Contaminants of food

Contaminant entry into food (unintentional):


 * agricultural primary production;
 * environmental pollution;
 * storage, transport, sale;
 * technological and culinary processing.

Classification


 * primary (exogenous) contaminants − external sources;
 * secondary (endogenous) contaminants − arising in food.

Sources of contamination

 * Agricultural production
 * use of pesticide preparations;
 * fertilization;
 * imise, emission ;
 * use of irrigation surface water;
 * attack by microorganisms, especially fungi;
 * veterinary treatment.
 * Storage and processing
 * post-harvest application of pesticides;
 * arising from relatively non-toxic pesticides;
 * attack by microorganisms;
 * technological or culinary modifications;
 * penetration of plastic additives.
 * penetration of plastic additives.

Evaluation criteria

 * potential risks and severity of negative effects on human health
 * the frequency of cases where a given foreign substance has been proven to be the cause of human or animal intoxication
 * frequent occurrence in foods representing important items of the food basket
 * persistence and frequency of occurrence of the given contaminant in the environment, possible conversion to products with higher toxicity, ability to accumulate in the human food chain
 * the volume of inputs (emissions) of the given contaminant into the environment from industry, agriculture, urban agglomerations and other sources
 * the importance of the food in which the given contaminant occurs, from the point of view of international trade

Priority contaminants

 * mycotoxins and other microbial toxins
 * toxic minerals
 * radioactive isotopes
 * nitro compounds
 * polycyclic aromatic hydrocarbons
 * halogenated organic compounds
 * pesticide residues
 * residues of veterinary drugs
 * other contaminants (ethyl carbamate, contaminants from packaging)

Standards and recommendations − Codex Alimentarius FAO/WHO

Legislation in the Czech Republic − Food and Tobacco Products Act No. 110/1997 Coll., Decree No. 298/1997 Coll.

Nitro compounds

 * reaction products of secondary amines with nitrosating agents
 * secondary amines: Amino acids, biogenic amines, etc.
 * nitrosating agents: Nitrosyl cation NO +, nitrogen oxides
 * factors: pH, temperature, time, catalysts, reaction inhibitors


 * Classification


 * volatile nitrosamines: N-nitrosodimethylamine ... content
 * non-volatile nitrosamines: N-nitrososarcosine ... content


 * Toxicology


 * mutagenic, teratogenic, especially carcinogenic effects


 * NDMA = N-nitrosodimethylamine
 * NDEA = N-nitrosodiethylamine
 * NPIP = N-nitrosopiperidine
 * NPYR = N-nitrosopyrrolidine.

Pesticides

 * higher yields
 * negative effects of chemical treatment
 * Classification
 * according to the target harmful agents
 * insecticides (insects)
 * Acaricides (Arachnids)
 * fungicides (fungi, fungi)
 * herbicides (weeds)
 * molluscicides (mollusks)
 * rodenticides
 * plant growth regulators, desiccants (cultivated plants)
 * according to the mode of action
 * contact
 * systemic
 * gluttonous
 * respiratory
 * according to the mechanism of biological action

Insecticides

 * interaction with cell membranes, neurotoxicity
 * (persistent chlorinated hydrocarbons)
 * inhibition of acetylcholinesterase, neurotoxicity (organophosphates, carbamates, pyrethroids)
 * inhibition of chitin biosynthesis (benzoylurea esters)

Herbicides

 * interference with nucleic acid biosynthesis
 * (phenoxyalkanoic and benzoic acids)
 * interference with photosynthesis (triazines, uracils)
 * reactions with cell membranes (bipyridyl)
 * germination retardation (nitroaniline) fungicides
 * inhibition of enzyme systems (ethylenebisdithiocarbamates, phthalimides)
 * interference with DNA biosynthesis (benzimidazoles)

Persistent chlorinated hydrocarbons
hexachlorobenzene (HCB)
 * contact insecticides:
 * DDT, heptachlor[[File:heptachlor.jpg]],
 * further: γ-HCH, lindane, hexachloran, pentachlorophenol, aldrin, dieldrin, toxaphene,,

Modern insecticides

 * chlorpyrifos (organophosphate) [[File:organofosfát.jpg]]
 * aldicarb (carbamate) [[File:karbamát.jpg]]
 * permethrin (pyrethroid) [[File:pyrethroid.jpg]]
 * diflubenzuron (benzoylurea esters) [[File:diflubenzuron.jpg]]

Herbicides

 * 2,4-D (phenoxyalkanoic acids) [[File:fenoxyalkanové.jpg]]
 * atrazine (triazine) [[File:atrazin.jpg]]

Fungicides

 * zineb (ethylenebisdithiocarbamate, M = Zn) [[File:zineb.jpg]]

Transformation of pesticides
- permethrin hydrolysis
 * formation of less toxic and non-toxic products
 * the emergence of products with an enhanced toxic effect (dicofol from DDT)
 * transformation of parathion to paraoxon [[File:transformace-parathionu.jpg]]
 * transformation of carbosulfan to carbofuran [[File:transformace-karbosulfanu.jpg]]


 * The influence of technological operations and culinary modifications


 * degradation, volatilization, selection of the edible part
 * concentration of the residue in the given proportion
 * formation of toxic degradation products:[[File:ethylenbisdithiokarbamát-ethylenthiomočovina.jpg]]
 * Toxicological assessment
 * inhibition of acetylcholinesterase
 * inhibition of oxidative phosphorylation
 * potential human carcinogens
 * estrogenic effects

Ethyl Carbamate



 * a natural component of fermented products
 * potential human carcinogen
 * hygienic limits for wine, fruit spirits
 * Origin and main sources
 * [[File:vznik-ethylkarbamátu.jpg]]
 * Impact of technological operations
 * light, fermentation temperature
 * special copper catalysts
 * reduction of precursor content

Contaminants from packaging materials

 * corrosion, migration
 * metals
 * glass and ceramics
 * paper
 * wood
 * polymeric materials
 * residues of starting materials
 * residues of auxiliary substances (additives)
 * residues of degradation products or additives

Phthalates

 * plasticizers
 * ubiquitous organic contaminants
 * possible teratogenic, carcinogenic effects
 * estrogenic activity
 * hygienic limits
 * permissible amount for spirits 1.0 mg·kg -1 (sum of DBP, DEHP)
 * [[File:ftaláty.jpg]]
 * dibutyl phthalate R = R 1 = (CH 2 ) 3 CH 3
 * bis(2-ethylhexyl)phthalate R = R 1 = CH 2 CH(CH 2 CH 3 )(CH 2 ) 3 CH 3


 * Occurrence in food
 * contamination of raw materials and intermediate products
 * contamination of finished products from packaging


 * Factors affecting migration
 * type of polymeric packaging material
 * type of food
 * temperature
 * contact time
 * the amount of fat in the food, etc.
 * the amount of fat in the food, etc.

Source

 * DAVIDEK, Jiří. 14. FOOD CONTAMINANTS  [online]. [feeling. 2012-03-13]. < https://el.lf1.cuni.cz/p92009169/ >.

Categorie:Nutritional therapy