Aflatoxin and Kwashiorkor

The aetiology and pathogenesis of kwashiorkor remains obscure. Clinical and epidemiological studies are in progress in Sudan to determine whether aflatoxins play a role in the pathogenesis of kwashiorkor. Local foods are screened for their aflatoxin content and children with kwashiorkor and age and sex matched children with marasmus and with normal nutrition are being investigated for aflatoxins in their blood and urine. Autopsy liver samples of children with kwashiorkor and other nutritional disorders in Nigeria and South Africa have been examined for their aflatoxin content. Aflatoxins are detected using two dimensional thin layer chromatography and high performance liquid chromatography. Results to date on over 350 children studied show that aflatoxins occur more frequently and at higher concentrations in the sera of children with kwashiorkor than in children with marasmus or in normal children. Urinary excretion of aflatoxins in kwashiorkor appears to be less than in other groups. In the autopsy liver samples, aflatoxins have been detected in all kwashiorkor livers but not in livers from marasmic children. These findings seem to implicate aflatoxins in the pathogenesis of kwashiorkor. If this is confirmed it would have very wide implications for the management and prevention of kwashiorkor.




Aflatoxins and kwashiorkor. Epidemiology and clinical studies in Sudanese children and findings in autopsy liver samples from Nigeria and South Africa.(http://www.ncbi.nlm.nih.gov/pubmed/6673848?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed)

some more information on analytical identification of aflatoxins

Solid-Phase Extraction
All analytical procedures include three steps: extraction, purification, and determination. The most significant recent improvement in the purification step is the use of solid-phase extraction.
Test extracts are cleaned up before instrumental analysis (thin layer or liquid chromatography) to remove coextracted materials that often interfere with the determination of target analytes.

High-pressure Liquid Chromatograph
High-pressure Liquid Chromatography (HPLC) is widely used as a separation technique in aflatoxin analysis to separate, identify, and quantify compounds. It includes analyte application, stationary phase, and mobile phase.
Liquid chromatography methods for the determination of aflatoxins in foods include normal-phase LC (NPLC), reversed-phase LC (RPLC) with pre- or before-column derivatization (BCD), RPLC followed by postcolumn derivatization (PCD), and RPLC with electrochemical detection.

Immunochemical Methods
HPLC methods for determining aflatoxins in food are laborious and time consuming. These techniques often require knowledge and experience of chromatographic techniques to solve sepatation and and interference problems. Through advances in biotechnology, highly specific antibody-based tests are now commercially available that can identify and measure aflatoxins in food in less than 10 minutes. These tests are based on the affinities of the monoclonal or polyclonal antibodies for aflatoxins. The three types of immunochemical methods are radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISA), and immunoaffinity column assay (ICA).





http://www.fs-pt.com/analytical_laboratory_services/aflatoxin_aspergillus_analysis.html

More on alflatoxin toxicity

Aflatoxin affects liver causing cirrhosis, hepatoma, hepatitis, and Rey's disease as, well as affect other organs like kidney, myocardium, and muscles. Even it may lead to decreased immunity in animal. A study conducted among the Philippine people with liver cancer showed 440% higher consumption of aflatoxin as compared to controls.

Time to time there has been outbreaks of aflatoxin toxicity caused by the consumption of moldy grain. A recent outbreak of jaundice due to aflatoxin toxicity occurred in Kenya. The mortality rate was as high as 39%. The problem is more in this part of the world where there is no proper place to keep the grains dry for long time. It is very difficult to keep all foodstuff in airtight containers. In an outbreak, 106 people died and 291 showed symptoms of hepatic dysfunction after consumption of moldy maize. Although liver, kidney, and muscles are commonly affected by aflatoxin, the brain is also affected. Autopsy of Thai children who died due to encephalopathy showed aflatoxin in their specimen. There are reports of the presence of aflatoxin in the blood of people from Nepal, who consumed contaminated food and feed. In a study, more than 11% children with kwashiorkor showed aflatoxin in their blood as compared to none of the controls. It has been shown that the birth weight of the baby is also affected if mothers have taken aflatoxin in their food during pregnancy. A strong negative correlation between aflatoxin and birth weight has also been observed.

Aflatoxin not only gives rise to cases of poisoning but is also associated with cancer (liver), kwashiorkor, and growth retardation among children.




http://www.indianjmedsci.org/article.asp?issn=0019-5359;year=2005;volume=59;issue=8;spage=331;epage=336;aulast=Koirala

Aflatoxins analysis

1.Initial assays will involve detection by HPLC, with confirmation by LC-MS. In countries where mycotoxins have been monitored in baby food, the methods used frequently involved immunoaffinity columns cleanup and HPLC or MS quantitation.


High-performance liquid chromatography (or High pressure liquid chromatography, HPLC) is a form of column chromatography used frequently in biochemistry and analytical chemistry to separate, identify, and quantify compounds. HPLC utilizes a column that holds chromatographic packing material (stationary phase), a pump that moves the mobile phase(s) through the column, and a detector that shows the retention times of the molecules. Retention time varies depending on the interactions between the stationary phase, molecules being analyzed, and the solvent(s) used.

Liquid chromatography-mass spectrometry (LC-MS) is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography (aka HPLC) with the mass analysis capabilities of mass spectrometry. LC-MS is a powerful technique used for many applications which has very high sensitivity and specificity. Generally its application is oriented towards the specific detection and potential identification of chemicals in the presence of other chemicals (in a complex mixture).

2. Detection and estimation for aflatoxin were done by using the thin layer chromatography method (TLC). Thin layer chromatography method is one of the commonest and widely used techniques to detect different types of food contaminants. Comparison of toxicity levels for aflatoxin was done by comparing fluorescence of sample spot with fluorescence of standard.

Thin-Layer Chromatography :
Thin layer chromatography (TLC) , also known as flat bed chromatography or planar chromatography is one of the most widely used separation techniques in aflatoxin analysis. Since 1990, it has been considered the AOAC official method and the method of choice to identify and quantitate aflatoxins at levels as low as 1 ng/g. The TLC method is also used to verify findings by newer, more rapid techniques .

http://www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=410262
http://en.wikipedia.org/wiki/LC/MS
http://en.wikipedia.org/wiki/HPLC
http://www.ansci.cornell.edu/plants/toxicagents/aflatoxin/aflatoxin.html

Health implications of alflatoxin

Human exposure to aflatoxin is through ingestion of contaminated foods. Inhalation of the toxins may also occur occasionally due to the occupational exposure.

Symptoms of acute toxicity: vomiting, abdominal pain, pulmonary edema, convulsions, jaundice, coma, and death with cerebral edema and fatty involvement of the liver , kidneys , and heart. Long term intake of aflatoxin can be associated with hepatic cancer.

Adult humans usually have a high tolerance of aflatoxin, and, in the reported acute poisonings, it is usually the children who die

For humans, aflatoxin is predominantly perceived as an agent promoting liver cancers, although lung cancer is also a risk among workers handling contaminated grain

http://www.fehd.gov.hk/safefood/report/aflatoxin/text_report.html
http://www.ajcn.org/cgi/content/full/80/5/1106

Aflatoxin

Aflatoxin is the secondary metabolite produced by specific strains of Aspergillus, Aspergillus flavus and Aspergillus parasiticus. These species contaminate various agricultural commodities either before harvest or at post-harvest stages under favourable conditions of temperature and humidity.Aspergillus is a large genus of mould which grows at an optimal range of temperature of 28-33°C and at the water activity of about 0.83-0.97. The aflatoxigenic moulds, namely A flavus, A parasiticus and A nomius are principally found in soils and decaying vegetation. They occur in warmer parts of the world such as tropical region where temperature and moisture are high. They have a higher affinity of growth in nuts and oilseeds.

Characteristics of Aflatoxin

• Aflatoxin is classified into a number of subtypes. However, the most important ones are B1, B2, G1 and G2, distinguished by their fluorescenct colour under ultraviolet light. In addition, aflatoxin, M1 and M2 are hydroxylated metabolites of aflatoxin B1 and B2.
  
• Unlike Aspergillus, which often look greenish to the naked eyes, aflatoxins are odourless, tasteless and colourless. Chemically, they are stable in foods and resistant to degradation under normal cooking procedures. It is difficult to eliminate aflatoxin once it is produced.
  
• Accumulation of aflatoxin is dependent upon weather conditions. Before harvest, the risk for the development of aflatoxin is greatest during major droughts. When soil moisture is below normal and temperatures are high, the number of Aspergillus spores in the air increases. These spores infect crops through areas of damage caused by insects, and inclement weather. Once infected, plant stress occurs, the production of aflatoxin is favoured.
  
• During post-harvest stage, proliferation of aflatoxin can be exacerbated in susceptible commodities under storage conditions such as hot and humid storage environment.

http://www.fehd.gov.hk/safefood/report/aflatoxin/text_report.html

pH of peanut butter

I've found one that say the pH of peanut butter is 6.28.

http://www.cfsan.fda.gov/~comm/lacf-phs.html