FOOD TOXICOLOGY

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FOOD TOXICOLOGY

• ENVS 531
• Sunitha Yerragodula

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Uniqueness of food toxicology

• Nature of food makes it unique
• Food is subjected to unpredictable forces of
  nature and hence unreliable.
• Assessment of safety of substances added to food,
  natural substances in food,

• Safe is a term which is most used in food
  toxicology
• An understnading of this term is necessary in
  deciding how many and what types of studies must
  be conducted to determine that an added substance
  is safe.

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Contd

• There is no explicit definition for the term
  safety, of substances added to food.
• The one principle on which there is unanimous
  agreement is that safety concerns should focus on
  both the nature of the substance and its
  intended conditions of use.

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GI Tract

• Toxicological studies mostly focus on the
  digestion and metabolism occurring in the GI
  tract.
• The reason for this focus is that in most cases
  it is not the ingested substance that is absorbed
  through the GI tract it is products of its
  digestion that are absorbed.
• And hence GI tract is important.

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GRAS

• Generally regarded as safe
• Scientific experts determine whether a substance
  that is to be added to a food is GRAS.

• In addition to GRAS the FDC Act provides a class
  of substances that are regulated as food
  additives, which are not generally recognized to
  be safe.
• Hence there is a legal distinction between GRAS
  and Food additives

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Tolerance

• A food may be declared unfit if it contains
  unavoidable contaminant that may render the food
  injurious.
• But, an unavoidable contaminant in food, need
  only pose a risk to be found unfit and subject to
  FDA action.
• At times, foods containing unavoidable
  contaminants cannot be banned.

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Contd..

• Under provisions of Sec 406 of the FDC Act, the
  quantity of the unavoidable contaminant in food
  may be limited by regulation.
• Ex Action levels for Aflatoxin in peanuts,
  grain, and milk.

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Food and Color additives

• Any intentionally added ingredient, not
  considered GRAS is either a food additive or
  color additive.
• A color additive has generally only one function,
  while food additives have 32 functionalities.

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Food and Color additives
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Contd..

• Color additives consist of aromatic amines or
  aromatic azo structures.
• FDC Act permits such colors still.
• The reason being the sulfonation of these
  compounds.
• Beverages, Candy and Confections, Bakery goods,
  Sausages etc.. Are some of the foods that utilize
  food additives.

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Safety evaluation of direct food and color
additives

• Estimated daily intake
• EDI CI
• C is the concentration of the substance added in
  that food
• I is the daily intake of the food in which the
  substance will be used.

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Transgenic Plant
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Carcinogenicity

• The Delaney clause, prohibits the approval of
  regulated food additives found to induce cancer
  when ingested by man or animals .
• One of the draw backs is that it applies to only
  food additives, color additives, and animal drugs
  but not to unavaoidable contaminants or GRAS
  substances sanctioned by the FDA before 1958.

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Adverse Reactions to food or food ingredients

• FOOD Allergy Immune mediated reaction
• FOOD Idiosyncracy Quantitatively abnormal
  response- not an immune mediated reaction, buta
  genetically predisposed reaction.
• Anaphylactoid reactions
• Pharmacologic food reactions.
• Metabolic food reactions.

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Foods for which tolerances can be set

• Pesticide residues in food
• Heavy metals like Pb, As, Cd.
• Chlorinated organics.

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Substances for which tolerance can not be set

• Toxins in Fish, Shell fish, turtles
• Microbiologic agents, like Clostridium
  botlulinum, Clostridium butyricus, E.coli.
• Bovine spongiform Encephalopathy
• Substances produced by cooking.

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Why ??????

• Because they are regarded as avoidable or of such
  hazard that a safe level cannot be set, therefore
  the FDA has determined that food containing such
  substances is banned or
• Beyond the control of the FDA and cannot be
  regulated

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Reference

• Chapter 30, Food Toxicology, Casarett Doulls
  Toxicology, Curtis D.Klaassen, 2001 edition.

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Questions

• Aromatic amines are added in Color additives,
  despite their known toxicity. Why?
• Why does the population in Southeast Asia more
  prone to symptoms like malabsorption and diarrhea?