ARE you daily consuming low amounts of toxins (poison or contaminants) in your diet? This question looks weird, but there is always a hidden meaning in this type of queries! At least, once in our lives, majority of us might have eaten spoilt groundnuts, other nuts, or spoilt fruits or vegetables knowingly or unknowingly!
It is an established fact that eating spoilt foods can lead to stomach ache, vomiting or diarrhoea and in worst cases onset of fever. Consulting a doctor, it is usually a case of food poisoning. Well, the real culprit behind food poisoning are a group of micro-organisms; usually a bacteria or fungi. Bacterial food poisoning has been well documented and consumers are aware of this. However, the majority of consumers might not be aware on fungal toxins or the mycotoxins produced (as low molecular weight secondary metabolites) by fungi or moulds which can seriously affect our health (in Greek mykos means fungus and toxikon means poison). Of course, most of us are familiar with fungi growing on old bread (as black/grey mat-like mouldy growth), on spoilt oranges, apple or pear (as blue green moulds), etc.
Symptoms of
mycotoxins poisoning
The general symptoms of mycotoxicosis; referring to illness/disease caused by ingestion of mycotoxins via food includes vomiting, diarrhoea, abdominal cramps, and other gastro-intestinal problems. In general, regular intake (unknowingly) of mycotoxins contaminated food can suppress the immune system in humans leading to cancer of the lungs, oesophagus etc, hormonal imbalance and inducing feminising syndrome in men.
In animals (livestock or poultry), mycotoxins intake via contaminated feed can result in the reduction of animal productivity, increased diseases because of immunity-suppression, damage to vital organs (including reproduction organs), and in extreme cases death.
Food contamination
Some of the common agri-food commodities in which mycotoxins have been detected include rice, wheat, corn, maize, peanuts, spices, cheese and fresh milk.
Fungal species such as aspergillus, penicillium, fusarium, paecilomyces, byssochlamys sp and others invade food crops in elds, grow luxuriantly during storage and produce the deadly mycotoxins with favourable environmental conditions; temperature, moisture or relative humidity). Mycotoxin-producing fungi can survive in almost all environmental conditions ranging from Artic or Antarctic regions up to the hottest part of a dessert.
Practice of poor harvesting principles, inefficient drying, packaging, storage, handling and transport conditions contributes tremendously to fungal contamination and risks of producing mycotoxins in food and feed.
Historically, death caused by ergotism (St Anthony’s firre or firre sickness) is stated in the Old Testament. If a person experiencing an intense burning sensation was sent on a pilgrimage to the shrine of St Anthony, then a relief was experienced.
Even the decline in the Etruscan civilisation has been attributed to mycotoxins (fusarial toxins). Also, Egyptian tombs were discovered to contain mycotoxins (ochratoxin A), thought to be responsible for mysterious death of numerous archaeologists.
In the 1960s, a hundred thousand turkey birds had died because of mycotoxin (aflatoxins) poisoning in the UK. During 1972 to 1988 outbreaks of food poisoning because of “mouldy sugarcane poisoning” was reported.
There are also reports of pure mycotoxins being used for biological weapons during 1980s cold war era.
Types of mycotoxins
As of today, more than 400 different types of mycotoxins have been isolated from various agri-food commodities. However, the most significant mycotoxins affecting humans includes; aflatoxins, ochratoxin, fumonisins, patulin and citrinin.
Aflatoxins (B1, B2, G1, G2, M1) are extremely toxic, carcinogenic and mutagenic compounds (linked with onset of liver cancer). They have been isolated from cereals (maize, rice), spices (black pepper, chillies, ginger, turmeric), oilseeds and their edible oil (olive, peanuts, sunower), tree nuts (almond, pistachio), milk, raw drugs, etc. Aflatoxin M1 was also found in breast milk, cord-blood and maternal blood. Aflatoxin occurrence is common where warm/ humid conditions are prevalent.
Ochratoxin-A (OTA) is nephrotoxic, immuno-suppressive, carcinogenic and a teratogenic compound mainly found in coffee, cocoa, wine, dried fruit and dried spices. OTA has been detected in internal organs (mainly in kidneys) of animals fed on contaminated feeds. The IARC (International Agency for Research on Cancer) has classified OTA as group 2B carcinogen to humans (mainly causing kidney cancer). OTA is also related to occurrence of endemic nephropathy and urothelial tumors.
Fumonisin toxins are carcinogenic compounds (mainly causing oesophageal cancer). These are usually found contaminating maize, corn flour, maize, dried figs, herbal tea, etc. Consumption of fumonisin contaminated foods is related to neural tube defects in babies. Fumonisins are immune-suppressive, and IARC has classified them as group 2B human carcinogen.
Patulin toxins interferes with normal functioning of kidney, liver, gastro-intestinal tissues, and interrupts basic immune system. This toxin is categorised to be carcinogenic and genotoxic, and contributes to apoptosis of human leukemia cells. Patulin toxins have been detected in fungal contaminated fruits and vegetables, and are considered to be the most hazardous mycotoxins in apple, pears, and their respective products.
Citrinin has been detected in barley, maize, fruits, dietary supplements and feed. Barley (used in beer production) is reported to support the growth of fungi capable of producing citrinin. Reported health risks in humans are scarce. There are reports linking citrinin with occurrence of Balkan endemic nephropathy in humans and mycotoxic nephropathy in swine. Citrinin is also reported to be nephrotoxic and teratogenic in rabbit, poultry and dogs.
Safety limits, treatment
for mycotoxin ingestion
The daily regulatory/safe limit set for mycotoxins in food varies in different countries and for adults and children. For example, as per the regulation of the European Union (directive 2006/125/141/EC), maximum levels of intake (among infants and young children) for aflatoxin B1 is 0.10; aflatoxin M1 is 0.025; ochratoxin A is 0.5; fumonisins is 200; and patulin: 10 (all in micrograms per kilograms). However, as per the Food and Agriculture Organisation (FAO), daily permissible limits for adults for aflatoxins (B1) is 5; fumonisins is less than 1; patulin (in apple juice) 50 (all in micrograms per kilograms), and for OTA it is set at 120 nano gram per kilogram.
Though there is no antidote for mycotoxins poisoning, the usual recommendations includes: opting for regular cleansing of liver and digestive tracts, use of more probiotics in diet, taking more vitamin B and selenium supplements, improving immunity system, opting grain-free diet, consuming healthy foods, etc.
Use of activated charcoal during suspected mycotoxin poisoning is also recommended.
As prevention is always better than cure, consumers are advised to discard suspected contaminated foodstuff and consume only healthy foods.
Prevention of mycotoxins
Inhibition of fungal contamination and mycotoxins production in crops can be achieved either during pre-harvest stages (by adopting good agricultural practices) or during post-harvest stages (by adopting good hygienic and handling practices). Application of safe or natural fungicides can reduce fungal growth at all the levels.
As Fiji’s weather (hot and humid) can support fungal growth and production of mycotoxins, it is highly important that local farmers are trained to adopt appropriate measures to overcome contamination at the farm, storage or transportation levels.
Awareness needs to be created among local consumers on the ill-effects of consuming contaminated food commodities. Finally, not to forget the old saying: “To eat is a necessity, but to eat intelligently is an art” and hence it is vital that consumers practice a healthy eating and healthy lifestyle.
* Dr Rajeev Bhat is working as associate professor and the head of FNU’s Food Science Department. Views expressed are his and not of this newspaper or his employer. For queries, email: rajeev.bhat@fnu.ac.fj or hodfs@fnu.ac.fj.
