Food Toxicology Group 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 ( )  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.

LD 50 : 

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: