Deoxynivalenol exposure assessment in young children in Tanzania

Scope: This study assessed deoxynivalenol (DON) exposure in children from three geographic locations within Tanzania, over three time points in 1 year, using a urinary biomarker of exposure.

Methods and results: A total of 166 children aged 6-14 months were studied at a maize harvest and followed up twice at 6-month intervals. On two consecutive days, morning urine was collected from each child and urinary DON was measured using an LC-MS method, with and without beta-glucuronidase hydrolysis in order to assess free DON (fDON) and glucuronide DON. Overall, urinary DON increased significantly along with the three visits (geometric mean 1.1, 2.3, and 5.7 ng/mL, at visits 1, 2, and 3, respectively, p <0.01). fDON was 22% of urinary total DON. Urinary DON excretion rate was 74% in village Kikelelwa based on food DON level and food consumption. Assuming 360 mL of urine excreted per day, 10, 19, and 29% of children at visits 1, 2, and 3, respectively, exceeded the provisional maximum tolerable daily intake of 1000 ng/kg b.w./day.

Conclusion: Young children in Tanzania are chronically exposed to DON due to eating contaminated maize, although exposure levels varied markedly by region and season.

Anthelmintic drug residues in beef: UPLC-MS/MS method validation, European retail beef survey, and associated exposure and risk assessments

Anthelmintic drugs are widely used to control parasitic infections in cattle. The ProSafeBeef project addressed the need for data on the exposure of European consumers of beef to potentially harmful drug residues. A novel analytical method based on matrix solid-phase dispersive extraction and ultra-performance liquid chromatography-tandem mass spectrometry was validated for 37 anthelmintic drugs and metabolites in muscle (assay decision limits, CCa, = 0.15-10.2 µg kg -1). Seven European countries (France, Spain, Slovenia, Ireland, Italy, Belgium and Portugal) participated in a survey of retail beef purchased in local shops. Of 1061 beef samples analysed, 26 (2.45%) contained detectable residues of anthelmintic drugs (0.2-171 µg kg -1), none above its European Union maximum residue limit (MRL) or action level. Residues detected included closantel, levamisole, doramectin, eprinomectin, moxidectin, ivermectin, albendazole and rafoxanide. In a risk assessment applied to mean residue concentrations across all samples, observed residues accounted for less than 0.1% of the MRL for each compound. An exposure assessment based on the consumption of meat at the 99th percentile of consumption of adults in 14 European countries demonstrated that beef accounted for less than 0.02% of the acceptable daily intake for each compound in each country. This study is the first of its kind to apply such a risk-based approach to an extensive multi-residue survey of veterinary drug residues in food. It has demonstrated that the risk of exposure of the European consumer to anthelmintic drug residues in beef is negligible, indicating that regulation and monitoring is having the desired effect of limiting residues to non-hazardous concentrations. © 2012 Copyright Taylor and Francis Group, LLC.

Determining mycotoxins and mycotoxigenic fungi in food and feed:Developing biomarkers of human exposure to mycotoxins

Exposure assessment is a critical part of epidemiological studies into the effect of mycotoxins on human health. Whilst exposure assessment can be made by estimating the quantity of ingested toxins from food analysis and questionnaire data, the use of biological markers (biomarkers) of exposure can provide a more accurate measure of individual level of exposure in reflecting the internal dose. Biomarkers of exposure can include the excreted toxin or its metabolites, as well as the products of interaction between the toxin and macromolecules such as protein and DNA. Samples in which biomarkers may be analysed include urine, blood, other body fluids and tissues, with urine and blood being the most accessible for human studies. Here we describe the development of biomarkers of exposure for the assessment of three important mycotoxins; aflatoxin, fumonisin and deoxynivalenol. A number of different biomarkers and methods have been developed that can be applied to human population studies, and these approaches are reviewed in the context of their application to molecular epidemiology research.

A pilot survey for Fusarium mycotoxin biomarkers in women from Golestan, northern Iran

Fusarium mycotoxins are frequent contaminants of cereals in many world regions, and are suggested risk factors for various acute and chronic human diseases. To date a lack of exposure tools has restricted epidemiological studies of the potential health effects. Recently established exposure biomarkers for deoxynivalenol (DON) and fumonisins are now available and here a pilot biomarker survey of 110 women (aged 39 to 72 years) from Golestan, northern Iran was conducted on samples collected at one time point during August-September 2007. Urinary DON and DON-glucuronide combined were detected frequently (79/110, 72%), mean 1.3 ng DON/ml urine, range not detected (nd)-6.5 ng/ml; mean creatinine adjusted levels were 1.5 ng DON/mg creatinine, range nd-7.1 ng/mg). Neither urinary de-epoxy DON (DOM-1) and DOM-1 glucuronide combined, nor urinary fumonisin B-1 were detected. This study is the first reported biomarker based exposure assessment of DON and fumonisins in this region. Overall DON exposure at this time point appears modest compared to other world regions where data are available.

Association between tortilla consumption and human urinary fumonisin B1 levels in a Mexican population

Fumonisins are mycotoxins produced by Fusarium spp. and commonly contaminate maize and maize products worldwide. Fumonisins are rodent carcinogens and have been associated with human esophageal cancer. However, the lack of a valid exposure biomarker has hindered both the assessment of human exposure and the evaluation of disease risk. A sensitive liquid chromatography-mass spectrometry method to measure urinary fumonisin B1 (FB1) following extraction on Oasis MAX cartridges was established and applied to urine samples from women in a cohort recruited in Morelos County, Mexico. Urinary FB1 was compared with dietary information on tortilla consumption. FB1 recovery in spiked samples averaged 94% as judged by deuterium-labeled FB1 internal standard. Urinary FB1 was determined in 75 samples from women selected based on low, medium, or high consumption of maize-based tortillas. The geometric mean (95% confidence interval) of urinary FB1 was 35.0 (18.8-65.2), 63.1 (36.8-108.2), and 147.4 (87.6-248.0) pg/mL and the frequency of samples above the detection limit (set at 20 pg FB1/mL urine) was 45%, 80%, and 96% for the low, medium, and high groups, respectively. Women with high intake had a 3-fold higher average FB1 levels compared with the "low intake" group (F = 7.3; P = 0.0015). Urinary FB1 was correlated with maize intake (P-trend = 0.001); the correlation remained significant after adjusting for age, education, and place of residence. This study suggests that measurement of urinary FB1 is sufficiently sensitive for fumonisin exposure assessment in human populations and could be a valuable tool in investigating the associated health effects of exposure.

Estimation of Mycobacterium avium subsp. paratuberculosis load in raw bulk tank milk in Emilia-Romagna Region (Italy) by qPCR

Consumption of milk and dairy products is considered one of the main routes of human exposure to Mycobacterium avium subsp. paratuberculosis (MAP). Quantitative data on MAP load in raw cows’ milk are essential starting point for exposure assessment. Our study provides this information on a regional scale, estimating the load of MAP in bulk tank milk (BTM) produced in Emilia-Romagna region (Italy). The survey was carried out on 2934 BTM samples (88.6% of the farms herein present) using two different target sequences for qPCR (f57 and IS900). Data about the performances of both qPCRs are also reported, highlighting the superior sensitivity of IS900-qPCR. Seven hundred and eighty-nine samples tested MAP-positive (apparent prevalence 26.9%) by IS900 qPCR. However, only 90 of these samples were quantifiable by qPCR. The quantifiable samples contained a median load of 32.4 MAP cells mL−1 (and maximum load of 1424 MAP cells mL−1). This study has shown that a small proportion (3.1%) of BTM samples from Emilia-Romagna region contained MAP in excess of the limit of detection (1.5 × 101 MAP cells mL−1), indicating low potential exposure for consumers if the milk subsequently undergoes pasteurization or if it is destined to typical hard cheese production.

Risk assessment of neonatal excipient exposure:Lessons from food safety and other areas

Newborn babies can require significant amounts of medication containing excipients intended to improve the drug formulation. Most medicines given to neonates have been developed for adults or older children and contain excipients thought to be safe in these age groups. Many excipients have been used widely in neonates without obvious adverse effects. Some excipients may be toxic in high amounts in which case they need careful risk assessment. Alternatively, it is conceivable that ill-founded fears about excipients mean that potentially useful medicines are not made available to newborn babies. Choices about excipient exposure can occur at several stages throughout the lifecycle of a medicine, from product development through to clinical use. Making these choices requires a scalable approach to analysing the overall risk. In this contribution we examine these issues.

Challenging conventional risk assessment with respect to human exposure to multiple food contaminants in food: A case study using maize

Mycotoxins and heavy metals are ubiquitous in the environment and contaminate many foods. The widespread use of pesticides in crop production to control disease contributes further to the chemical contamination of foods. Thus multiple chemical contaminants threaten the safety of many food commodities; hence the present study used maize as a model crop to identify the severity in terms of human exposure when multiple contaminants are present. High Content Analysis (HCA) measuring multiple endpoints was used to determine cytotoxicity of complex mixtures of mycotoxins, heavy metals and pesticides. Endpoints included nuclear intensity (NI), nuclear area (NA), plasma membrane permeability (PMP), mitochondrial membrane potential (MMP) and mitochondrial mass (MM). At concentrations representing legal limits of each individual contaminant in maize (3. ng/ml ochratoxin A (OTA), 1. μg/ml fumonisin B1 (FB1), 2. ng/ml aflatoxin B1 (AFB1), 100. ng/ml cadmium (Cd), 150. ng/ml arsenic (As), 50. ng/ml chlorpyrifos (CP) and 5. μg/ml pirimiphos methyl (PM), the mixtures (tertiary mycotoxins plus Cd/As) and (tertiary mycotoxins plus Cd/As/CP/PM) were cytotoxic for NA and MM endpoints with a difference of up to 13.6% (. p≤. 0.0001) and 12% (. p≤. 0.0001) respectively from control values. The most cytotoxic mixture was (tertiary mycotoxins plus Cd/As/CP/PM) across all 4 endpoints (NA, NI, MM and MMP) with increases up to 61.3%, 23.0%, 61.4% and 36.3% (. p≤. 0.0001) respectively. Synergy was evident for two endpoints (NI and MM) at concentrations contaminating maize above legal limits, with differences between expected and measured values of (6.2-12.4% (. p≤. 0.05-. p≤. 0.001) and 4.5-12.3% (. p≤. 0.05-. p≤. 0.001) for NI and MM, respectively. The study introduces for the first time, a holistic approach to identify the impact in terms of toxicity to humans when multiple chemical contaminants are present in foodstuffs. Governmental regulatory bodies must begin to contemplate how to safeguard the population when such mixtures of contaminants are found in foods and this study starts to address this critical issue.

Use of the multispecies freshwater biomonitor to assess behavioral changes of Corophium volutator (Pallas, 1766) (Crustacea, Amphipoda) in response to toxicant exposure in sediment

Automated sediment toxicity testing and biomonitoring has grown rapidly. This study tested the suitability of the marine amphipod Corophium volutator (Pallas, 1766) for sediment biomonitoring using the Multispecies Freshwater Biomonitor (MFB). Two experiments were undertaken to (1) characterize individual behaviors of C. volutator using the MFB and (2) examine behavioral changes in response to sediment spiked with the pesticide Bioban. Four behaviors were visually identified (walking, swimming, grooming and falling) and characterized in the MFB as different patterns of locomotor activity (0-2 Hz range). Ventilation was not visually observed but was detected by the MFB (2-8 Hz). No clear diel activity patterns were detected. The MFB detected an overall increase in C. volutator locomotor activity after Bioban addition to the sediments (56, 100, 121 mg kg(-1)). C. volutator was more active (both locomotion and ventilation) in the water column than the spiked sediment. C. volutator appears a sensitive and appropriate species for behavioral sediment toxicity assessment and biomonitoring. (c) 2005 Elsevier Inc. All rights reserved.

Toxicity assessment of xenobiotic contaminated groundwater using lux modified Pseudomonas fluorescens

A bacterial bioassay, suitable for rapid screening to assess the relative toxicity of xenobiotic contaminated groundwater has been developed. The quantitative bioassay utilizes a decline in luminescence of the lux marked soil bacterium Pseudomonas fluorescens on exposure to contaminated groundwaters from which effective concentration (EC) values can be assessed and compared. P. fluorescens was most sensitive to semi-volatile organics in groundwaters but there was no correlation between EC value and chemical content. The sensitivity and reproducibility of the P. fluorescens bioassay was compared with that of Microtox and results showed that mean EC₅₀ values for diluted ground water replicate samples were 20% and 18% respectively. This suggested that the P. fluorescens bioassay was as applicable to groundwater screening as the widely used Microtox bioassay.

Welfare risk assessment:The benefits and common pitfalls

Risk is defined as a situation involving exposure to danger. Risk assessment by nature characterises the probability of a negative event occurring and quantifies the consequences of such an event. Risk assessment is increasingly being used in the field of animal welfare as a means of drawing comparisons between multiple welfare problems within and between species and identifying those that should be prioritised by policy-makers, either because they affect a large proportion of the population or because they have particularly severe consequences for those affected. The assessment of risk is typically based on three fundamental factors: intensity of consequences, duration affected by consequences and prevalence. However, it has been recognised that these factors alone do not give a complete picture of a hazard and its associated consequences. Rather, to get a complete picture, it is important to also consider information about the hazard itself: probability of exposure to the hazard and duration of exposure to the hazard. The method has been applied to a variety of farmed species (eg poultry, dairy cows, farmed fish), investigating housing, husbandry and slaughter procedures, as well as companion animals, where it has been used to compare inherited defects in pedigree dogs and horses. To what extent can we trust current risk assessment methods to get the priorities straight? How should we interpret the results produced by such assessments? Here, the potential difficulties and pitfalls of the welfare risk assessment method will be discussed: (i) the assumption that welfare hazards are independent; (ii) the problem of quantifying the model parameters; and (iii) assessing and incorporating variability and uncertainty into welfare risk assessments. © 2012 Universities Federation for Animal Welfare.

Fumonisin B-1 as a Urinary Biomarker of Exposure in a Maize Intervention Study Among South African Subsistence Farmers

Background: The consumption of maize highly contaminated with carcinogenic fumonisins has been linked to high oesophageal cancer rates. The aim of this study was to validate a urinary fumonisin B-1 (UFB1) biomarker as a measure of fumonisin exposure and to investigate the reduction in exposure following a simple and culturally acceptable intervention.

Methods: At baseline home-grown maize, maize-based porridge, and first-void urine samples were collected from female participants (n = 22), following their traditional food practices in Centane, South Africa. During intervention the participants were trained to recognize and remove visibly infected kernels, and to wash the remaining kernels. Participants consumed the porridge prepared from the sorted and washed maize on each day of the two-day intervention. Porridge, maize, and urine samples were collected for FB1 analyses.

Results: The geometric mean (95% confidence interval) for FB1 exposure based on porridge (dry weight) consumption at baseline and following intervention was 4.84 (2.87-8.14) and 1.87 (1.40-2.51) mg FB1/kg body weight/day, respectively, (62% reduction, P < 0.05). UFB1C, UFB1 normalized for creatinine, was reduced from 470 (295-750) at baseline to 279 (202-386) pg/mg creatinine following intervention (41% reduction, P = 0.06). The UFB1C biomarker was positively correlated with FB1 intake at the individual level (r - 0.4972, P < 0.01). Urinary excretion of FB1 was estimated to be 0.075% (0.054%-0.104%) of the FB1 intake.

Conclusion: UFB1 reflects individual FB1 exposure and thus represents a valuable biomarker for future fumonisin risk assessment.

Impact: The simple intervention method, hand sorting and washing, could positively impact on food safety and health in communities exposed to fumonisins. Cancer Epidemiol Biomarkers Prev; 20(3); 483-9. (C)2011 AACR.

Simple intervention method to reduce fumonisin exposure in a subsistence maize-farming community in South Africa

In the Centane magisterial area of South Africa, high rates of oesophageal cancer have been associated with home-grown maize contaminated with fumonisins. The aim of this study was to implement a simple intervention method to reduce fumonisin exposure in a subsistence-farming community. The hand-sorting and washing procedures, based on traditional maize-based food preparation practices, were previously customised under laboratory-controlled conditions. Home-grown maize and maize-based porridge collected at baseline were analysed for fumonisin B1, B2 and B3. The geometric mean (95% confidence interval) of fumonisin contamination in the home-grown maize at baseline was 1.67 (1.21-2.32) mg kg-1 and 1.24 (0.75-2.04) mg kg -1 (dry weight) in the porridge. Fumonisin exposure was based on individual stiff porridge consumption and the specific fumonisin levels in the porridge (dry weight) consumed. Porridge (dry weight) consumption at baseline was 0.34 kg day-1 and fumonisin exposure was 6.73 (3.90-11.6) mu g kg-1 body weight day-1. Female participants (n = 22) were trained to recognise and remove visibly infected/damaged kernels and to wash the remaining maize kernels. The discarded kernels represented 3.9% by weight and the fumonisins varied from 17.1 to 76.9 mg kg-1. The customised hand-sorting and washing procedures reduced fumonisin contamination in the maize and porridge by 84 and 65%, respectively. The intervention reduced fumonisin exposure by 62% to 2.55 (1.94-3.35) mu g kg-1 body weight day-1. This simple intervention method has the potential to improve food safety and health in subsistence-farming communities consuming fumonisin-contaminated maize as their staple diet.