15. Food standards

Common market authorisation procedure of chemicals

Residues of pesticides

• Very tightly regulated

• Pesticide products contain at least one active substance to kill insects/weeds

  • No active chemical = it is not pesticide

• Active substance must be approved

  • ADI must be set

• Residues

  • Traces of active ingredients in treated products

• Maximum residue levels: highest level of a residue that is legally tolerated in or on food

  • Good agricultural practices

Exposed populations to residues of pesticides

Operators: performs activities relation to the applicaiton:

• At factory

• Farmers

• Amateur users

Bystanders:

• Presence is quite incidental and unrelated to work

• Exposed during a short period of time (Acute exposure)

• Take no action to avoid or control exposure

Residents:

• Lives, works or attends school clsoe to an area

• Presence is unrelated to work involving PPPs

• Take no action to avoid or control exposure

• Might be in the location for up to 24 hours per day

Workers:

• as part of employment entering an area

• Handling a crop that has been treated

Essential information to known regarding residues of pesticides?

• Toxicological profile of the active substance

  • ADI or BMDL must be determined

• Toxicological information of the plant protection product

• Population(s) exposed

  • Different based on ages?

• Exposure scenario

  • outdoor/indoor?

  • dose level?

  • route of exposure?

  • etc

What are the two streams of assessment in pesticide regulation?

Stream one:

• Looks at substance or product that substance is in and toxicological profile

Stream two:

• A certain concentration is necessary to be effective - good agricultural practice

• Maximum residue level (MRL) - is determined to see what the maximum amount is that is necessary for the pesticide to be effective.

• This has NOTHING to do with safety.

Residues of veterinary medicines

• Scientific advice European medicines Agency

  • Set ADI based on toxicological profile of active ingredient

  • Study efficacy and toxicity of product with active ingredient

  • Set MRL in tissues

• Medicine are also applied in different ways (injection, pill, etc) these all affect how medicine affects body

Residues of veterinary drugs “Food Basket”

• This food basket is an assumption of how much meat we eat

• Based on that assumption they can determine how many veterinary drugs you consume and what level of veterinary drugs are safe

Which chemicals end up in the meat? (veterinary drugs)

• During metabolism the drug is changed by the body (especially the liver)

• Therefore the question is if the metabolite that is left is dangerous

• Also concentrations change over time and after a certain amount of time the metabolite (marker residue) has decreased below the MRL and is safe (see picture)

• Therefore an ADI is set for the active ingredient but an MRLs for the species and tissue.

• Withdrawal period is sometimes set if needed to remove marker residue.

Maximum levels of contaminants in food

• Maximum levels should be set at a strict level which is reasonably achievable by following good agricultural, fishery and mnaufacturing practices and taking into account the risk related to the consumption of the food.

• To ensure an efficient protection of public health, products containing contaminants exceeding the maximum levels should not be placed on the market either as such, after mixture with other foodstruffs or used as an ingredient in other foods

How are maximum levels of contaminants in food determined for non-genotoxic contaminants?

• Non-genotoxic contaminants

  • No producer (industry) involved

  • Data from scientic literature

  • Specific EU funded research projects

• Set a TDI

• MRL based on:

  • TDI or,

  • Sensitivity or, sensitivity of analytical methods

Contaminants in food for genotoxic contaminants

• MRL is based on:

  • ALARA principle

  • Margin of exposure

  • Sensitivity of analytical methods

Industrial chemicals legislation

• Europe: REACH Registration Evaluation and Authorization (and Restriction) of CHemicals

• Producer has to provide toxicity data on their chemical in order to allow the chemical on the market

• Many ‘existing’ chemicals need to be tested

Combination toxicology

• The idea that we know for a lot chemicals how they are dangerous by themselves but we do not know their risks when combined

• The three ways in which chemicals exist with each other:

  • Similar action

  • Dissimilar actions

  • Interactions

Dissimilar action (response-addition)

• Separate mechanisms/modes of action

• Chemicals do not influence each other’s action

• Effects of combination: sum of the effects of the compounds (response addition)

• If each chemical is present at doses below ADI/TDI, no adverse effects of mixture expected

Similar action (dose-addition)

• Same mechanism/modes of action, possible differences in potencies

• Effect of combination: effects of the sum of the compounds (dose addition)

• Even if each chemical is present at doses below ADI/TDI, adverse effects may be induced

• Dioxins/PCBs → activate aryl hydrocarbon receptor

• Organophosphates → inhibit acetylcholinesterase (AChE)

Relative potency factor (RPF)

Potency of chemical congener as a relative potency compared to the index chemical

Index chemical

A potent congener of a chemical group for which adequate data are available for the risk assessment (hazard characterization)

Interactions

• Interaction effects may be expected when a chemical affects:

  • Uptake of another

  • Biotransformation of another

    • Competition for enzymes

    • Enzyme induction

  • Excretion/clearance of another