REHIS Trainers' Seminar, October 2009 Mycotoxins and the food chain Kofi Aidoo Professor of Food safety, Glasgow Caledonian University

REHIS Trainers' Seminar, October 2009

Mycotoxins and the food chain

Kofi Aidoo

Professor of Food safety, Glasgow Caledonian University


Causes of food poisoning

• Bacteria or their toxins• Viruses• Chemicals• Poisonous plants (eg. deadly nightshade) and

fungi (poisonous mushrooms)• Natural toxicants - plants, fish, mycotoxins• Allergy - not the result of food being

contaminated.


Mycotoxins

• Mycotoxins - toxins produced by micro-fungi eg Aspergillus spp. (Macro-fungi, eg. mushrooms)

• Mycotoxins have 4 basic toxicity - acute, chronic, mutagenic, teratogenic.


Mycotoxins

• Toxigenic moulds - Aspergillus, Penicillium, Fusarium are found on human food and animal feed - animal products, eg meat or milk may become contaminated.

• Other toxigenic moulds may be present in the environment.


Fungal toxins

• Unlike bacterial toxins, fungal toxins (mycotoxins) are not proteins and therefore are not usually detectable by the immune systems of humans and animals


Symptoms of mycotoxicosis

• Symptoms are diverse• Some elicit few symptoms until

death• Severe effects include (a) skin

necrosis and b) immunosuppression


Mycotoxigenic filamentous fungi

• Rhizopus spp.• Byssochlamys spp.• Claviceps spp.• Eupenicillium spp.• Eurotium spp.• Neosartorya spp.• Talaromyces spp.• Alternaria spp.• Aspergillus spp.

• Penicillium spp.• Fusarium spp.• Cladosporium spp.• Geotrichum candidum• Paecilomyces variotii• Phomopsis spp.• Stachybotrys spp.• Trichoderma viride• Wallemia sebi


Types of mycotoxins

• There are over 300 mycotoxins but the commonly occurring ones in food and feed.

• About 20 mycotoxins occur in food at levels and frequency to be of food safety concern.


Mycotoxins associated with food and feed

• Aflatoxins (B1, B2, G1, G2, M1)

• Ochratoxin A• Zearalenone• Fumonisins• Trichothecenes• Patulin• Moniliform• Sterigmatocystin

• Citrinin• Cyclopiazonic acid• Kojic acid• Maltoryzine• ß-nitropropionic acid• Aspergillic acid• Penicillic acid• Roquefortine C


Mycotoxins and world food supply

• It is estimated that 25% of world’s food crops are affected annually by variable levels of mycotoxins.

• >100 countries have regulations regarding levels of mycotoxins in food and feed.


Principal toxigenic moulds and food crops

• Aspergillus ochraceus - cereals, nuts, pulses, oilseeds, corn….. ochratoxins, penicillic acid

• A. flavus or A. parasiticus - cereals, nuts, root crops, oilseeds, pulses….…aflatoxins

• Penicillium spp. - cereals, root crops, nuts, beans…………..ochratoxin, patulin, citrinin

• Fusarium spp. - cereals, root crops ….. T-2 toxins, zearalenone


Toxicological effects of AFLATOXINS

• the most toxic mycotoxin (in particular AFB1) • they are genotoxic carcinogens • they cause cancer and have been linked to

liver cancer in a number of developing countries

• not possible to determine threshold below which this toxin has no effect

• therefore No Tolerable Daily Intake has been recommended.


Aflatoxin M1

• Aflatoxin M1 is an oxidative metabolite of Aflatoxin B1.(ie produced from AFB1 in mammals)

• Aflatoxin M1 may be present in milk and dairy products.

• Aflatoxin M1 has been reported in human breast milk particularly in developing countries - Middle East, Africa, South Asia.


Toxicological effects of OCHRATOXIN A

• damages and causes cancer of the kidneys (shown in laboratory animals);

• has been associated with development of Balkan Endemic Nephropathy - a specific type of kidney disease in certain human population;

• EU have set a TDI of <5 ng/kg per kg body wt per day (kg/bw/d)


Toxicological effects of PATULIN

• exhibits strong antibiotic activity against bacteria;

• causes haemorrhage, oedema and dilation of the intestinal tract of experimental animals

• EU have endorsed a provisional maximum TDI of 0.4 µg/kg bw/d


Toxicological effects of FUSARIAL TOXINS

• Fumonisins cause kidney and liver damage; oesophageal cancer; TDI of 2µg/kg bw/d

• Trichothecenes (DON, T-2, HT-2 toxins) causes growth retardation, reproductive and intestinal effects, also affects immune systems; a group TDI of 1 µg/kg.

• Zearalenone has oestrogenic effects. A possible incidence of precocious puberty associated with zearalenone in Hungary; EU TDI of 0.2 µg/kg bw/d.


Human mycotoxicosis

In 1967, 26 Taiwanese in a farmingcommunity became ill after eatingcontaminated rice; 3 children died.

Cause of death: Contaminated rice showed >200 µg aflatoxin B1/kg.


Human mycotoxicosis

In 1974, an outbreak of hepatitis in Indiaaffected 400 people resulting in 100deaths;

Cause of death: aflatoxins in corn ( >15mg/kg)


Human mycotoxicosis

In 2004, one of the largest aflatoxicosisoutbreak occurred in rural Kenya resultingin 317 cases and 125 deaths.

Cause of death: corn contaminated with4,400 µg/kg of aflatoxin B1, 220 timeshigher than Kenyan regulatory limit forfood.


Mycotoxins and EU Regulation 1881/2006

Mycotoxin Fruits, etc

Cereals, etc

Milk, etc Coffee, wine

Nuts, spices

Baby food

Aflatoxins

B1B2G1G2

Aflatoxin M1 Trichothecenes (DON, T2 toxins) Zearalenone OTA Patulin


EC Legislative limits of mycotoxins in food and feedstuffs (EC 1881/2006)

• AflatoxinsAflatoxins in oilseed 2 ppb AFB1 (µg/kg) & 4 ppb total aflatoxin; 8 & 15 ppb respectively for oilseeds for further processing.

• For almonds, hazelnuts, pistachios for direct human consumption 5 ppb for AFB1 & 10 ppb for total.

• AflatoxinsAflatoxins B1 & M1 in baby milk/food < 0.1 & 0.05 ppb respectively.

• OTA - OTA - 10 ppb in dried vine fruits & soluble coffee; 5 ppb for roasted coffee; 6-10 ppb for instant coffee; 2 ppb for wine and grape juice; 0.2 ppb for beer

• OTAOTA - 15-30 ppb in spices applicable from 1 July 2010


EC Legislative limits of Fusarium toxins in food

• DONDON - 500µg/kg in cereal based products and 100µg/kg for cereal based products in baby food

• T-2T-2 and HT-2 toxinsHT-2 toxins - 200µg/kg in cereal based products and 50µg/kg for cereal based products in baby food.

• ZearalenoneZearalenone - 50µg/kg in cereal based products and 20µg/kg for cereal based products in baby food.

• FumonisinsFumonisins - 500µg/kg in corn based products; 200µg/kg in cornflakes and 100µg/kg in baby food


FSA’s strategy on mycotoxins

Divided into 3 major themes: • (i) maintain current awareness of levels of

mycotoxin contamination of foods in general, • (ii) identify factors contributing to occurrence

of mycotoxins and thereby provide information necessary to manage the risk of mycotoxin formation and

• (iii) provide stakeholders with advice/tools on how best to manage the problem of mycotoxin contamination.


Potential uses of mycotoxins

• Medical application - Trichothecenes are known to possess antileukaemic activity; zearalenone derivatives have been considered as potential treatment for menopausal syndrome in women;

• Agriculture application - derivatives of zearalenone as growth promoter in sheep and cattle; other mycotoxins have been considered for use as herbicides and insecticides.


Websites• UK Food Standards Agency,2002. Survey of nuts, nut products and dried tree fruits for

mycotoxins. Food Survey Information Sheet 21/02 • http://www.food.gov.uk/science/surveillance/fsis2002/21nuts • UK Food Standards Agency, 2004. Survey of baby foods for mycotoxins,• Food Survey Information Sheet 68/04.• http://www.food.gov.uk/science/surveillance/fsis2004branch/fsis6804• UK Food Standards Agency, 2005. Survey of wheat for ochratoxin A, Food Survey Information

Sheet 77/05.• http://www.food.gov.uk/science/surveillance/fsis2005/fsis7705 • UK Food Standards Agency, 2005. Survey of spices for aflatoxins and ochratoxin A, Food Survey

Information Sheet 73/05.• http://www.food.gov.uk/science/surveillance/fsis2005/fsis7305 • UK Food Standards Agency, 2005. Survey of maize-based retail products for mycotoxins, Food

Survey Information Sheet 72/05• http://www.food.gov.uk/science/surveillance/fsis2005/fsis7204 • UK Food Standards Agency (FSA) 2009a. Review of Programmes C03 & C04 (Mycotoxins and

Nitrate). Final Report. 48pp.• UK Food Standards Agency (FSA) 2009. Food Contaminants. Update Bulletin, March.

www.food.gov.uk•

Documents

REHIS Trainers' Seminar, October 2009 Mycotoxins and the food chain Kofi Aidoo Professor of Food safety, Glasgow Caledonian University