The sources of The sources of toxic toxic compounds in compounds in our our food food ? ? Man-made Man-made (anthropogenic) (anthropogenic) Natural origin Natural origin Food additives Food additives Toxins of vegetable Toxins of vegetable origin origin Food contaminants Food contaminants Toxins in mushrooms Toxins in mushrooms - inorganic - inorganic Mycotoxins Mycotoxins - organic - organic Microbial toxins Microbial toxins Component produced Component produced during the during the technological and technological and cooking procedures cooking procedures Toxins of animal Toxins of animal origin origin
Transcript
The sources ofThe sources of toxic toxic compounds incompounds in our our foodfood??Man-made Man-made
Component produced Component produced during the technological during the technological and cooking proceduresand cooking procedures
Toxins of animal originToxins of animal origin
Products of interactions Products of interactions in human bodyin human body
Chemical changes during food Chemical changes during food
processingprocessing • AgricultureAgriculture• Food industryFood industry• Catering Catering • Cooking in householdsCooking in households• Other techniques in householdsOther techniques in households
Humidity, warmth, damage of corns due to Humidity, warmth, damage of corns due to crop techniquescrop techniques
• Harvesting of cerealsHarvesting of cereals• Storage of cereals Storage of cereals • Storage and package of cereal productsStorage and package of cereal products
(bread packed in PE)(bread packed in PE) • Fruits, compoteFruits, compote, beer (malt), beer (malt)• Nuts, peanuts, coffee, cocoaNuts, peanuts, coffee, cocoa• Mouldy fodder (animal)Mouldy fodder (animal)• Metabolites of mycotoxins in milkMetabolites of mycotoxins in milk
Toxic effects of mycotoxinsToxic effects of mycotoxins
Genotoxic and carcinogenic:Genotoxic and carcinogenic:
aaflatoxinflatoxinss, ochratoxin, ochratoxinss, fumonisin, fumonisinss, griseofulvin, trichotecen, griseofulvin, trichotecens s
Hepatotoxic:Hepatotoxic: a aflatoxinflatoxinss, luteos, luteosccyrin, sterigmatocystinyrin, sterigmatocystin
Proper handling food commodities prone to contamination with fungies
Not eat mouldy foodNot used the mouldy food as fodder for domestic
animalsProper control of food products (mostly nuts),
especially before Christmas
Toxic products of bacteriaToxic products of bacteria
Biogenic aminesBiogenic amines
HistidineHistidine in fish meat – bacterial decarboxylases - in fish meat – bacterial decarboxylases - histaminehistamine
TyrosineTyrosine in cheese - bacterial decarboxylases – in cheese - bacterial decarboxylases – tyraminetyramine (increase of blood pressure in case of (increase of blood pressure in case of combination with MAO inhibitors)combination with MAO inhibitors)
BaBaccterial toxicoinfection a toxicoses: staphyfylococcus terial toxicoinfection a toxicoses: staphyfylococcus enterotoxicosis, botulotoxin , intoxication with enterotoxicosis, botulotoxin , intoxication with Clostridium. perfringens A, BClostridium. perfringens A, Bacillusacillus cereus cereus
Bacterial reduction of nitrates to nitrites: Bacterial reduction of nitrates to nitrites: methemoglobinemia, nitrosaminesmethemoglobinemia, nitrosamines
Lipolytic and proteolytic effects of microorganismsLipolytic and proteolytic effects of microorganisms
Nitrosamines
Nitrates
Nitrites
Methemoglobinaemia of infants
(+ amines)
Nitrosamines
Bacterial reductases
+ acidic pH
Vit. C, E
Smoked meat: mixture Smoked meat: mixture of nitrate and nitrite of nitrate and nitrite saltssalts
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
Product of Maillard reactionProduct of Maillard reactionThe The Maillard reactionMaillard reaction is a form of is a form of
nonenzymatic browning. It results from a nonenzymatic browning. It results from a chemical chemical reactionreaction between an amino acid and between an amino acid and a reducing sugar, usually requiring heat. It can a reducing sugar, usually requiring heat. It can be formed in starchy be formed in starchy foodsfoods during cooking. during cooking.
Formation during the production of chips, bread, Formation during the production of chips, bread, cakes etc. The amount depends somehow on cakes etc. The amount depends somehow on the technology usedthe technology used
Changes in frying oil = changes in frying foodsChanges in frying oil = changes in frying foods
Chemical reaction during frying:Chemical reaction during frying:
1. Hydrol1. Hydrolysis due to water vapour released from frying ysis due to water vapour released from frying food. Acrolein, originated in final phase, is irritating food. Acrolein, originated in final phase, is irritating agents for eyes and mucous tissues. agents for eyes and mucous tissues.
2. Oxida2. Oxidativetive rea reactionsctions – – especially in longer used oils, especially in longer used oils, where the presence of polar compounds facilitates where the presence of polar compounds facilitates foaming. foaming.
3. 3. Formation of hydroperoxidesFormation of hydroperoxides – oxida – oxidation of mono-ene tion of mono-ene and saturated fatty acidsand saturated fatty acids
4. Cumulating of polymers in frying oil4. Cumulating of polymers in frying oil
Adverse consequences of Adverse consequences of frying:frying:
Oxidation of blood lipids, namelyOxidation of blood lipids, namely LDL cholesterol, LDL cholesterol,
Oxidative products cumulated in macrophages Oxidative products cumulated in macrophages constitute a basis of atherosclerotic plate in walls of constitute a basis of atherosclerotic plate in walls of blood vessels. blood vessels.
Lipid peroxidation generates a complex variety of Lipid peroxidation generates a complex variety of products; some of them react with proteins and DNA products; some of them react with proteins and DNA (damage of DNA, genotoxicity, carcinogenicity(damage of DNA, genotoxicity, carcinogenicity
Chemoprevention by means of antioxidants in fruits, Chemoprevention by means of antioxidants in fruits, vegetables, green tea etc.vegetables, green tea etc.
Adverse consequences of Adverse consequences of frying: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.
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
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
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.)
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)
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!!!
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
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
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
DryingIncreases the level of heavy metals contaminated vegetable, herbs, herb-teas etc. (Cd, Pb)
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
GMO and food productionGMO 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 costsContr: 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
GMO and food production GMO and food production (cont.)(cont.)
• Resistance to viruses, bacteria and fungies
• Increased tolerance to abiotic stress
(dryness, salinity) • Increase of iron bioavailability
GMO and food productionGMO 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)
GMO and food productionGMO 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)
GMO and food productionGMO 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);
Further potential GMO utilisationFurther 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)
Potential health and Potential health and environmental risks of GMO?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
Message to take withMessage 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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