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

1. 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

2. 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%

3. 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.

4. COURSE OUTLINE 1. DEFINITIONS OF TERMS; TOXICOLOGY, ADDITIVES AND SAFETY

5. 2. Toxicity and Safety evaluation • Naturally occuring Toxins Mycotoxins Glycoalkaloids Glucosinolates Antinutritional factors Phycotoxins

6. 4. Food additives Antioxidants Preservatives Colourants Emulsifiers and Stabilisers Sweetners Miscellaenous Additives

7. 5. Effect of Processing on Toxicity 6. Safety of Food additives • Food Processing and Toxicity • Irradiation and Toxicity • Microbial Toxicity

8. 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.

9. 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

10. Food toxicology is 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: 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

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 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

15. Cumulative response-curve(compounds A and B)

16. Dose-response curve

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 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

20. LD50 is also used to determine the level of toxicity

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 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 ,

24. 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

25. Toxicology and risk analysis

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 have been established for safety evaluation of foods and substances used in foods • Acute toxicity • Genetic toxicity • Subchronic • Chronic • Teratogenesis

31. 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).

32. New approaches to 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 • 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

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. Structure of solanine/chaconine

37. 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,