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FEDERAL UNIVERSITY 0F FEDERAL UNIVERSITY 0F AGRICULTURE AGRICULTURE
COLLEGE OF FOOD SCIENCE AND COLLEGE OF FOOD SCIENCE AND HUMAN ECOLOGYHUMAN ECOLOGY
FEDERAL UNIVERSITY 0F FEDERAL UNIVERSITY 0F AGRICULTURE AGRICULTURE
COLLEGE OF FOOD SCIENCE AND COLLEGE OF FOOD SCIENCE AND HUMAN ECOLOGYHUMAN ECOLOGYW E L C O M E !W E L C O M E !
To the class:To the class:Course code:FST 507Course code:FST 507
Course title: FOOD ADDITIVES,TOXICOLOGY Course title: FOOD ADDITIVES,TOXICOLOGY AND SAFETYAND SAFETY
11STST SEMESTER, 2011/2012 SESSION SEMESTER, 2011/2012 SESSION
Lecturer: PROF F. O. HENSHAWLecturer: PROF F. O. HENSHAWE-mail E-mail [email protected]@yahoo.com
[email protected]@unaab.edu.ngPhone: 234 8034056311Phone: 234 8034056311
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 Examination70%
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.
2. Toxicity and Safety evaluation
3. Naturally occuring Toxins MycotoxinsGlycoalkaloidsGlucosinolatesAntinutritional factorsPhycotoxins
4. Food additivesAntioxidantsPreservativesColourantsEmulsifiers and StabilisersSweetnersMiscellaenous Additives
5. Effect of Processing on Toxicity6. Safety of Food additives7. Food Processing and Toxicity8. Irradiation and Toxicity9. Microbial Toxicity
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.
• 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
• Food toxicology is the study of the nature, properties, effects and detection of toxic substances in food and their disease manifestation in humans
• 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
• 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
• 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
• 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
• TOXICOLOGICAL TERMSToxin /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
• 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)
• 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
• LD50 is also used to determine the level of toxicity
LD50 (/Kg body weight
substance
200mg Caffeine
100ng Botulinumtoxin
40g Sodium chloride
LD50 Toxicity Level
≤ 1mg Extremely Toxic
1-50mg Highly toxic
50-500mg Moderately toxic
>500mg Non Toxic
• 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.
• 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
,
• 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
• Risk assessment• – Scientific evaluation of the
probability of harm resulting from exposure to toxic substances.
• 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.
• 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.
• 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.
• Protocols have been established for safety evaluation of foods and substances used in foods
• Acute toxicity • Genetic toxicity• Subchronic• Chronic• Teratogenesis
• 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).
• New approaches to safety evaluation may be required for Genetically modified foods|(GMOs)
• Comparative toxicology concept
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
• 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: TomatineProperties
fairly heat stable ,not decomposed during cooking,not water soluble
• 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
• Goitrogens: components that exhibit adverse effect on the thyroid gland function e.g;– Glucosinolates– Cyanogenic glucosides– Soy factorGlucosinolates are sulphur- containing
glucosideOccurrence: plant family crucifereae of
the genus. E.g Brassica ebbage, Cauliflower flower,