects and potential carcinogenic activity. The aim of this study was to determine the effects of temperature (20, 30, and 37 °C), water activity (0.82, 0.86, 0.90, 0.94, and 0.98 a_w), incubation period (5, 10, 15, and 30 days) on fungal growth, and OTA production by A. fresenii and A. sulphureus on Nyjer oil seeds. There was no fungal growth at 0.82 a_w. The two fungal species were able to produce OTA from the fifth day of incubation from 0.86 to 0.98 a_w and temperature 20 to 37 °C. Aspergillus fresenii produced the highest concentration of OTA (643 μg/kg) at 0.90 a_w and 37 °C within 15 days, while A. sulphureus produced the highest level of OTA (724 μg/kg) at 0.98 a_w and 20 °C within 10 days. The optimum water activity and temperature for the growth of both fungi were similar at 0.94 a_w and at 30 °C. There was statistically significant difference between the levels of OTA production among the two fungi. Overall, A. sulphureus produced significantly higher levels of OTA (p < 0.05). Higher temperature (37 °C) and 0.90-0.94 a_w were optimal for OTA production by A. fresenii. Our results show that Nyjer seeds can support the growth of A. fresenii and A. sulphureus and OTA production, and the two species had similar temperature and water activity requirements for growth but different requirements for OTA production on Nyjer seeds.

Low Doses of Ochratoxin-A Decrease IgY and IgA Production in Broiler Chicks

The mycotoxin, ochratoxin-A (OTA), produced by some fungi, and is a natural contaminant of many foods and animal feeds worldwide. Due to its toxic effects, the recommended maximum daily intake of OTA for poultry feeds is 0.1 mg OTA/kg (ECR2006/575/EC); this dose does not induce changes in hepatic/renal parameters, but decreases thymus size and serum globulin concentrations. Accordingly, in this study, we assessed quantitatively the total circulating IgY and IgA serum levels, in chicks consuming a 0.1 mg OTA/kg diet (limit) and higher doses (0.3–1.1 mg OTA/kg diet) for 14 or 21 days. We also evaluated other immunological parameters (thymus, bursa of Fabricius, and spleen weights and leukocyte profiles) at day 21. Decreased IgY serum levels were observed in all OTA-treated groups (p < 0.05). In the low-dose group, IgA levels were decreased on day 21, but not on day 14. The size of the thymus and the bursa of Fabricius was decreased in all OTA-treated groups (p < 0.05), whereas reduced spleen size and altered leukocyte profiles were detected only in the high-dose group (p < 0.05). We concluded that chronic exposure to OTA, even at the recommended highest dose, affected IgY and IgA production in chicks.

Contaminants in Foods of Animal Origin in Cameroon: A One Health Vision for Risk Management "from Farm to Fork"

Foods of animal origin represent an important share in the diet of Cameroonian populations. Cameroon is known to be a food basket in the west and central Africa sub-region, and an important supplier of foods on the international markets. In the meantime, food importation is continuously increasing to meet the high demand of a more westernized segment of the population. Cereals, fish, sea products, eggs, honey, shrimps, chicken, and feed ingredients are important share in the international trade of agricultural products. Few controls are made on the quality and safety of these products. Certain safety standards do exist but are still yet to be enforced. Inspections done so far by regulatory authorities are partial and do not cover important hazards that require laboratory analysis. The increasing awareness of population, the burden of new types of disease, as well as the recurrence of food scandals have recently launched a scientific and population debate on the contribution of foods items, especially those of animal origin, to the toxic exposure of food producing animals and humans. This paper critically reviews the occurrence of toxicants in most consumed foods of animal origin in Cameroon. This study included the most consumed food of animal origin, identified during the national household budget survey and contributing to 8.1% of the total diet of an individual. Data evaluated suggest an important contamination by toxic metals, mycotoxins, veterinary drugs’ residues, and pesticides. The current national legal framework is briefly analyzed to explore possible intervention measures in the frame of the One Health approach.

Estimation of ochratoxin A in poultry feed and its ingredients with special reference to temperature conditions

1. The present study was designed to analyse ochratoxin A (OTA) in poultry feed samples (mixed types) along with different poultry feed ingredients collected from different farms and market of Lahore, Pakistan. 2. The whole year (2012-2013) was divided into three sub-periods depending upon environmental conditions, that is, July-October (hot and humid), November-February (winter) and March-June (moderate). During each sub-period 120 samples were collected for each feed and each ingredient constituting a total of 840 samples (120x7 of feed and feed ingredients in each sub-period). 3. The results of this study indicated that the incidence of OTA-positive samples was highest in July-October followed by that during March-June while the incidence was minimum during November-February. Similarly, the largest number of samples was below the maximum tolerable level (MTL) during November-February followed by March-June while the least number of samples was below MTL during hot weather (July-October). 4. This is the first elaborative study regarding the levels of OTA in poultry feed and its ingredients collected from Lahore, Pakistan.

Biomolecular detection at ssDNA-conjugated nanoparticles by nano-impact electrochemistry

We describe the use of ssDNA functionalized silver nanoparticle (AgNP) probes for quantitative investigation of biorecognition and real time detection of biomolecular targets using nano-impact electrochemistry. The method is based on measurements of the individual collision events between ssDNA aptamer-functionalized AgNPs and a carbon fiber miroelectrode (CFME). Specific binding events of target analyte induced collision frequency changes enabling ultrasensitive detection of the aptamer target in a single step. These changes are assigned to the surface coverage of the NP by the ssDNA aptamers and subsequent conformational changes of the aptamer probe which affect the electron transfer between the NP and the electrode surface. The method enables sensitive and selective detection of ochratoxin A (OTA), chosen here as a model target, with a limit of detection of 0.05nM and a relative standard deviation of 4.9%. The study provides a means of characterizing bioconjugation of AgNPs with aptamers and assessing biomolecular recognition events with high sensitivity and without the use of exogenous reagents or enzyme amplification steps. This methodology can be broadly applicable to other bioconjugated systems, biosensing and related bioanalytical applications.

Review on Mycotoxin Issues in Ruminants: Occurrence in Forages, Effects of Mycotoxin Ingestion on Health Status and Animal Performance and Practical Strategies to Counteract Their Negative Effects

Ruminant diets include cereals, protein feeds, their by-products as well as hay and grass, grass/legume, whole-crop maize, small grain or sorghum silages. Furthermore, ruminants are annually or seasonally fed with grazed forage in many parts of the World. All these forages could be contaminated by several exometabolites of mycotoxigenic fungi that increase and diversify the risk of mycotoxin exposure in ruminants compared to swine and poultry that have less varied diets. Evidence suggests the greatest exposure for ruminants to some regulated mycotoxins (aflatoxins, trichothecenes, ochratoxin A, fumonisins and zearalenone) and to many other secondary metabolites produced by different species of Alternaria spp. (e.g., AAL toxins, alternariols, tenuazonic acid or 4Z-infectopyrone), Aspergillus flavus (e.g., kojic acid, cyclopiazonic acid or β-nitropropionic acid), Aspergillus fuminatus (e.g., gliotoxin, agroclavine, festuclavines or fumagillin), Penicillium roqueforti and P. paneum (e.g., mycophenolic acid, roquefortines, PR toxin or marcfortines) or Monascus ruber (citrinin and monacolins) could be mainly related to forage contamination. This review includes the knowledge of mycotoxin occurrence reported in the last 15 years, with special emphasis on mycotoxins detected in forages, and animal toxicological issues due to their ingestion. Strategies for preventing the problem of mycotoxin feed contamination under farm conditions are discussed.

Functional Characterization of New Polyketide Synthase Genes Involved in Ochratoxin A Biosynthesis in Aspergillus Ochraceus fc-1

Ochratoxin A (OTA), a potentially carcinogenic mycotoxin which contaminates grains, is produced by several Aspergillus species. A comparative sequence analysis of the OTA-producing Aspergillus ochraceus fc-1 strain and other Aspergillus species was performed. Two new OTA-related polyketide synthase (PKS) (AoOTApks) genes were identified. The predicted amino acid sequence of AoOTApks-1 displayed high similarity to previously identified PKSs from OTA-producing A. carbonarius ITEM 5010 (67%; [PI] No. 173482) and A. niger CBS 513.88 (62%; XP_001397313). However, the predicted amino acid sequence of AoOTApks-2 displayed lower homology with A. niger CBS 513.88 (38%) and A. carbonarius ITEM 5010 (28%). A phylogenetic analysis of the β-ketosynthase and acyl-transferase domains of the AoOTApks proteins indicated that they shared a common origin with other OTA-producing species, such as A. carbonarius, A. niger, and A. westerdijkiae. A real-time reverse-transcription PCR analysis showed that the expression of AoOTApks-1 and -2 was positively correlated with the OTA concentration. The pks gene deleted mutants ∆AoOTApks-1 and ∆AoOTApks-2 produced nil and lesser OTA than the wild-type strain, respectively. Our study suggests that AoOTApks-1 could be involved in OTA biosynthesis, while AoOTApks-2 might be indirectly involved in OTA production.

Label-free impedimetric aptasensor for ochratoxin-A detection using iridium oxide nanoparticles

In this article, a novel aptasensor for ochratoxin A (OTA) detection based on a screen-printed carbon electrode (SPCE) modified with polythionine (PTH) and iridium oxide nanoparticles (IrO2 NPs) is presented. The electrotransducer surface is modified with an electropolymerized film of PTH followed by the assembly of IrO2 NPs on which the aminated aptamer selective to OTA is exchanged with the citrate ions surrounding IrO2 NPs via electrostatic interactions with the same surface. Electrochemical impedance spectroscopy (EIS) in the presence of the [Fe(CN)6](-3/-4) redox probe is employed to characterize each step in the aptasensor assay and also for label-free detection of OTA in a range between 0.01 and 100 nM, obtaining one of the lowest limits of detection reported so far for label-free impedimetric detection of OTA (14 pM; 5.65 ng/kg). The reported system also exhibits a high reproducibility, a good performance with a white wine sample, and an excellent specificity against another toxin present in such sample.

Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models

The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease in cell viability, but at the same time increased the OTA-DNA adducts formation. These findings indicate the need for an in-depth characterisation of yeast-based products used as mycotoxin-mitigating feed additives, in in vivo models with target animal species taking into account not only their ability to sequester toxins in the gastrointestinal tract but also their potential effects on the biotransformation of mycotoxins.

Impedimetric aptasensor for ochratoxin A determination based on Au nanoparticles stabilized with hyper-branched polymer

An impedimetric aptasensor for ochratoxin A (OTA) detection has been developed on the base of a gold electrode covered with a new modifier consisting of electropolymerized Neutral Red and a mixture of Au nanoparticles suspended in the dendrimeric polymer Botlorn H30®. Thiolated aptamer specific to OTA was covalently attached to Au nanoparticles via Au-S bonding. The interaction of the aptamer with OTA induced the conformational switch of the aptamer from linear to guanine quadruplex form followed by consolidation of the surface layer and an increase of the charge transfer resistance. The aptasensor makes it possible to detect from 0.1 to 100 nM of OTA (limit of detection: 0.02 nM) in the presence of at least 50 fold excess of ochratoxin B. The applicability of the aptasensor for real sample assay was confirmed by testing spiked beer samples. The recovery of 2 nM OTA was found to be 70% for light beer and 78% for dark beer.

Immobilization of mycotoxins on modified nanodiamond substrates

The effectiveness of modified nanodiamonds (NDs) for the adsorption of mycotoxins, aflatoxin B1 (AfB1) and ochratoxin A (OTA), are investigated in this paper. Binding and release mechanisms of the mycotoxins were addressed using an assortment of NDs modified by different surface treatments, including carboxylation, hydrogenation and hydroxylation, followed by isolating NDs of different sizes. Results indicate that AfB1 adsorption on NDs is directly related to aggregate size, whereas OTA adsorption is primarily centered upon electrostatic interactions that depend on the types of surface functional groups on the ND. Findings show that modified NDs with small aggregation sizes (∼40 nm) have greater adsorption capacities for AfB1 than yeast cells walls and untreated NDs from various vendors, but comparable to activated charcoal. In OTA studies, positively charged NDs outperformed clay minerals, which are well-known and efficient sorbents for mycotoxins. Furthermore, ND adsorption capacities can be preserved in a wide range of pH.

Biochemical changes in pig serum after ochratoxin A exposure

The objective of this study was to investigate the effect of ochratoxin A (OTA) on serum biochemical parameters of pigs during subchronic treatment with 300 μg OTA/kg of feed for 30 days. OTA treatment resulted in significantly higher (p < 0.05) serum levels of creatinine, urea, potassium and alkaline phosphatase, and significantly lower levels of glucose and total protein. These changes in serum biochemical parameters in treated pigs were indicative of impaired liver and kidney function caused by OTA exposure.

Reflectometric interference spectroscopy (RIfS) as a new tool to measure in the complex matrix milk at low analyte concentration

Measurements in complex matrices like milk still present a challenge in biosensor development. This is especially important when using a label-free detection method or when measuring low analyte concentrations. The direct optical method reflectometric interference spectroscopy (RIfS) was used for investigating matrix effects in immunoassay development. Furthermore, approaches to reduce these effects have been established. As a model system, the hormone testosterone has been chosen because this immunoassay has been well characterized in buffer. In a first step, the immunoassay for the detection of testosterone in buffer was improved beyond former published results. Therefore, the sensor surface was optimized, resulting in a fivefold lower limit of detection (70.2 ng L(-1)) and limit of quantification (130.0 ng L(-1)). Additionally, the assay time could be reduced to 15 min. Consequently, we used this improved assay to investigate matrix effects of whole pasteurized bovine milk. To minimize these effects, the surface chemistry was adapted and a suitable evaluation method was established, reducing the effects of Tyndall scattering and nonspecific binding to the sensor surface. These improvements allow for very reliable quantitative measurements in milk. The assay developed required no sample pretreatment and allowed for the regeneration of the sensor surface so that calibration could be performed on one chip. The calibration in milk (3.5% fat) resulted in a limit of detection of 94.4 ng L(-1) and a limit of quantification of 229.3 ng L(-1). Furthermore, recovery rates between 70% and 120% could be obtained. Thus, for the first time, an analyte in the matrix milk was successfully quantified with RIfS at low concentrations.

Comparison of manual and automatic sampling for monitoring ochratoxin A in barley grain

Automatic and manual sampling for ochratoxin A (OTA) in barley grain was compared under industrial conditions considering sampling uncertainty as well as practical and technical aspects. Ten tonnes of barley inoculated with Penicillium verrucosum were incubated until the OTA concentration reached approximately 15 µg kg(-1) and sampled with manual and automatic sampling. A nested experimental design and ANOVA was used to estimate variance components from sampling, sample reduction, sample preparation and analysis. Manual sampling resulted in a high sampling uncertainty and OTA concentrations in aggregate samples ranged from 2 to 80 µg kg(-1). When aggregate samples were formed by automatic sampling the uncertainty arising from nugget effects and spatial distribution was practically eliminated. Results from this study show that an automatic sampler mounted after a mixer or conveyer can provide representative samples of OTA from a moving stream of barley. Automatic sampling might present a practical and economical alternative to manual sampling for feed mill operators when monitoring low levels of mycotoxins in grain or other commodities. Despite careful precautions, sample preparation and analysis resulted in a relative uncertainty of ±40% (p = 0.95), which was attributed to the sub-sampling following the two grinding steps. Size fractionation of the coarsely ground barley showed that 40% of the total amount of OTA was present in a small fraction of fine particles with a strong tendency to aggregate or stick to equipment and containers. Thus, in order to take advantage of the automatic sampling, it is crucial to apply an appropriate sub-sampling to prevent segregation of particles which may affect the OTA measurements.