Download to read offline
FST 507.ppt
- 1. FEDERAL UNIVERSITY 0F AGRICULTURE COLLEGEOF 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 1ST SEMESTER, 2011/2012 SESSION Lecturer: PROF F. O. HENSHAW E-mail henofcpc@yahoo.com fohenshaw@unaab.edu.ng Phone: 234 8034056311
- 2. Course requirements • Numberof 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%
- 3. Course Learning Objectives Upon successfulcompletion 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.
- 4. COURSE OUTLINE 1.DEFINITIONS OFTERMS; TOXICOLOGY, ADDITIVES AND SAFETY
- 5. 2. Toxicity andSafety evaluation 3. Naturally occuring Toxins Mycotoxins Glycoalkaloids Glucosinolates Antinutritional factors Phycotoxins
- 6. 4. Food additives Antioxidants Preservatives Colourants Emulsifiersand Stabilisers Sweetners Miscellaenous Additives
- 7. 5. Effect ofProcessing on Toxicity 6. Safety of Food additives 7. Food Processing and Toxicity 8. Irradiation and Toxicity 9. Microbial Toxicity
- 8. FOOD ADDITIVES—Any substance/mixture ofsubstances 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.
- 9. • Toxicology isthe 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
- 10. • Food toxicologyis the study of the nature, properties, effects and detection of toxic substances in food and their disease manifestation in humans
- 11. • 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
- 12. • Safety: isthe 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
- 13. 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
- 14. • Safety isrelative 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
- 15.
- 16.
- 17. • 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
- 18. • 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)
- 19. • Tumor dosefifty (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
- 20. • LD50 isalso used to determine the level of toxicity LD50 (/Kg body weight substance 200mg Caffeine 100ng Botulinum toxin 40g Sodium chloride
- 21. LD50 Toxicity Level ≤1mg Extremely Toxic 1-50mg Highly toxic 50-500mg Moderately toxic >500mg Non Toxic
- 22. • 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.
- 23. • By analogyto LD50, the amount of a carcinogen required to induce cancer in 50% of a group of exposed animal is referred to as TD50 ,
- 24. • New approachesto 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
- 25.
- 26. • Risk assessment •– Scientific evaluation of the probability of harm resulting from exposure to toxic substances.
- 27. • 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.
- 28. • 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.
- 29. • 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.
- 30. • Protocols havebeen established for safety evaluation of foods and substances used in foods • Acute toxicity • Genetic toxicity • Subchronic • Chronic • Teratogenesis
- 31. • Traditional highdose 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).
- 32. • New approachesto safety evaluation may be required for Genetically modified foods|(GMOs) • Comparative toxicology concept
- 33. 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
- 34. • Glycoalkaloids – Aresteroidalkaloids 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
- 35. • 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
- 36.
- 37. • Goitrogens: componentsthat 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,