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The sources of toxic compounds in our food ? Man-made (anthropogenic) Natural origin Food additives Toxins of vegetable origin Food contaminants Toxins.

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Presentation on theme: "The sources of toxic compounds in our food ? Man-made (anthropogenic) Natural origin Food additives Toxins of vegetable origin Food contaminants Toxins."— Presentation transcript:

1 The sources of toxic compounds in our food ? Man-made (anthropogenic) Natural origin Food additives Toxins of vegetable origin Food contaminants Toxins in mushrooms - inorganic - inorganicMycotoxins - organic - organic Microbial toxins Component produced during the technological and cooking procedures Toxins of animal origin Products of interactions in human body

2 Chemical changes during food processing AgricultureAgriculture Food industryFood industry CateringCatering Cooking in householdsCooking in households Other techniques in householdsOther techniques in households

3 Mycotoxins – toxic products of moulds Humidity, warmth, damage of corns due to crop techniques Harvesting of cerealsHarvesting of cereals Storage of cerealsStorage of cereals Storage and package of cereal products (bread packed in PE)Storage and package of cereal products (bread packed in PE) Fruits, compote, beer (malt)Fruits, compote, beer (malt) Nuts, peanuts, coffee, cocoaNuts, peanuts, coffee, cocoa Mouldy fodder (animal)Mouldy fodder (animal) Metabolites of mycotoxins in milkMetabolites of mycotoxins in milk

4 Toxic effects of mycotoxins Genotoxic and carcinogenic: aflatoxins, ochratoxins, fumonisins, griseofulvin, trichotecens aflatoxins, ochratoxins, fumonisins, griseofulvin, trichotecens Hepatotoxic: aflatoxins, luteoscyrin, sterigmatocystin Estrogenic: zearalenon Nefrotoxic: ochratoxin, citrinin Dermatotoxic: trichotecens, psoralens, sporidesmins, verrukarins Hematotoxic: aflatoxins, ochratoxin A, trichotecens, zearalenon Immunotoxic: aflatoxins, ochratoxin A, trichotecens, patulin, sporidesmin

5 Diseases associated with mycotoxins Aflatoxins Aflatoxicosis, kwashiorkor, Reyes syndrom, primary hepatocarcinoma (synergism with HBvirus) Ochratoxin A Balkan endemic nefropathy, kidney tumors Trichotecens Alimentar toxic aleukia, stachybotriotoxicosis Fumonisins Oesophageal tumors Citreoviridin Citrinin, Luteoscyrin Acute cardiac beri-beri, yellow rice disease Ergot alcaloids (Toxic products of Claviceps purpurea) ergotism

6 Aflatoxin B1 Primary hepatocarcinoma – metabolic activation

7 Prevention of mycotoxins Proper handling food commodities prone to contamination with fungies Not eat mouldy food Not used the mouldy food as fodder for domestic animals Proper control of food products (mostly nuts), especially before Christmas

8 Toxic products of bacteria Biogenic amines Histidine in fish meat – bacterial decarboxylases - histamine Tyrosine in cheese - bacterial decarboxylases – tyramine (increase of blood pressure in case of combination with MAO inhibitors) Bacterial toxicoinfection a toxicoses: staphyfylococcus enterotoxicosis, botulotoxin, intoxication with Clostridium. perfringens A, Bacillus cereus Bacterial reduction of nitrates to nitrites: methemoglobinemia, nitrosamines Lipolytic and proteolytic effects of microorganisms

9 Nitrosamines Nitrates Nitrites Methemoglobinaemia of infants (+ amines) Nitrosamines Bacterial reductases + acidic pH Vit. C, E Smoked meat: mixture of nitrate and nitrite salts

10 Uncommon toxicants originated due to food- processing technology Chlorpropandiols (3-MCPD) Production of soup spice, soy sauce, products containing protein hydrolysates Acid digestion (HCl) – cleavage of fatty acids – binding of chlorine = increased biologic activity of chlorine derivatives (mutagenicity). Enzymatic hydrolysis is more expensive but safe Acrylamide Formation during the production of chips, bread, cakes etc. The amount depends somehow on the technology used Potential carcinogen (Hb adducts), neurological changes

11 Acrylamide Product of Maillard reaction The Maillard reaction is a form of nonenzymatic browning. It results from a chemical reaction between an amino acid and a reducing sugar, usually requiring heat. It can be formed in starchy foods during cooking. Formation during the production of chips, bread, cakes etc. The amount depends somehow on the technology used Potential carcinogen (Hb adducts), neurological changesPotential carcinogen (Hb adducts), neurological changes

12 Culinary technologies Frying : Changes in frying oil = changes in frying foods Chemical reaction during frying: 1. Hydrolysis due to water vapour released from frying food. Acrolein, originated in final phase, is irritating agents for eyes and mucous tissues. 2. Oxidative reactions – especially in longer used oils, where the presence of polar compounds facilitates foaming. 3. Formation of hydroperoxides – oxidation of mono-ene and saturated fatty acids 4. Cumulating of polymers in frying oil

13 Adverse consequences of frying: Increased oxidation stress (carcinogenicity, degenerative diseases, premature aging) Loss of unsaturated FA Oxidation of blood lipids, namely LDL cholesterol, Oxidative products cumulated in macrophages constitute a basis of atherosclerotic plate in walls of blood vessels. Lipid peroxidation generates a complex variety of products; some of them react with proteins and DNA (damage of DNA, genotoxicity, carcinogenicity Chemoprevention by means of antioxidants in fruits, vegetables, green tea etc.

14 Adverse consequences of frying: Increased intake of fat (increased risk of cancer) Food with a high content of water (e.g. potatoes, mushrooms, vegetables) absorbs a lot of fat during the frying process, because the water in poruses is evaporating and the free places are filled with fat.

15 Adverse consequences of frying: High temperature decomposes ascorbic acid, vitamin E, carotenes and other vitamins (loss of vitamins) Also the content of some minerals and trace elements (e.g. selenium) can change Non-enzymatic browning of amino acids with reducing sugars or with oxidative products in frying oil. Nitrogen products are generating such as pyrrols, pyrrazines, furans (Maillard reaction). Disbalance of amino acids and a worsening of protein quality Loss of unsaturated FA (PUFA) Production of polycyclic aromatic hydrocarbons Production of heterocyclic amines

16 Heterocyclic amines (HA, protein pyrolysates) Generated in the meat dishes during the cooking process due to reaction of amino acids (e.g. glycin, phenylalanine), creatine, creatinine, and sugar (glucose) in meat in high temperature. The amount of HA depends on the height of temperature and the duration of cooking procedure Hamburger, beef, fish, bouillon

17 More than 20 HAs have been isolated from cooked food Extremely potent indirect-acting mutagens in short-term tests on mutagenicity (induction of mutation of bacterial tester strains, DNA adducts formation, chromosomal changes) HAs are activated by means of CYP1A2 (cytochrome P450) Detoxification: hydroxylation, conjugation Some of HA are carcinogenic for animals, but HAs are not strong carcinogens Possibly carcinogenic for humans – association with Ca colon and rectum Heterocyclic amines (cont.)

18 Factors affecting the yield of HAs in cooked food: Cooking temperature (more above 200°C) – well done grilled, pan-fried or barbecue red meat Cooking time (transport of HAs from the meat to the pan residue) Cooking method (no HAs in microwave warming) Type of food (content of precursors and inhibitors)

19 Heterocyclic amines (prevention) Use cooking, stewing, prevent meat from open fire, use microwave, remove roasted part of meat Reduce the resorption of HA in organism (crude fibres, vegetable, chlorophyll) Blockade of metabolic activation to carcinogenic intermediates (catechines in green tea, onion, cruciferous vegetable, allylsulfids in garlic, carotenoids Some heterocyclic amines are also present in cigarette smoke!!!

20 Heterocyclic amines (prevention) Universal recommendation The formation of HAs is minimized if the cooking temperature is kept low and constants (below 200°C) Consume the meat always with a lot of vegetables and fruit Drink a glass of (red) wine to the meal

21 Polycyclic aromatic hydrocarbons (PAHs) Production: incomplete combustion of organic compounds (including foods such as smoked products, grilled, fried, baked meat, barbecue etc.) The use of open fire contribute mostly to the generation of PAHs in food. Food containing PAHs are especially: Fried, roasted, grilled meat and smoked sausage Smoked meat and fish Fried chips Roasted coffee sedimentation of air particles containing PAH on leafy vegetables

22 Cooling and freezing of food Reason: To avoid of the loss of vitamins and other micronutrients The importance of refrigerators in prevention of stomach cancer Shocked freezing (during the slow freezing the small ice crystal in meat destroy the cells and let the fluids escape – loss of vitamins and minerals Cooling of poultry with running water increases the risk of contamination with Campylobacter jejuni. Notice: moulds can grow even in the temperature slightly above zero, i.e. in refrigerator

23 Drying Increases the level of heavy metals contaminated vegetable, herbs, herb-teas etc. (Cd, Pb)

24 Insufficient termal procedures Increased risk of infectious: Bacterial (salmoneloses) Intoxication (botulotoxin, staphyllococci enterotoxicosis) Viruses (Hepatitis A) Parazites (taeniae, trichinellosis)

25 Trans fatty acids Unsaturated fatty acids with at least one double bond in a trans configuration in the molecule Intake: ruminant meat, fat, milk fat, butter Hardened fats are the main exposure source (hydrogenation of vegetable oil to hardened fat – margarine- products) One of risk factors of the ischemic heart disease TFA increase the plasma ratio of total to HDL cholesterol Estimated about 7% of coronary artery disease to be attributable to TFA

26 GMO and food production Improvement of agronomic charactristics Tolerance to herbicides: - Induction of gene coding the enzyme for resistance to herbicides (e.g. Tolerance to glyphosphate – Roundup Ready or to glucosinate - BASTA). - Induction of gene coding the enzyme detoxifying herbicide Pros.: increase of production, decrease of costs Contr: lowering of biodiversity, creation of „superweeds“? Resistence to insects - Endotoxin from B. thuringiensis (Bt-maize, cotton-plant) Advantage: reduction of amount of chemical pesticides, lowering of mycotoxins, protection of beneficial insect

27 GMO and food production (cont.) Resistance to viruses, bacteria and fungies Increased tolerance to abiotic stress (dryness, salinity) Increase of iron bioavailability

28 GMO and food production Improvement of nutritional characteristics Modification of fatty acids, optimalization of lipid spectrum in edible oils, Improvement of quality of protein in food and feeds (increased amounts of essential aminoacids, e.g. methionine in soya), Improvement of biosynthesis of starch, Biosynthesis of  -carotene (Golden rice) – prevention of vitamin A deficiency in Southwest Asia, Synthesis of  -tocoferol (  -tocoferol metyltransferase from Arabidopsis), Increased amount of iron in rice (gene for ferritin from Phaseolus vulg., or for termoresistent fytase from Aspergillus fumigatus or increased expression of protein metalothionein)

29 GMO and food production Improvement of sensoric characteristics and storability: FLAVR SAVR TM tomatoes with prolonged time of ripening – inhibition of polygalakturase, key enzyme for softening of cell walls. Changes of technology: Production of chymosine by means of GM microorganisms (earlier from calf stomach)

30 GMO and food production Production of farmaceuticals (vaccines, insulin); Introduction od vaccines into the ordinary used food (e.g. vaccine against HBV or diarrhea diseases into bananas or potatoes; not yet realized GMO and commerce Prolongation of lifetime of cut flowers; Changes of color (production of blue cotton), wood lignin (furniture industry);

31 Further potential GMO utilisation Production of human proteins (factors VIII and IX for the therapy of hemofilia, alfa-1-antitrypsin for the therapy of emphyseme, antitrombin for prevention of trombosis) Increased growth of domestic animals (livestock) (e.g. transport of gene for growth factor to salmon) Increased resistance to animal diseases (leucosis in poultry, BSE,, skrapie in sheep, H5N1 in poultry)

32 Potential health and environmental risks of GMO? Resistance to ATB Toxicity Alergenicity Worsening of biodiversity Cross-pollination between GMO and non-GMO plants Polyresistance to herbicides Contamination of honey with pollen from GMO plants (not known adverse effect yet) Other??????? Prevention: legislation, health risk assessment

33 Message to take with Efficient prevention of moulds Use of moderate cooking temperature Limit the use of grilling, BBQ and other techniques using high temperatute and open fire Limit the consumption of cakes containing margarines with high concentration of trans fatty acids

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