food toxicology group a. food toxicology: overview definition: food toxicology is the study of the...

Food ToxicologyGroup A

Food Toxicology: Overview

Definition:

Food toxicology is the study of the nature, properties, effects, and detection of toxic substances in food, and their disease manifestation in humans.

Introduction

Historical background

Historical Background

“All substances are poisons, there is none which is not a poison. The right dose differentiates a poison from a remedy” ----Paracelsus (1493-1541)

Percival Pott

Orfila Father of modern toxicology

Developed methods to quantify poisons

Causes of Food Toxicity

3 types

Biological

Chemical

Physical

Causes of Food Toxicity

Bacteria and Viruses

Parasites

Fungi

Allergens

Example

Compylobacteriosis

Causes: Compylobacter jejuni

Diarrhea, vomiting and abdominal pain

Carrier: Raw poultry, Raw milk, undercooked poultry, Animal feces

Intrinsic Toxins

Present naturally in the food

Reduction by the suitable processing

Requires careful Food selection

For example, solanine is present in green part and sprouts of potatoes.

Intrinsic Toxins

Different categories of toxin depending upon its harmful effect

Goitrogens:

Direct effect on thyroid gland and cause goiter

Cassava beans contains these toxic compounds

Soaking, prior to cooking, can detoxify food.

Tannins:

Causes astringent and bitter taste

Carcinogen and Genotoxic effect

Careful selection of food can reduce chances of intoxication

Intrinsic Toxins

Phytoestrogens:

Non steroid compound

Structural similarity with steroidal which is steroid.

Food source may be rice, apples sesame seeds etc.

Cause cancer, disorders in reproductive system and osteoporosis

Phytates:

Food source are walnuts, paenuts and brown rice

Binds with iron to cause anaemia

Intrinsic Toxins

Antivitamins:

Replaces vitamin K due to structural similarity

Works anticoagulant of proteins

Extrinsic Toxins

Added externally either during processing or after processing

Contamination

Fungal toxins:

Aspergillus spp, Fusariuam spp, Penicillium spp.

Aflatoxins:

Aflatoxicosis

Produced by Aspergillus spp.

Sources are nuts, rice, meat, cottonseed

Carcinogenic

Extrinsic Toxins: Bacterial Toxins

Bacillus cerues:

Present in soil, dust and water

Produce a toxin “ cereulide”

Carrier is poorly cooked food

Causes nausea, abdominal cramps and vomiting

Clostridium perferingens

Present in soil and tract of human and animal

Produces “ lecithenase”

Carriers are turkey, chicken and beefs

Extrinsic Toxins: Chemical Toxins

Fertilizers:

Residues are present in food

Soil acidulation

Heavy metal accumulation

May present due to fertilizers residue or nearby industrial waste

Cadmium

Fluorine

Zinc

Calcium- low toxic

Principals of Food Toxicology

Food Toxicology

Food toxicology is concerned with assessing the injurious effects on living systems of chemicals present in foods and feeds.

Examine adverse effects ranging from acute to long-term

Naturally occurring or added by the environment

Toxicants

A poison or toxicant is the chemical that is harmful to living organisms because of its detrimental effects on tissues, organs, or biological processes

Four factors influence toxicity:

The toxic substance itself

The matrix in which it is present

The circumstances of exposure

The organism and its environment.

Classification of Toxicants

Heavy metals

Microbial toxins

Pesticides

Mushroom toxins

Plant toxins

Animal toxins

Food Allergens

Cyanides

Toxicology Paradigm

Toxicokinetics

Toxicokinetics describes the fate of toxic compound in the body.

Absorption

Ditribution

Biotransformation

Excretion of Toxic compounds

Sometimes called as Pharmacokinetics

Toxicokinetics

Toxicodynamics

Toxicodynamics describes the determination and quantification of the sequence of events at the cellular and molecular levels leading to a toxic response to an environmental agent

Sometimes referred to as pharmacodynamics.

Toxicokinetics VS Toxicodynamics

Toxicity Testing

To estimate the levels of the substance to which the population is exposed.

Acute Toxicity: to determine the level of the substance which induces mortality in laboratory animals.

Genetic Toxicity: to determine the tendency of the substance to induce mutations in the test organism.

Metabolism: to gain both a general and a quantitative understanding of absorption, biotransformation and disposition of the toxic substance

Difference Between Allergies and Toxic Reactions

Toxic effect is directly the result of the toxic chemical acting on cells

Allergic responses are the result of a chemical stimulating the body to release natural chemicals which are in turn directly responsible for the effects seen.

Most Common Food Allergens

Routes of Toxic Exposure

Ingestion

Toxics present in food items, cosmetics, household products

Inhalation

Aerosols, toxic gases, vapors

Surface absorption

Poison, ivy, oak, cosmetics

Injection

Intentional injection of illicit drugs, stings/bites

Routes of Toxic Exposure

Ingestion

Common agents:

Household products

Petroleum-based agents

Cleaning agents

Cosmetics

Drugs, plants, or foods

Absorption occurs in the

stomach and small intestine.

Sub-disciplines of Toxicology

Analytical toxicology

Clinical toxicology

Forensic toxicology

Industrial (occupational) toxicology

Environmental toxicology

Regulatory toxicology

Dose-Response Relationship:

Fundamental and essential concept.

The higher the dose, the more severe the response.

Based on observed data from experimental animal, human clinical, or cell studies.

Dose-Response curve:

Dose-Response relationship is illustrated by Dose-Response curve.

LD50:

Graphical Representation:

Variation is Dose-Response curves:

There is variation in Dose-Response curves in following parameters:

Predictability

Potency

Margin of safety

Potency vs. Efficacy

Interaction of chemicals

Potency:

Potency Vs. Efficacy:

Interaction of Chemicals:

Interaction of chemicals occur in three ways:

Additive Effect

Synergistic Effect

Antagonism

Additive Effect:

Synergistic Effect:

Antagonism: