Strategies to reduce exposure of fumonisins from complementary foods in rural Tanzania

Multi-mycotoxin exposure of children (0-24 months) in rural maize-subsistence farming areas of the Eastern Cape Province, South Africa

In South Africa, child malnutrition is highly prevalent among children from in rural areas mostly at risk. In the Eastern Cape (EC) Province, maize is commonly used as complementary and weaning food. Previous studies conducted in parts of EC have indicated high levels of fumonisin B (FB) mycotoxins in home-grown maize, as well as the co-occurrence of other Fusarium mycotoxins, such as deoxynivalenol (DON) and zearalenone (ZEN). A cross-sectional study of children below 24 months was conducted in rural maize-subsistence farming areas in Centane, EC to determine mycotoxin exposure. Home-grown maize samples (n=171) were collected from households in the study area and analysed by LC-MS/MS for FB, DON and ZEN. Food intakes of 129 children were quantified using a validated quantitative food frequency questionnaire (QFFQ). Individual raw maize consumption was calculated using recipes from the QFFQ. Probable daily intakes (PDIs) for each mycotoxin were determined using a deterministic approach and were compared to the respective mycotoxins’ provisional maximum tolerable daily intake (PMTDI). The numerical means for total FB (sum of fumonisin B1, B2 and B3), DON and ZEN levels in home-grown maize were 1,035, 24.5 and 31.0 μg/kg, respectively. Mean daily maize intakes of children ranged from 2-321 g/day and increased with age. The mean PDIs for total FB, DON and ZEN were 8.4, 0.2 and 0.3 μg/kg body weight (bw)/day, respectively. Exposures stratified by age indicated persistent high mean PDIs for total FB, above the PMTDI of 2 μg/kg bw/day, ranging between 5.0-11.6 μg/kg bw/day. Mean exposure to DON and ZEN were below their relevant PMTDIs (1 and 0.5 μg/kg bw/day, respectively). Individually, 81 and 13% of children had exposures above the PMTDI for total FB and for ZEN, respectively. Results confirm the magnitude of FB exposure among vulnerable groups from rural maize subsistence farming areas in EC.

Biomarker Evaluation and Toxic Effects of an Acute Oral and Systemic Fumonisin Exposure of Pigs with a Special Focus on Dietary Fumonisin Esterase Supplementation

The mycotoxin fumonisin B1 (FB1) is a frequent contaminant of feed. It causes a disruption of sphingolipid metabolism and pulmonary, hepatic, and immunological lesions in pigs depending on the exposure scenario. One sensitive biomarker for FB1 exposure is the sphinganine (Sa) to sphingosine (So) ratio in blood. The fumonisin esterase FumD, which can be used as a feed additive, converts FB1 into the much less toxic metabolite hydrolyzed FB1 (HFB1). We conducted a single-dose study with barrows allocated to one of five treatments: (1) control (feed, 0.9% NaCl intravenously iv), (2) 139 nmol FB1 or (3) HFB1/kg BW iv, (4) 3425 nmol FB1/kg BW orally (po), or (5) 3321 nmol FB1/kg BW and 240 U FumD/kg feed po. The Sa/So ratio of iv and po FB1 administered groups was significantly elevated in blood and Liquor cerebrospinalis, but no fumonisin-associated differences were reflected in other endpoints. Neither clinical lung affections nor histopathological pulmonary lesions were detected in either group, while some parameters of hematology and clinical biochemistry showed a treatment–time interaction. FumD application resulted in Sa/So ratios comparable to the control, indicating that the enzymatic treatment was effectively preventing the fumonisin-induced disruption of sphingolipid metabolism.

The association between infant and young child feeding practices and diarrhoea in Tanzanian children

BACKGROUND

Diarrhoea is a leading cause of child mortality in Tanzania. The association between optimal infant feeding practices and diarrhoea has been reported elsewhere, but the evidence has been limited to promote and advocate for strategic interventions in Tanzania. This study examined the association between infant and young child feeding (IYCF) practices and diarrhoea in Tanzanian children under 24 months.

METHODS

The study used the Tanzania Demographic and Health Survey data to estimate the prevalence of diarrhoea stratified by IYCF practices. Using multivariable logistic regression modelling that adjusted for confounding factors and cluster variability, the association between IYCF practices and diarrhoea among Tanzanian children was investigated.

RESULTS

Diarrhoea prevalence was lower in infants aged 0-5 months whose mothers engaged in exclusive breastfeeding (EBF) and predominant breastfeeding (PBF) compared to those who were not exclusively and predominantly breastfed. Infants aged 6-8 months who were introduced to complementary foods had a higher prevalence of diarrhoea compared to those who received no complementary foods, that is, infants who were exclusively breastfed at 6-8 months. Infants who were exclusively and predominantly breastfed were less likely to experience diarrhoea compared to those who were not exclusively and predominantly breastfed [adjusted odds ratio (AOR) 0.31, 95% confidence interval (CI) 0.16-0.59, P < 0.001 for EBF and AOR = 0.30, 95% CI 0.10-0.89, P = 0.031 for PBF]. In contrast, infants aged 6-8 months who were introduced to complementary foods were more likely to experience diarrhoea compared to those who received no complementary foods (AOR = 2.91, 95% CI 1.99-4.27, P < 0.001).

CONCLUSIONS

The study suggests that EBF and PBF were protective against diarrhoeal illness in Tanzanian children, while the introduction of complementary foods was associated with the onset of diarrhoea. Strengthening IYCF (facility- and community-based) programmes would help to improve feeding behaviours of Tanzanian women and reduce diarrhoea burden in children under 2 years.

Risk of Exposure to Multiple Mycotoxins from Maize-Based Complementary Foods in Tanzania

This study estimated exposure to multiple mycotoxins in 249 infants aged between 6 and 12 months in three agro-ecological zones of Tanzania. Maize-based complementary food intakes were estimated using two 24 h dietary recalls. Using @Risk software, probabilistic exposure assessment was conducted by modeling maize intake data (kg/kg body weight/day) with previously determined multiple mycotoxin (except for ochratoxin A (OTA) and zearalenone (ZEA), present in only a few samples) contamination data (μg/kg) in maize. Maize intakes ranged from 0.13 to 185 g/child/day (average = 59 ± 36 g/child/day). The estimated mean exposures were higher for aflatoxins (6-fold), fumonisins (3-fold), and deoxynivalenol (2-fold) than health-based guidance values of 0.017 ng/kg body weight/day, 2 μg/kg body weight/day, and 1 μg/kg body weight/day, respectively. The population at risk of exposures above the limits of health concern ranged from 12% for HT-2 toxin through 35% for deoxynivalenol to 100% for aflatoxins. The exposure varied among the agro-ecological zones. Strategies targeting multiple mycotoxins in maize are urgently needed to minimize exposures in Tanzania.

Reducing Postharvest Losses during Storage of Grain Crops to Strengthen Food Security in Developing Countries

While fulfilling the food demand of an increasing population remains a major global concern, more than one-third of food is lost or wasted in postharvest operations. Reducing the postharvest losses, especially in developing countries, could be a sustainable solution to increase food availability, reduce pressure on natural resources, eliminate hunger and improve farmers’ livelihoods. Cereal grains are the basis of staple food in most of the developing nations, and account for the maximum postharvest losses on a calorific basis among all agricultural commodities. As much as 50%–60% cereal grains can be lost during the storage stage due only to the lack of technical inefficiency. Use of scientific storage methods can reduce these losses to as low as 1%–2%. This paper provides a comprehensive literature review of the grain postharvest losses in developing countries, the status and causes of storage losses and discusses the technological interventions to reduce these losses. The basics of hermetic storage, various technology options, and their effectiveness on several crops in different localities are discussed in detail.

Mycotoxin exposure and infant and young child growth in Africa: what do we know?

INTRODUCTION

Infant and young child (IYC) growth impairment remains a public health problem in Africa partly because infants are exposed to staple foods (contaminated with mycotoxins) at an early age. Understanding the role of mycotoxins in IYC growth is vital, and this paper systematically reviews the available knowledge.

METHODS

Studies were searched and included if they provided information on African IYC mycotoxin exposure rates and/or growth. Studies were excluded if subjects were older than 15 years, if they were animal studies or focusing on other mycotoxins. Relevant search words were included in search strings. Eight reviews were identified and reference lists scrutinised for additional studies.

RESULTS

Ten studies were included; 8 focused on aflatoxin (AF), 2 on fumonisin (FB) and none on deoxynivalenol (DON) and zearalenone (ZEA). AF exposure prevalence reached 100% with levels at 40.4 pg/mg. AF was present in umbilical cords indicating that AF crosses the placenta. Maternal exposure levels were correlated with breast milk levels. The highest levels of serum AF (mean 32.8 pg/mg) were measured in Benin and Togo with 5.4% reaching levels higher than 200 pg/mg. At the end of weaning, children had similar prevalence and exposure levels as adults. RESULTS also indicated that infants with higher levels of maternal exposure had significantly lower height-for-age z-scores (HAZ scores), although there was no significant association between cord AF and infant HAZ scores or AF in cord blood and HAZ scores. Significantly higher mean maternal AF levels related to lower weight-for-age z-scores (WAZ scores) were reported, and infants with higher levels of maternal exposure had significantly lower WAZ scores that decreased over age. Cord AF levels had no effect on infant WAZ scores. One study investigated the association between FB and IYC growth and found that those with FB intakes greater than the provisional maximum tolerable daily intake were significantly shorter (1.3 cm) and lighter (328 g). No studies investigated the role of DON and ZEA.

CONCLUSION

A limited number of epidemiological studies have been conducted, and available research indicates extreme exposures to AF. There are strong associations between AF exposure and stunting and wasting. However, more epidemiological research is urgently needed to understand the role of FB, DON and ZEA in IYC growth.

The stunting syndrome in developing countries

Linear growth failure is the most common form of undernutrition globally. With an estimated 165 million children below 5 years of age affected, stunting has been identified as a major public health priority, and there are ambitious targets to reduce the prevalence of stunting by 40% between 2010 and 2025. We view this condition as a 'stunting syndrome' in which multiple pathological changes marked by linear growth retardation in early life are associated with increased morbidity and mortality, reduced physical, neurodevelopmental and economic capacity and an elevated risk of metabolic disease into adulthood. Stunting is a cyclical process because women who were themselves stunted in childhood tend to have stunted offspring, creating an intergenerational cycle of poverty and reduced human capital that is difficult to break. In this review, the mechanisms underlying linear growth failure at different ages are described, the short-, medium- and long-term consequences of stunting are discussed, and the evidence for windows of opportunity during the life cycle to target interventions at the stunting syndrome are evaluated.

Review of the inhibition of biological activities of food-related selected toxins by natural compounds

There is a need to develop food-compatible conditions to alter the structures of fungal, bacterial, and plant toxins, thus transforming toxins to nontoxic molecules. The term 'chemical genetics' has been used to describe this approach. This overview attempts to survey and consolidate the widely scattered literature on the inhibition by natural compounds and plant extracts of the biological (toxicological) activity of the following food-related toxins: aflatoxin B1, fumonisins, and ochratoxin A produced by fungi; cholera toxin produced by Vibrio cholerae bacteria; Shiga toxins produced by E. coli bacteria; staphylococcal enterotoxins produced by Staphylococcus aureus bacteria; ricin produced by seeds of the castor plant Ricinus communis; and the glycoalkaloid α-chaconine synthesized in potato tubers and leaves. The reduction of biological activity has been achieved by one or more of the following approaches: inhibition of the release of the toxin into the environment, especially food; an alteration of the structural integrity of the toxin molecules; changes in the optimum microenvironment, especially pH, for toxin activity; and protection against adverse effects of the toxins in cells, animals, and humans (chemoprevention). The results show that food-compatible and safe compounds with anti-toxin properties can be used to reduce the toxic potential of these toxins. Practical applications and research needs are suggested that may further facilitate reducing the toxic burden of the diet. Researchers are challenged to (a) apply the available methods without adversely affecting the nutritional quality, safety, and sensory attributes of animal feed and human food and (b) educate food producers and processors and the public about available approaches to mitigating the undesirable effects of natural toxins that may present in the diet.