THE OPEN UNIVERSITY OF TANZANIA
FACULTY OF SCIENCE TECHNOLOGY AND ENVIRONMENTAL STUDIES
DEPRATMENT OF FOOD AND NUTRITION
OFD 104: FOOD MICROBIOLOGY & SAFETY (2 units)
INSTRUCTORS:
Prof. JUMANNE R.L. MHOMA & Dr. LEONARD W.T. FWEJA
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Course Aims
This course is designed to give students an understanding of the role of microorganisms in food
processing and preservation; various ways of controlling microorganisms, food fermentations,
relation of microorganisms to food spoilage, food borne illness and intoxication and general food
quality, so that they can produce, handle and supervise such operations in the food industry to
safeguard health of consumers of such foods. Food Microbiology is a must for lecturers and
researchers involved in biological sciences, biotechnology and food industry.
The course is also intended to equip students with knowledge and skills of food safety and health
so that they can produce, handle and supervise such operations in the food industry to safeguard
health of consumers of such foods.
Rationale and course description:
Food microbiology and safety is a scientific discipline describing handling, preparation, and
storage of food in ways that prevent food borne illness. This includes a number of routines that
should be followed to avoid potentially severe health hazards. Food can transmit disease from
person to person as well as serve as a growth medium for bacteria that can cause food poisoning.
Good heath therefore depends very much on the safety of the food we eat and also on the balance
of nutrients that this food contains. Thus the knowledge in food safety is an important aspect for
healthy living.
Learning out comes
On successful completion of this module, the student will be able to demonstrate: 
Capacity to describe trends in modern food microbiology, and be able to offer advice on
microbiological applications related to food industry.
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Ability to conduct research in priority areas of food microbiology and make innovations,
discoveries in the same and related subjects.
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The ability to teach and offer advice in food microbiology and its applications on
everyday life.
Familiarity with factors which influence microbial growth in foods.
Knowledge of the procedures and techniques which are used for the isolation and
enumeration of microorganisms in foods
Knowledge of the methods and principles used for controlling microbial contamination
and for preventing subsequent growth of undesirable microorganisms in raw, processed
foods and for extending the shelf-life of foods.
Knowledge of food borne illness and how to prevent them.
Knowledge of microbiology of drinking water and that of waste treatment.
Be able to critically evaluate the recent developments in the control of food safety
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Have an integrated view of the issues involved in food safety and health
Be able to conduct risk assessment of food safety problems
Demonstrate detailed knowledge of the requirements for compliance with food safety
legislation
Identify sources of food contamination and demonstrate appropriate preventive measures
Demonstrate knowledge of precautionary measures associated with food handling and
preparation
Describe how genetically modified foods are genetically engineered
Explain the pro and cons of genetically engineered foods
COURSE CONTENTS
PART ONE: FOOD MICROBIOLOGY
Lecture 1: The Discovery of the Microbial World
In this lecture students will be able to describe the Scope of food microbiology, Origin of
microorganisms, development of the microscope, microbes and chemical changes and the golden
age of microbiology.
Lecture 2: Functional Anatomy of Prokaryotic and Eukaryotic Cells
In this lecture students will be able to describe the general organization of microbial cells:
eukaryotic cell shape, size and arrangement of bacterial cells, structures external to the cell wall,
structures internal to the cell wall. Prokaryotic cell, flagella and cilia, cell wall, cytoplasm and
organelles.
Lecture 3: Microbial Metabolism
In this lecture students will be able to describe chemical changes brought about by
microorganisms, catabolic and anabolic reactions, enzymes, mechanism of enzymatic action,
factors affecting enzymatic activity, nutritional types among microorganisms, carbohydrate,
lipid, protein catabolism, respiration.
Lecture 4: Diversity of Microbial Habitat
In this lecture students will be able to describe the diversity of habitat of microorganisms.
Microorganisms in the atmosphere. Microorganisms of plants. Microorganisms of animal origin.
Microorganism of soil. Microorganisms of water.
Lecture 5: Growth & Survival of Microorganisms in Food
In this lecture students will be able to describe factors that determine microbial growth in foods:
Extrinsic factors-temperature, humidity and atmospheric gases. Intrinsic factors: nutrient content,
pH, redox potential, water and antimicrobial barriers.
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Lecture 6: Microbiological Examination of Foods
In this lecture students will be able to describe methods for microbiological examination of
foods: direct examination, cultural techniques. Enumeration methods: plate counts and most
probable number counts. Immunological methods and DNA/RNA methodology.
Lecture 7: Microbiology of Primary Food Commodities
In this lecture students will be able to describe microbiology of primary food commodities:
contamination of foods, microbes in dairying, meat, fish, cereals, pulses, nuts and oil seeds, fruits
and vegetables, sugar and sugar products and microbiology of canned foods. For each
commodity describe source of microorganism, types of microorganism naturally present,
spoilage, its safety and their control. Also the role of microorganisms in food production will be
considered.
Lecture 8: Aquatic Microbiology and Sewage Treatment
In this lecture students will be able to describe aquatic microbiology the role of
microorganisms in water quality, sewage disposal and recycling, microbiology of compositing
and biogas.
Lecture 9: Microbiology of Food Preservation
In this lecture students will be able to descry be how methods used for food preserving foods
including processing. For each method they will be able to describe how it works, effect on
microorganism death, inhibition), reference values for processing. The methods include cold
storage, heat processing, reduced water activities, acidification, atmosphere modifications and
addition of chemical preservatives.
Lecture 10: Fermented & Microbial Foods
In this lecture students will appreciate the importance of microbial activity in the food industry
and the different products that result from microbial fermentation.
Introduction, Yeasts, Lactic acid bacteria, examples of fermented foods
Suggested Readings
1. M.R. Adams and M.O. Moss (1995). Food Microbiology. New Age International
Publishers.
2. W.C. Frazier and D.C. (1978). Food Microbiology. McGraw-Hill Book Company.
3. Kathleen Talaro and Arthur Talaro (1999) Foundations in Microbiology. McGraw-Hill
Book Company
4. P. Tauro, K.K. Kapoor and K.S.Yadav. (1986). An Introduction to Microbiology. New
Age International Publishers.
5.
Banwart, George J. (1989). Basic Food Microbiology, 2nd ed. AVI/ Van Nostrand
Reinhold Publishing Co.
6.
Jay, James M. (1996). Modern Food Microbiology, 5th ed. D. van Nostrand Co.
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7. Hackney, C., M.D. Pierson and G. Banwart. (1996). Basic Food Microbiology, 3rd.
Edition.
8. Robinson, R.K. (1981). Dairy Microbiology, Vol. 1and 2. Applied Science Publishers,
London.
PART TWO: FOOD SAFETY
Lecture 11: Introduction to Food safety
This chapter introduces the concept of food safety, food safety issues and the effects of poor and
effective food safety
 Food safety and its importance (Meaning of food safety and food sanitation: The
importance of food safety: Consumer expectation, the impact of illness, benefits of
effective food safety and costs of poor food safety)
 Food safety issues: physical, chemical and microbiological contaminants
 Food safety systems
Lecture 12: Physical and chemical contaminants and additives
This chapter explores the food safety hazards (chemical and physical hazards in particular) and
how they arise and consider how they can be prevented and controlled.
 Metals, minerals soil, engine oil, stones), plant (leaves, twigs, pods and skin), animal (air,
bone, excreta, blood, insects, larvae)
 Safety evaluation of food ingredients
 Major pathways by which chemical residues and contaminants enter the food chain
 Agrochemicals (pesticides) and veterinary drugs, packaging materials, process
equipment and ingredient impurities
 Food additives functions and their consequence to health.
Lecture 13: Natural toxic substances
This chapter examines the naturally occurring toxicants in food and their consequences to health
 Protease inhibitors, haemagglutenins, cyanogens, heavy metals, and nitrosamines
 Natural toxins and toxic mushroom
Lecture 14: Biological Hazards: Bacterial Agents of Food Borne Illness
This lecture will enable students to describe the bacterial agents of food borne diseases, the
factors affecting their emergencies and also differentiate between food infection and food
intoxication
 Bacterial food intoxications & Bacterial food infections.
 Brucella, bacillus cereus, clostridium perfinges, Clostridium botulinum, Escherichia coli,
Salmonela (Covering such aspects like the organism and its characteristics, pathogenesis
and clinical features, and association with foods)
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Lecture 15: Biological Hazards: Non-Bacterial Agents of Food Borne Illness
This lecture examines the other group of biological hazards, the non bacterial agents. At the end
of the lecture students will be able to describe the non-bacterial agents of food borne diseases,
the factors affecting their emergencies and the toxins they produce and the associated effects
 Toxigenic fungi: Mycotoxins of Aspsergillus (The aflatoxins, and Ochratoxins),
Mycotoxins of Penicillium, Mycotoxins of Fusarium (Alimentary Toxic Aleukia, DON
& other Trichothecenes, Zearalenon), Food borne virus (polio, Hepatitis A,
Gastroenteritis Viruses)
Lecture 16: Food Microbiology & Public Health
In this lecture students will realize the significance and risks associated with foodborne illness
and their prevention through controlling contamination and the handling or storage temperatures.
 Factors affecting the emergence of pathogens
 Food hazards, significance of food borne disease, incidences of foodborne disease, risk
factors associated with food borne illness
 High risk foods
 Preventing Food Poisoning – by (i) Contamination Controls (ii) Temperature Controls
Lecture 17: Control of Food safety
In this lecture students will learn about food safety management systems and will be able to
describe the HACCP system and its application along the food chain and its importance in
protecting public health and eliminating health risks
 Good manufacturing practices (GMPs), Hazard Analysis and Critical Control Points
(HACCP), Quality Management Systems
 Meaning, Quality evaluation, steps involved in HACCP, Implementation and problems in
HACCP
 Risk management, assessment and communication
Lecture 18: Genetic Modification Technology and Food safety
At the end of this lecture students will be able to describe the process of genetic modification, the
reasons for genetic modification and the associated risks.
 Methods of genetic modifications
 Genetically modified plants and animals
 Containments: physical and chemical
 GM products
 GM testing and analysis
 Safety evaluation of novel products
 Risks and benefits of GM foods
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Lecture 19: Food safety legislation and Laws
This lecture examines the food regulatory process and the various agencies involved. At the end of the
lecture student will be able to describe the food regulatory process, the role of the various regulatory
agencies and process of development of food specifications and standards
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Introduction
The Food Regulatory Process
Why food laws?
Food Laws: Regulatory bodies and their function
 International Standards Organisation (ISO)
 Codex Alimentarius Commission
 National Standards:
 Tanzania Food and Drug Authority (TFDA)
 Tanzania Bureau of Standards (TBS)
 Meaning of Food specification
 Meaning of Food standards
 Importance of food standards
 Classification of Food standards
 Level of Food standards
Lecture 20: Food Hygiene and Sanitation
This chapter examines the conditions and measures necessary to ensure the safety and
wholesomeness of food.
 Importance of food hygiene and sanitation with relevance to food industry.
 General principles of food hygiene in relation to food preparation, processing,
packaging, storage and transport and personal hygiene.
 Hygiene and sanitation with relevance to the physical structures of the site and building.
 Cleaning & Disinfection: the aims of cleaning, Detergents, disinfection (hot water, steam
& chemical disinfectants), sanitizers, safety precautions.
Suggested Readings:
1.
2.
3.
4.
Schmidt, R. H & Rodrick, G. E (2003) Food Safety handbook. John Wiley & Sons Inc.
Jones, J. M (1992). Food Safety. AACC. Paul, Minn, USA
Altug, T (2002). Introduction to Toxicology and Food. CRC Press
Brown, M and Stringer, M, (Eds) (2002). Microbiological Risk Management in Food
Processing. Woodhead Publishing Limited
5. Food Toxicology. (2002) Edited by Helferich, W and Winter, C. K, CRC Press LLC
6. IFST (1998) Good Manufacturing Practice: a guide to its responsible management. Fourth
Edition, Institute of Food Science and Technology, UK
7. Mitchel, R.T (2000). Practical Microbiological Risk Analysis. Chandos Publishing (Oxford)
Limited
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8. Mitchel, T.J., Godfree, A. F. and Stewart-Tull, D.E.S, (Eds) (1998). Society for Applied
Bacteriology Symposium Series Number 27
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