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FEDERAL UNIVERSITY 0F AGRICULTURE COLLEGE OF FOOD SCIENCE AND HUMAN ECOLOGY. W E L C O M E ! To the class: Course code:FST 507 Course title: FOOD ADDITIVES,TOXICOLOGY AND SAFETY 1 ST SEMESTER, 2011/2012 SESSION Lecturer: PROF F. O. HENSHAW E-mail henofcpc@yahoo.com

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federal university 0f agriculture college of food science and human ecology

FEDERAL UNIVERSITY 0F AGRICULTURE COLLEGE OF FOOD SCIENCE AND HUMAN ECOLOGY

W E L C O M E !

To the class:

Course code:FST 507Course title: FOOD ADDITIVES,TOXICOLOGY AND SAFETY

1ST SEMESTER, 2011/2012 SESSION

Lecturer: PROF F. O. HENSHAW

E-mail henofcpc@yahoo.com

fohenshaw@unaab.edu.ng

Phone: 234 8034056311

course requirements
Course requirements
  • Number of units: 3 units
  • Lecture period: 2 hour /week(30 hours/semester)
  • 75% attendace is required to qualify to sit final examination
  • One Practical period 3hour/week
  • Grading

take home assignment 10%

A short quiz in class 20%

Final Examination 70%

course learning objectives
Course Learning Objectives

Upon successful completion of the course students should:

  • Have broad base knowledge about sources, nature and control of toxic substances in human food system
  • Acquire critical thinking and analytical skills in risk assessment
  • Have a high level of understanding and interpretative capacity in food science and toxicology interface.
course outline
COURSE OUTLINE

1. DEFINITIONS OF TERMS; TOXICOLOGY, ADDITIVES AND SAFETY

slide5
2. Toxicity and Safety evaluation
  • Naturally occuring Toxins

Mycotoxins

Glycoalkaloids

Glucosinolates

Antinutritional factors

Phycotoxins

slide6
4. Food additives

Antioxidants

Preservatives

Colourants

Emulsifiers and Stabilisers

Sweetners

Miscellaenous Additives

slide7
5. Effect of Processing on Toxicity

6. Safety of Food additives

  • Food Processing and Toxicity
  • Irradiation and Toxicity
  • Microbial Toxicity
slide8
FOOD ADDITIVES—Any substance/mixture of substances other than the basic component that is added to food as a result of any aspect of processing, storage and preservation

TOXICOLOGY: multi-disciplinary application of Scientific knowledge to the study of toxins and their effects on people, animals, wildlife and the environment.

slide9
Toxicology is the most diversified of all Scientific disciplines, so Toxicologists usually specialize in some aspect of toxicology e.g
    • Medical Toxicology/ Clinical Toxicology: diagnosis and treatment of human diseaeses caused by poisons
    • Veterinary Toxicology: diagnosis and treatment of diseases of domesticated and wildlife caused by poisons
slide10
Food toxicology is the study of the nature, properties, effects and detection of toxic substances in food and their disease manifestation in humans
slide11
Forensic Toxicology: deals with the legal and medical aspects of poisons in people and animals;
  • Environmental Toxicology- deals with effects of pollutants on the environment and wildlife
slide12
Safety: is the absence of evidence of toxicity
  • Toxicity is ability to cause harm/adverse effect
  • A toxin/poison is difficult to define as many substances present in food would have adverse/toxic effects if taken in large/sufficient dose
natural vs synthetic chemicals
NATURAL vs SYNTHETIC CHEMICALS
  • Are natural chemicals safer than synthetic chemicals?
  • Which set pose a greater risk?
  • Which set is more amenable to control and regulation?
  • Fundamental concept of Toxicology: all substances can be toxic it is a matter of DOSE
slide14
Safety is relative and there is no absolute safety
  • Thus there are toxic and non toxic doses for any substance
  • Frequency-response curve: a plot of the % of individual with specific response as a function of dose
slide17
TOXICOLOGICAL TERMS

Toxin /Toxicant: A substance that has been shown to present some significant degree of possible risk when consumed in sufficient quantity by humans or animals

Natural/Inherent :Toxicants occur in Foods as a result of biosynthetic origin

slide18
Acute Toxicity
  • Chronic Toxicity
  • Sub-chronic feeding test
  • Maximum tolerated dose (MTD)
  • No observable adverse effect level (NOAEL)
  • Acceptable daily intake (ADI)
  • Lethal dose fifty (LD50)
slide19
Tumor dose fifty (TD50)
  • GRAS
  • Acute toxicity: toxic response ,often immediate, induced by single exposure.
  • The acute toxicity of a substance is defined by its LD50 / lethal dose that will kill 50% of a group of exposed animals
slide22
Chronic toxicity: Toxic effect that requires some time to develop, e.g cancer.
  • Testing for chronic toxicity involve continuous feeding of the test substance to rodents for 20-24 months.
slide23
By analogy to LD50, the amount of a carcinogen required to induce cancer in 50% of a group of exposed animal is referred to as TD50

,

slide24
New approaches to safety evaluation may be required for Genetically modified foods|(GMOs)
  • Comparative toxicology concept
  • New approaches to safety evaluation may be required for Genetically modified foods|(GMOs)
  • Comparative toxicology concept
slide26
Risk assessment
  • – Scientific evaluation of the probability of harm resulting from exposure to toxic substances.
slide27
Risk communication
  • – The science of communicating effectively in situations that are of high concern, sensitive, or controversial. Risk communication principles serve to create an appropriate level of outrage, behavior modification, or mitigating response, that is in direct proportion to the level of risk or hazard.
slide28
Risk management
  • – Risk management is the decision-making process involving considerations of political, social, economic and science/engineering factors with relevant risk assessments relating to a potential hazard so as to develop, analyze and compare options and to select the optimal response for safety from that hazard.
slide29
Risk characterization
  • – A description of the nature and magnitude of health risk that combines results of exposure assessment and hazard identification and describes the uncertainty associated with each step.
slide30
Protocols have been established for safety evaluation of foods and substances used in foods
  • Acute toxicity
  • Genetic toxicity
  • Subchronic
  • Chronic
  • Teratogenesis
slide31
Traditional high dose feeding of a few rats/other rodents
  • A safety margin of a 100-fold is usually applied from the NOAEL (no observable adverse effect level) to determine safe dose for man, i.e the ADI (acceptable daily intake).
slide32
New approaches to safety evaluation may be required for Genetically modified foods|(GMOs)
  • Comparative toxicology concept
natural plant toxins
Natural plant Toxins
  • Naturally ocurring toxic components in plant foodstuffs
  • Have negative effects on bio availability of nutrients ;anti- nutritional factors/anti-nutrients
  • Produced as part of plant defense against bacteria, insects and other threats
slide34
Glycoalkaloids
    • Are steroidalkaloids coupled to one or more monosaccharides
  • Occurrence: the genus Solanum e.g; eggplant, potato, tomatoes
    • Potato; α-Solanine and α- Chaconine
    • Tomato: Tomatine

Properties

fairly heat stable ,not decomposed during cooking,

not water soluble

slide35
Average composition in potato: 20-100mg/kg fresh tissue

Concentration is higher in sprouts, peels and green areas

~3mg/kg body weight can induce toxicity

Human intoxication:Gastro intestinal disorder (abdominal pain, nausea, and diarrhea)

> LD50 admnister as oral dose in sheep, rat and mice:500, 600, and 100mg /kg respectively

slide37
Goitrogens: components that exhibit adverse effect on the thyroid gland function e.g;
    • Glucosinolates
    • Cyanogenic glucosides
    • Soy factor

Glucosinolates are sulphur- containing glucoside

Occurrence: plant family crucifereae of the genus. E.g Brassica ebbage, Cauliflower flower,