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.

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.

Mycotoxins

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Toxiny bakterií

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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

• contact insecticides:
  • DDT, heptachlor,

hexachlorobenzene (HCB)

• • • further: γ-HCH, lindane, hexachloran, pentachlorophenol, aldrin, dieldrin, toxaphene,,

Representatives

Modern insecticides

• chlorpyrifos (organophosphate)
• aldicarb (carbamate)
• permethrin (pyrethroid)
• diflubenzuron (benzoylurea esters)

Herbicides

• 2,4-D (phenoxyalkanoic acids)
• atrazine (triazine)

Fungicides

• zineb (ethylenebisdithiocarbamate, M = Zn)

Transformation of pesticides

• formation of less toxic and non-toxic products

- permethrin hydrolysis

• the emergence of products with an enhanced toxic effect (dicofol from DDT)
  • transformation of parathion to paraoxon
  • transformation of carbosulfan to carbofuran

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:

Toxicological assessment

• inhibition of acetylcholinesterase
• inhibition of oxidative phosphorylation
• potential human carcinogens
• estrogenic effects

Other contaminants

Ethyl Carbamate

• a natural component of fermented products
• potential human carcinogen
• hygienic limits for wine, fruit spirits

Origin and main sources

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)

• 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.

Links

Source

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