Food Safety management

1. 9/8/2023 1
Haramaya University
College of Health and Medical Science
Food Safety Management
By: Dechasa Adare (MSc.)
2022/23 Ac. year
dechasaadare@gmail.com

2. Introduction
• Food consists of edible materials such as meat, bread and
vegetables; it may be or cooked, processed or semi-processed.
• Food is a nutritious substance eaten by us to maintain our vital life
processes.
• It is a fundamental need, a basic right and a prerequisite to good
health.
• Food is a major determinant of health, nutritional status and
productivity of the population
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3. • People are becoming increasingly concerned about the health risks
posed by microbial pathogens and potentially hazardous chemicals
in food.
• Ready-to-eat foods sold by public food vendors contribute
significantly to food insecurity
• About one-third of the populations of developed countries are
affected by food-borne illness each year (WHO)
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4. • The problem is likely to be even more widespread in
developing countries
• The occurrence of foodborne disease remains a significant
health issue
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5. Food Safety Management
Elements of Food Safety Management
Government
Industry
Consumers and the Informal Sector
Academia
Challenges in Management of Food Safety
 To ensure the safety of its products
 To meet consumers’ expectations in terms of quality
 Managing food safety is by itself very complex (subject (food, MOs
etc), operation, supply, environment and Human factors
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6. Food safety: facts and figures
A global problem
• Every day, in every country, people fall ill from the food they have
eaten.
– These foodborne illnesses are caused by dangerous micro-
organisms and/or toxic chemicals
• The WHO has estimated that 1.8 million people die each year from
diarrhoeal diseases
– Most cases can be attributed to contaminated food or drinking
water.
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7. • The cost in human suffering is thus far too high,
– In particular, for the most vulnerable population groups
(infants and young children, pregnant women, the elderly,
the ill, etc.).
• Malnutrition, coupled with diarrhea caused by unsanitary food
– Primary cause of child mortality
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8. The WHO has also recognised that foodborne illnesses:
Are a problem in developing and developed countries
Place a burden on healthcare systems
Seriously affect infants, young children, the elderly and those
who are already ill
Spawn a vicious circle of diarrhoea and malnutrition
Undermine the economy and national development efforts, as
well as international trade.
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9. Food Hygiene includes:
The consumption of food
The prevention of food poisoning
Personal hygiene
Training
Pest control
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Food preparation practice
Cleaning system
Refrigerating and heating
Waste handling
etc.

10. Food safety: key concepts
‘Hazard' & 'risk‘
• Hazard: a physical or biological agent or substance with the potential to
cause an adverse effect on health.
• Risk: Probability of an adverse health effect of hazards.
 The degree of risk is a combination of the probability and the severity
of the effect:-
 Type of hazards
 Number of people affected
 Vulnerable group
 etc.
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11. • Food Hygiene: all sanitary measures, principles and procedures put
in place to ensure that food is free from agents of contamination or
disease germs.
– All measures necessary for ensuring the safety, wholesomeness,
and soundness of food at all stages
• Food safety: The process of handling, preparation and storage of
food in ways that prevent food-borne infection/illness.
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12. • Food safety and quality are important at:-
 Home level
 Large scale food production and processing
 Where the food is freshly prepared and served
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13. Hygiene and Cold Chain
• Many of the hazards attributed to food originate in the failure to
respect hygiene rules through out food chain.
– Because, hygiene is an essential requirement for the conformity
of the products
• Therefore, following the basic principles of hygiene considerably
reduces risks of food contamination.
– Preservation conditions during storage and transport also have a
considerable impact on food quality.
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14.  Failure to keep food at the right temperature and relative
humidity can lead to:-
 Food spoilage
 Favour the development of pathogenic micro-organisms
Therefore, the 'cold chain‘ must be respected absolutely!
 The optimal temperature and relative humidity of storage must be
known for each product
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15. Product
Product' is the result of production, in other words a coherent sequence of
operations.
– are all foods of plant or animal origin that a producer places on the
market.
• Each type of food product is associated with different types of risks due to
their:
 Nature (origin, composition, sensitivity);
 Production mode;
 Preservation mode;
 Mode of preparation and consumption (raw or cooked).
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Therefore, it is important for the producer to be fully
aware of the characteristics of the:-
 products
 processes in order to evaluate the risks.

17. Food chain
 Ensuring food safety must be a goal for all 'actors/stakeholders' along
the food chain.
 An approach that focuses on the food chain to manage food safety
and quality recognises that:-
– All actors are responsible to provide a safe, healthy and nutritious
food.
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18. The food chain
Materials &
Equipment
Cash
Cash
Cash
Cash
Cash
Cash
Food
Animals
Crops
Material & Energy inputs Land Food processing and
distribution Consumer System
Banking System
Ancillary Industries
Cash Flow
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19. Food poisoning
• Food poisoning is an illness that occurs usually between 1 and 36
hours after eating contaminated or poisoned food
– The most common symptoms include diarrhoea, vomiting and
dehydration
• Toxins: are poisonous chemicals produced by certain types of
bacteria or living things, e.g. Staphylococcus aureus produces a
toxin.
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20. Minimally processed foods
• These are processed as little as possible in order to retain the quality
of fresh foods.
• It involves cleaning, trimming, shelling, cutting, slicing and storage
at a low temperatures.
Formulated foods
• These are products prepared by mixing and processing of individual
ingredients to result in relatively shelf-stable food products such as
bread, biscuits, ice cream, cakes etc.
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21. Food derivatives
• The components of foods may be obtained from the raw product
through purification,
– e.g., sugar from sugarcane or oil from oil seeds.
Medical foods
• These are foods used in dietary management of diseases
– e.g. low sodium salt, lactose–free milk for persons with lactose
intolerance.
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22. Food Borne Infections
• Result when a person consumes food containing pathogens; which
grow in the human intestine
Food Borne Intoxications
• Result when a person consumes food containing toxins produced by
the microorganism
– Typical symptoms of a ‘food borne intoxication’ appear quickly.
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23. Food hazards
• Food hazard: is any food that is contaminated with biological,
chemical or physical agents and, if eaten, will cause ill health.
• The hazards can arise from:-
Improper agricultural practices
Polluted environment (mercury, cadmium, nickel)
Poor hygiene at any stage of food chain (E.coli, Listeria,
Campylobacter)
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24. Lack of preventive controls in food processing and preparation
operations
Misuse of chemicals (pesticides, weed inhibitors, growth
hormones)
Contaminated raw materials, ingredients and water (bacteria,
viruses, and mycotoxins)
 Inadequate or improper storage or handling
Adulterated food
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25. Types of food safety hazards
• Chemical hazards include cleaning supplies
• Physical hazards
– Foreign objects, like dirt, hair and glass.
• Biological hazards
– Microorganisms such as, bacteria, viruses and parasites –.
– These are the greatest threat to food safety,
– Responsible for the majority of food borne illness outbreaks
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28. Contamination
• It is the presence of harmful, or objectionable foreign substances in food
such as chemicals, micro-organisms, dilutants before/during or after
processing or storage
• Sterilization
– Refers to any process that eliminates, removes, kills, or deactivates all
forms of life and other biological agents
• Sanitation
– Is the creation and maintenance of hygienic and healthful
conditions”
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29. Perishable food
• Food items that have a short storage life and will become spoiled or
contaminated if not preserved and handled properly,
– e.g. meat, eggs, milk, fruits, vegetables and the like.
Non-perishable food
• Foods which are not easily spoiled or contaminated,
– e.g. sugar and cereals.
• Wholesome food
– Food which is sound, clean and free from harmful ingredients
– It is suitable for human consumption.
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30. Adulterated food
• Is food contains any substance other than its genuine components or
not available in its natural state
Stable foods
• Are foods that are not easily spoiled
– e.g. dry beans.
Misbrand
• Is the presence of any label or writing printed which:-
– Is false, misleading to the user or violets labeling requirements.
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31. Importance of food
• Food is essential for the existence of all living things.
• Our bodies need food for energy production, to survive and to
remain strong.
• For good health we need a balanced diet
– Balanced diet rich in:-
• Protein,
• Energy and
• Vitamins
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32. Food is
essential
for:
For growth and maintenance
To keep physiological process working
To keep the body temperature constant
To provide energy
To maintain proper health
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33. However:-
• Any kind of arrangements for growing, processing, preserving,
packaging, storing and distribution of foods have many impacts
on the
– Safety
– Nutritional value
– Wholesomeness
– Palatability of food
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34. The three basic principles for food hygiene and safety can be
summarized in to essential activities:
1. Prevention of contamination
2. Elimination / destruction of pathogenic microorganisms
3. Prevention of the growth/ inhibition of toxin
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35. • Contamination of food can be
either:-
– Chemicals
• Pesticides
• Cleaning,
• detergents, etc.
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• Biological agents:
 Bacteria
 Viruses
 Parasites
 Helminthes
 Protozoa etc.
Food contamination

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Food can be contaminated in the chain of its production &
distribution
Chain of food contamination

37. Food Microbiology
• Food Microbiology is the study of the microorganisms that:-
– Inhabit, create or contaminate food and cause food spoilage.
• It explores the fundamental elements that affect:-
– The presence
– activity, and
– Control of microorganisms in food.
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38. • It include:-
Minimum standards and principles that affect microorganisms in
food
Production of food, beverages, cheese, yogurt, beer, wine, etc.
with the use of microbes
Detection and prevention of food-borne diseases and food
spoilage
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39. Food microbiology involves four major components:
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Foods
Environment (Immune
response)
Host Health
Processing
Microorganisms
Fermentation or
spoilage
Substrate and
Environment
(Pathogens or
probiotics)
Stress
Safety and quality
Safety and quality

40. • Microbes have special qualities which enable them to survive in
such unique places as the
 Soil, oceans, streams, ice, water pipes, concrete, hot springs,
human intestine, root of plants, foods etc.
 Omnipresent
 Characterized by very high degree of adaptability
 Has full of uniqueness from different biological standpoints.
 Spread over the entire biosphere: the lithosphere, the
hydrosphere and the atmosphere.
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41. • Microorganisms are important in many different ways:
 Pathogenic, or disease causing, microorganisms can cause
illness
 Spoilage microorganisms cause a food to smell, taste, and
unacceptable
 Fermentation microorganisms produce a desired food product
 Other microorganisms do nothing in foods
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42. • The key role of microbes in nature is:-
 Decomposition of complex organic materials into simpler compounds/
atoms, then made them readily available for reuse by all other life
forms
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43. Microbiology is subdivided into a number of diverse fields:
 Bacteriology-the study of bacteria
 Virology -the study of viruses
 Protozoology -the study of protozoans
 Phycology-the study of algae, and
 Mycology-the study of fungi
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44. Bacteria
Bacteria can be classified in a number of ways.
Shape: Round=cocci or Elongated=rods
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45. Categories of Microbes Based on Temperature Range
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47. Based on oxygen requirements:-
• Aerobic -Need oxygen to grow
• Anaerobic -Can grow only if oxygen is absent
• Facultative - Can grow with or without oxygen.
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48. Reproduction of Bacterial Cells
• Reproduced by division
– Under optimum conditions a cell divides every 20-30 minutes
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49. Temperature and growth
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 Psychrophile: Grow from 1-20oc
e.g. pseudomonas, flavobacterium, alcaligenes
 Psychrotrophic: Grow best at 37oc
e.g. listeria monocytogenes
Mesophile: Optimum temperature 20-40oc
 Group containing most human pathogens
e.g. Coli, salmonella, clostridium botulinum
 Thermophile: Optimum temp >45oc
 e.g: bacillus stearothermophilus

50. Growth of Bacteria
• Binary Fission
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51. 9/8/2023 51

52. The growth cycle of bacteria can be expressed by a growth curve:
• When bacteria are inoculated into an ideal culture medium (in
the lab.) the pattern of the growth curve exhibits four distinct
phases; namely
– The lag phase
– The log (logarithmic) phase
– The stationary phase
– The decline phase
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53. 9/8/2023 53

54. Bacterial growth curve
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55. The lag phase:
 Period of acclimatization/ simply a phase of adjustment to new
environment.
 No significant increase in number of organisms
 Can be extended with less microbial proliferation through reduced T0
 Improved sanitation (low range of initial contamination) also extends
the lag phase
 High initial contamination would decrease the lag phase and increase
bacterial proliferation
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56. The log (logarithmic) phase:
– After the lag phase
– Optimum environment favoring maximum rate of reproduction
and growth
– The growth curve is a straight line.
– Rate of growth is in geometric progression/Exponential
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57. The stationary phase
• In this phase available food supply declines due to maximum use by
the ever increasing bacterial population.
• The growth of new cells becomes relatively stable.
– Dying # relatively equals to the # of new cell.
– Therefore, total bacterial population remains more or less
constant.
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58. The decline phase
• In this phase most of the bacteria start dying mainly due to:
– Depletion of food supply.
– Accumulation of bacterial metabolic wastes in the environment;
becomes toxic to the bacteria
– Competition among the bacterial population for the dwindling
food supply.
– In case of food stuffs; the type of food and other environmental
conditions like T0, moisture content etc. are the limiting factors.
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59. Quiz (10 pts)
1. What is major aims of food safety management ? (2pts)
2. Briefly describe the phases of bacterial growth (3pts)
3. What is danger zone? (2pts)
4. What are the public health implication of food hygiene and
safety?(3pts)
Time given: 15 minutes
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60. What Bacteria Need to Grow ?
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F
Food
2-10
A
Acidity
T
Temperature
T
Time
O
Oxygen
M
Moisture

61. • Infectious disease
• Decay
• Pollution
• Photosynthesis and Nitrogen
fixation
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• Foods
• Antibiotics
• Scientific inquiry
• Molecular biology
• Immunology
Importance of MOs in human affairs

62. Decay
• Reduces complex organic chemicals to
inorganic compounds:
– Cellulose
– DNA and RNA
– Lipids
– Proteins
– Starches
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Pollution
• Eutrophication
Algal blooms remove oxygen from
water
• Bioremediation
Microbes are used to clean up
pollution (e.g sea shore pollution by
oil spills).

63. Photosynthesis and Nitrogen fixation
• Converts Carbon-dioxide to organic
carbon compounds
• Production of oxygen
• Bottom of food chain
• Converts nitrogen to usable nitrogen-
containing compounds
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Foods
• Bread
• Cheese
• Milk products
• Alcoholic beverages
• Spoilage and preservatives

64. Antibiotics
• Penicillin
• Tetracycline
• Erythromycin
• Bacitracin
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Scientific inquiry
• We study MOs because of their similarity to
other organisms
• Biochemically, all cells are similar ( from
bacteria to humans).
• MOs are much easier to work with
• Used as an indicator organisms (E.coli, or
coliform bacteria)

65. Molecular biology
– Gene cloning (a process of creating an exact copy of a single
gene, cell or organism).
– Genetic engineering
– Human genome project
Immunology
– Disease prevention (vaccines)
– Diagnosis
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66. Food processing
• Why we process foods?
– Safety
– Nutritional reasons
– Improve storage (shelf) life
– Improve flavours, colour, texture etc.
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67. Food processing operations
– Ambient temperature processes
– Mechanical processes
– High temperature processes
– Low temperature processes
– Fermentation processes
– Post processing
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68. Ambient temperature processes
• Include:-
– Cleaning and sorting
– Peeling, shredding, chopping and milling
– Mixing, blending and forming
• Are often preparation processes for subsequent operations.
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69. Physical Separations
• Include:-
– Filtration, centrifuging,
– Expression and extraction
– Membrane separations
• These often involve recovering a particular component from a raw
material
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70. High temperature processes
• Two major purposes
– Safety; pasteurisation and sterilisation
– Cooking; modifies flavour, texture, nutritional qualities.
• A single process may serve both functions simultaneously.
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71. High temperature processes include
– Sterilisation and pasteurisation
– Blanching
– Baking & Roasting
– Frying
– Microwave and infra-red heating
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72. Blanching
• Purpose: As a pre-treatment, especially for
– Dehydration
– Sterilisation
– Freezing
• Heat is sufficient to inactivate enzymes but not to cook
– Under processing is as bad as over processing
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73. Baking and Roasting
– Baking usually refers to dough products
– Roasting usually:- meat, & vegetables.
– Surface undergoes chemical changes developing colour and
flavour
• The heat has nutritional effects
– Food easier to eat and digest
– loss of vitamins
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74. Frying
– Frying is cooking in hot oil
– Its purpose is to improve eating quality of the food
(flavour, texture)
– Effects of frying are similar to those of baking
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75. Microwave and infra red heating
• Microwave and infra red heating use electromagnetic radiation.
• It involves short wavelength radiation.
• The energy is dependant on
– Temperature
– Surface properties
– Shape of the bodies
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76. Processing at low temperatures
– Low temperature slows the rate of microbial growth, but does
not kill microbes
– Up to a point, the lower the temperature, the longer the shelf life
– Below -10 oC, all microbial growth stops, but some residual
enzyme activity may remain
– The main function of chilling and freezing, therefore, is for
storage and prolonged shelf life.
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77. Fermentation
• Fermentation serves a number of
purposes, including;
– Preservation
– Improve nutritional quality
– Health Benefits
There is a wide variety of fermented
foods including
• Dairy products
• Fermented Meat and vegetables
• Beverages
• Bread, etc.
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78. Post processing operations
• These include packaging and storage.
• Purposes include
– Protection
– Increase storage life.
• Increasingly modified atmospheres are being used to increase shelf
life.
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79. Five keys to safe food
• Germs are carried on hands, wiping cloths and utensils, especially
cutting boards, and surfaces like door handles.
• Even the slightest contact can transfer them to food and cause
foodborne diseases.
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80. 1. Keep clean
• Wash your hands before handling food and often during food preparation.
• Wash your hands when they are exposed to germs
• Wash, and sanitize all surfaces and equipment used for food preparation
• Protect kitchen areas and food from insects, pests and other animals.
• Keep food covered, in closed containers or refrigerated.
• Keep food preparation area clean and in good condition.
• Keep clean and remove rubbish daily
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81. 2. Separate raw and cooked
• Separate raw meat, poultry and seafood from other foods at all
stages from cleaning, storing, preparation, and cooking.
• Use separate equipment, and utensils for handling different types of
foods; meats, poultry, sea foods and etc.
• Store foods in covered containers to avoid cross-contamination
between raw and prepared foods.
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82. 3. Cook thoroughly
• Ensure food is thoroughly cooked through, especially meat, poultry,
eggs and seafood.
• Microorganisms can multiply very quickly if food is stored at room
temperature.
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83. 4. Store food at safe temperatures
 Do not leave cooked food at room temperatures for
more than 2 hours.
 Refrigerate all cooked and perishable foods
promptly
 Keep cooked food very hot (above 60°C) prior to
serving
 Do not store food too long (more than 3 days) in the
refrigerator
 Do not reheat refrigerator food more than once
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84. 5. Use safe water and raw materials.
• Use safe water or treat it (by boiling, chlorination, and filtration) to
make it safe
• Select fresh and wholesome foods (not damaged or rotting) from
clean stores / places
• Wash fruits and vegetables, especially if eaten raw
• Do not use food beyond their expiry date
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85. 9/8/2023 85
In general, food safety management demands:-

86. Food Safety in Ethiopia
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Stakeholders
involved in food
safety
management
Ministry of
health
Ministry of
agriculture
Quality and
standards
authority of
Ethiopia
Environmental
protection
authority
Ministry of
industry
Ministry of
trade
Research
institutions
Ministry of
education
FMHACA
Federal and
Regional
Governmental
Bodies
Food
Manufacturers
Food
distributors
and hotels

87. • There is a gap in food safety system in Ethiopia such as:-
– Legal and policy frame work
– Food-borne diseases surveillance
– Coordination of organizations involved in food safety
management
– Laboratory services for relevant food hazards
 Obstacles to economic development and public health safety
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88. Food safety in Ethiopia: Situational analysis
• Both food shortage and lack of appropriate food safety
assurance systems are problems that have be-come obstacles
to:
– The economic development and
– Public health safety
• Its competitiveness in the world market has been so far very
low
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89. Food-borne diseases in Ethiopia
• According to patient morbidity statistics the annual incidence
of food-borne illnesses ranged from 3.4 to 9.3%,
• Deaths associated with diarrhea alone ranged from 22.6 to
62%.
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90. The role of standards, laws and regulations in ensuring food
safety
• There is little information about laws and regulations concerning
food safety in Ethiopia.
• Some provisions were given under different regulations
• The FDRE issued its first proclamation that contained the
surveillance of foodstuff and
• United Nations Industrial Development Organization (UNIDO) is
making efforts to implement ISO 9000 and the HACCP system
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91. Codex and food safety system in Ethiopia
• The National Codex Committee was established under Quality and
Standards Authority of Ethiopia
– Identify priority areas on food safety
– Develop fundable projects
– Conduct national awareness program on food safety and
standards
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92. Role of government, producers, manufacturers, retailers and consumers
in food safety management
• Producers are the first who need to apply these hygiene rules.
• Hygiene rules also concern exporters, wholesalers, transport
operators, distributors (food chain)
• Consumer is also responsible for ensuring food safety
– Present any danger of food poisoning
– Handling and storing food in proper hygienic conditions
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93. • However, as the result of lack of resources or qualifications:-
– Small producers are often unaware of or inadequately evaluate the
risks
– Certain sources of contamination cannot be kept totally under control
– It is possible for operators to limit risks during production and
packing by applying a set of measures.
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94. Responsibilities of the Food Handler
Use only approved ingredients
Do not make decisions which can affect food integrity or safety
Understand your responsibilities
Understand and do the job as trained
Avoid cross-contamination
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95. Wash hands thoroughly after handling known allergens
Wash hands thoroughly after eating
Keep aprons and cloth clean
Follow a appropriate sanitation program
Keep all ingredients closed when not in use
Use only specified equipment and utensils
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96. Assignment( 6pts)
1. Briefly describe all steps of hand washing recommended
by WHO and CDC
2. Explain dishwashing process
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97. Consumers Responsibility
 Report non conformities in labelling
 Educate family and consumers
 Be aware of pitfalls
 Make decisions based on reliable information
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98. Food spoilage or rotting is any change that causes the food to lose its
desired quality and to make it unfit for consumption
– It may be due to a natural process that begins when the
biological cycle is interrupted by harvesting
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 Food spoilage

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100. 9/8/2023 100

101. • Some foods are prone to faster spoilage by MOs
– Foods that spoil fast are usually referred to as “high risk foods.
– Mostly they are ready to eat foods or rich protein
– Examples of these foods are:
Cooked meat, meat products or poultry
Milk and its products
Eggs and made from raw eggs
Cooked fish
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102. • Food that is spoilt can be identified in different ways:
 Odours: Foods tend to develop undesirable oflavours and/or odours
 Discolouration: changes in colour
 Unusual taste: changes in taste
 Production of gas: especially when stored in sealed containers
 Mould growth: e.g. bread develop fungi
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103. • Physical deterioration is caused first and foremost by
dehydration
• Physiological ageing occurs as soon as the biological
cycle is interrupted by the harvest
• Food spoilage may be caused by micro-organisms
• Chemical spoilage: as the result of oxidation of the fat
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105. 9/8/2023 105
Relative humidity
Rancidity is development of unpleasant smells in fat and oil that are
related with the change in texture and appearance

106.  Rancidity is development of unpleasant smells in fat and oil that are
related with the change in texture and appearance
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107. Microbial Food spoilage
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108. Factors affecting spoilage microorganisms
• Initial microbial load
• Intrinsic factors
(e.g. Water activity and moisture content, etc)–
• Extrinsic factors affecting microbial growth
– e.g. temperature, preservatives, etc
9/8/2023 108

109. 9/8/2023 109

110. Spoilage process
Several events need to take place in sequence
Microbes need to access the products from one or more
The food environment should support the growth of the contaminant
microbes
The temperature must be suitable for the microbial growth
The product must be stored under the favorable condition
9/8/2023 110

111. 9/8/2023 111

112. 9/8/2023 112

113. Preservation techniques
 Food preservation is the process of treating and handling food in such a
way as:-
 To stop or slow down its spoilage
 To prevent food borne illness
 To maintaining nutritional value, texture and flavor
 To preserve foods, sometimes it is necessary to change the environment of
MOs
9/8/2023 113

114.  Drying
 Drying is one of the oldest preservation methods.
 The moisture content of products decreases to 10 to 15 %
Prevents micro-organisms from multiplying and neutralizes
enzymes
9/8/2023 114

115. • Freezing is also one of the most commonly used processes
commercially and domestically
• Long-term storage for strategic food stocks
Vacuum packing
• Vacuum-packing: stores food in a vacuum environment, usually in an
air-tight bag or bottle.
• The vacuum environment strips bacteria of oxygen needed for survival,
slowing spoiling.
9/8/2023 115
Freezing

116.  Salting or curing draws moisture from the meat through a process
of osmosis.
 Meat is cured with salt or sugar, or a combination of the two.
 Nitrates and nitrites are also often used to cure meat
 Inhibition of Clostridium botulinum.
 It was a main way of preservation in the medieval times.
9/8/2023 116
Salting

117. Smoking
 Smoking is used to lengthen the shelf life of perishable food items.
 This effect is achieved by exposing the food to smoke from burning
plant materials such as wood.
 Most commonly subjected to this method of food preservation are meats
and fish
9/8/2023 117

118. 9/8/2023 118
 Preservative food additives can be antimicrobial
• Which inhibit the growth of bacteria or fungi
 Common antimicrobial preservatives include:-
 Calcium propionate
 Sodium nitrate
 Sodium nitrite
 Sulfites etc,
Artificial food additives

119.  Pickling is a method of preserving food in an edible anti microbial liquid.
 Pickling can be broadly categorized into two categories:
1. Chemical pickling
2. Fermentation pickling.
 In chemical pickling, the food is placed in an edible liquid that inhibits or kills
bacteria and other micro-organisms.
 High in salt, vinegar, alcohol, and vegetable oil
 Many chemical pickling processes also involve heating or
 Common chemically pickled
 In fermentation pickling, the food itself produces the preservation agent, typically
by a process that produces lactic acid.
9/8/2023 119
Pickling

120. Canning and bottling
 Canning involves cooking food, sealing it in sterile cans or jars,
 High-acid fruits like strawberries require no preservatives to
can and only a short boiling cycle
 Low acid foods, such as vegetables and meats require pressure
canning.
 Food preserved by canning or bottling is at immediate risk of
spoilage once the can or bottle has been opened
9/8/2023 120

121. Methods of heat treatment:
• Low-heat (less than 100 degrees): Pasteurization
• Microwaves: hot but problematic
• High heat (greater than 100 degree centigrade)
• Low acid: 12D to kill C. botulinum spores
• Other spores can survive, but won’t germinate below 30
degrees.
• High acid: dangerous spore formers don’t grow
• UHT will kill microbes, but may not destroy enzymes or
toxins
9/8/2023 121

122. D Value
• In microbiology, D-value refers to decimal reduction time
and is the time required at a certain temperature to kill 90%
of the organisms being studied.
• Thermal death time (TDT): complete killing will be longer
for spores than vegetative cells
• “12D” process for canning high-pH foods
9/8/2023 122

123. Gamma-(γ)-Irradiation :
 Microbicidal against a wide variety of microbes
 This type of radiation is focused and penetrating
 Can damage DNA and correlated to the dose
 Can penetrate food packaging
 Molds>yeasts>bacteria>viruses in sensitivity
 Toxins are not destroyed
9/8/2023 123

124. Irradiation
Irradiation of food is the exposure of food to ionizing radiation;
Either high-energy electrons or
X-rays from accelerators gamma rays (emitted from
radioactive sources such as Cobalt-60 or Caesium-137).
It can kill the bacteria, molds, and insect pests or
Reduce spoiling of food,
At higher doses inducing sterility.
9/8/2023 124

125.  Neither the workers in such facility nor the environment receives any
radiation dose from the facility.
 Irradiation may allow lower-quality or contaminated foodstuffs to be
rendered marketable.
 It is estimated that about 500,000 tons of food items are irradiated per
year worldwide in over 40 countries.
9/8/2023 125

126. Group Assignment and Presentation (15%)
• Ohmic heating, and high pressure processing, in food processing and
preservation: Group 1
• Pulsed light technology and Pulsed electric field in food processing and
preservation: Group 2
• Milk and product, egg and its product hygiene and safety: Group 3
• Fish and its product and meat and its hygiene and safety : Group 4
• Good slaughter house features Group 5
• Priority setting, and ethics in food safety Group 6
9/8/2023 126

127. Food Safety Strategies
9/8/2023 127

128. Good Manufacturing Practices
9/8/2023 128

129. Good Manufacturing Practices
 Deal with contamination
By people
By food materials
By packaging materials
By hazardous materials
By miscellaneous materials
9/8/2023 129

130. Hygiene
 All employees working in direct contact with food.
 Food contact surfaces and food packaging must conform to
hygienic practices.
 This aimed against food contamination by microorganisms or
unwanted materials.
 The best way to avoid contamination is to prevent it
9/8/2023 130

131. How do we prevent contamination?
9/8/2023 131

132. Production’s employees
• Bathe daily
• No perfume or fragrant creams
• No jewellery
• No false nails or nail polish
• Fingernails should be trimmed short
• No eating, drinking or chewing gum
9/8/2023 132

133. Clothing
• Everyone must wear appropriate cloths.
• Separate shoes (no open or high heels) are to be worn
• Personal clothing must be stored in locker rooms.
9/8/2023 133

134. Illness or health condition
• Health certificate
• Inform your supervisor if you are ill with symptoms that could
contaminate ingredients or products
• No medication allowed in factory
• Ensure that a clean bandage covers any open wounds
9/8/2023 134

135. Hand washing
All employees must wash their hands thoroughly:
 When they enter food handling areas
 Before starting work
 After handling contaminated materials
 After breaks
 After using toilet facilities
 etc..
9/8/2023 135

136. Personnel
– Do not leave gloves, masks, etc.
– Boxes, containers or buckets must not be placed directly on the floor.
Food Handling Practices
9/8/2023 136

137. Product
• Keep hand contact with ingredients to a minimum
• Check ingredients for expiration dates to ensure that fresh
ingredients are used.
• Cooling product should always be kept covered.
9/8/2023 137

138. Containers
• Ensure that all containers, including those holding rework,
are properly labelled and are kept covered.
Cloths
• Use white cloths to wipe hands regularly
• Dispose of soiled cloths immediately.
• No moist cloths are to be left in the production area
9/8/2023 138

139. Utensils
• Production equipment/utensils must be thoroughly cleaned and
sanitized with alcohol after use
Premises
• Keep unscreened doors and windows closed
• Report any pests such as flies, insects, mice droppings
9/8/2023 139

140. Equipment
• Return tools and attachments to their proper place after use.
• Check product surfaces before starting equipment.
• Remove any foreign objects or dirt.
9/8/2023 140

141. Personnel Practices
• Do not lean, sit or step on product surfaces
• Do not handle ingredients or products with either cut or infected
hands
• Keep hand contact with ingredients and product to a minimum
9/8/2023 141

142. Sanitation
• Keep contact surfaces clean and free of contamination
• Clean all spills promptly
• Work areas should be cleaned regularly throughout the shift
• Keep your immediate working area swept
• Wipe spilled liquids promptly
• Scrape the floor around the work area after completing a job
• Leave your work area clean at the end of your shift
9/8/2023 142

143. Receiving and Storage
• Ensure that all pallets and materials are kept at least 15 cm away
from the walls
• Inspect torn bags and boxes and then repair if appropriate
• Brush off bags and boxes before opening them
• Store ingredients and products at the appropriate temperature
9/8/2023 143

144. • Use ingredients in the proper rotation (oldest stock first)
• Handle ingredients or products carefully to avoid spilling
• Do not return products or ingredients to the production line
after they have touched the floor or any other surface that is
not clean.
9/8/2023 144

145. Maintenance and Repairs
• Any thing needs maintenance should be maintained or
repaired accordingly.
• Do not leave maintenance supplies in the product zone
• Return all tools and attachments to their proper place after use
• Ensure the production area is clear of all tools and hazards
before production starts
9/8/2023 145

146. Retail store
• Monitor and maintain proper temperatures
• Rotate ingredients using FIFO and check for expired items
• Check best before dates and the quality of the food before using
• Refrigerate cold foods immediately upon receipt
• Sanitize equipment, cutting boards, work surfaces and utensils
• Always wash hands after handling money
9/8/2023 146

147. Visitors to Production Areas
• Must be appropriately dressed - hair coverings, booties
over street shoes, gloves, sleeve covers, etc.
9/8/2023 147

148. Food Safety Management Systems -
HACCP
9/8/2023 148

149. 9/8/2023 149
HACCP
Hazard Analysis at Critical Control Point
• A food safety management system which identifies and controls
hazards which are significant for food safety
Food safety management system
• The policies, practices and documentation that ensure the food
is safe to eat.
HACCP Plan
• The written document which is based upon the principles of
HACCP and which delineates the procedures to be followed

150. 9/8/2023 150
Food business operators to implement a food safety management system
based on HACCP principles:
a) Identify hazards
b) Identify critical control points (CCPs)
c) Establish critical limits
d) Implement monitoring at CCPs
e) Establish corrective actions
f) Establish verification procedures
g) Establish documentation
h) Review if changes

151. 9/8/2023 151
Principles of HACCP
1. Conduct a hazard analysis
2. Determine critical control points
3. Establish critical limits
4. Establish monitoring procedures
5. Establish corrective actions
6. Establish procedures for verification and review of HACCP plan
7. Establish record keeping & documentation

152. 9/8/2023 152
12: Steps of HACCP
Step1: The HACCP team
Step 2: Describe the product
Step 3: Identify intended use
Step 4: Process flow diagram
Step 5: Verify flow diagram
Step 6:Conduct a hazard analysis

153. 9/8/2023 153
Step 7: Determine critical control points
Step 8: Establish critical limits
Step 9: Establish monitoring procedures
Step 10: Establish corrective actions
Step 11: Establish procedures for verification and review of
HACCP plan
Step 12: Establish record keeping & documentation

154. Prerequisite programmes
• Are the good hygiene practices a business must have in place before
implementing HACCP
• Prerequisite programmes ensure the HACCP plan concentrates on
the most significant hazards.
9/8/2023 154
What are prerequisite programmes?

155. 9/8/2023 155
Prerequisites for HACCP
Prerequisite programmes
• Cleaning and disinfection
• Pest management
• Good housekeeping
• Waste management
• Labelling
• Contingency plan
• Approved suppliers
• Good design
• Equipment calibration
• Preventive maintenance
• Personal hygiene/competency
• Stock rotation

156. Principle 1
Conduct a hazard analysis
9/8/2023 156

157. 9/8/2023 157
Scope of HACCP plan
• What products are to be included in the plan
• Where will the plan start and end?
• Which classes of hazards are to be included?

158. 9/8/2023 158
Step 1 - The HACCP team
• Multi – disciplinary
• Inter – hierarchical
• Different levels of personnel
• Workable size – usually 4 – 6
• Expertise needed from – technical/microbial, production,
maintenance, purchasing, development, distribution, service

159. 9/8/2023 159
Step 2: Product description
• Ingredients and formulation
• Raw materials
• Storage conditions
• Processing conditions
• Packaging
• Shelf life
• Consumer instructions
• Distribution methods
• Microbiological data
• Physical/chemical parameters
(e.G. Ph, aw)

160. 9/8/2023 160
Step 3: Intended use
• Will the product be consumed by any vulnerable groups?
• What is its shelf life?
• Will it need to be refrigerated, frozen or can it be stored at ambient
temperatures?
• Are there any special requirements?

161. 9/8/2023 161
Step 4 – The process flow diagram
Consider:
• Raw materials – list separately
• Don’t forget:
• Packaging
• Water/air
• Rework
• Transfer stages
A flow diagram
Is a pictorial representation of the steps involved in a particular
process

162. 9/8/2023 162
Delivery and unloading
Storage (chilled)
Preparation
Cooking
Slicing
Cooling
Service (hot) Storage (chilled) Reheating
Service (Hot)
Service (Cold)
• Validate (audit) the
process flow chart.
• Is it right for every
occasion
HACCP flow diagram for cooking a fresh chicken and serving hot, cold or reheating

163. 9/8/2023 163
Step 5 - On site confirmation
• Accuracy is essential as the process flow diagram forms the basis
of the HACCP plan
• “Walk the line” to confirm detail
• Usually carried out by someone not involved in the design
• Carries out at different times/shifts
• Amend where necessary, record changes

164. Step 6 - Hazard analysis
• The process of collecting & evaluating information on hazards
& conditions leading to their presence, to decide which are
significant for food safety & should be addressed in the
HACCP plan.
9/8/2023 164

165. Identify the hazards (Principle 1)
(Micro) biological (C M S )
• Foodborne illness
e.g. Salmonella
Chemical (C)
• Food poisoning, chronic illness
e.g. Cleaning chemicals, pesticides
weed killers, additives, poisonous foods
Physical (C)
• Cuts to mouth, choking,
broken teeth, internal injury, burning
e.g. Glass, nails/bolts, string,
jewellery
Allergenic
• Immune reaction, anaphylactic shock
e.g. Peanuts, milk, eggs, shellfish, seeds.
A hazard is anything with the potential to cause harm

166. 9/8/2023 166
Identify control measures
• Any action or activity that can be used to prevent or eliminate
a food safety hazard or reduce it to an acceptable level.
Remember:
• More than one hazard may be controlled by a particular control
measure
• An individual hazard may require more than one control
measure

167. 9/8/2023 167
Control measures (Principle 1)
‘Actions required to prevent
or eliminate a food safety
hazard or reduce it to an
acceptable level’
Controls can be applied to:
pH
Temperature Time
a w
Additives Appearance/texture/colour.

168. 9/8/2023 168
Principle 2 – Determine critical control points
Critical control point
• A step in a process where control is essential to
prevent or eliminate a food safety hazard, or
reduce it to an acceptable level
• Effective control procedures must be provided at
all CCPs

169. 9/8/2023 169
• Control Point (good
hygienic practice)
Yes
No
Simplified decision tree
• If I lose control is it likely
that food poisoning/injury
/harm will result?
No
Yes
• Will a subsequent
step eliminate the
hazard, or reduce it to
an acceptable level?
• CCP
Critical control point.

170. 9/8/2023 170

171. 9/8/2023 171
Principle 3 - Establish critical limits
Critical
limit
Target
8°c 5°c
Refrigerator
Cooking temperature 75°c 78°c
Critical limits must be unambiguous
and measurable
Critical limits
“values of monitored actions
which separate the acceptable
from the unacceptable”.
Target levels
“control criteria that are
more stringent than the critical
limits”.

172. 9/8/2023 172
Principle 4 – Establish monitoring procedures
Monitoring
• The planned observations and measurements of
control parameters to confirm the process is
under control and critical limits are not
exceeded.
• Rapid detection and correction
• Automatic or manual

173. 9/8/2023 173
Monitoring plans
• Should include:
• Who - who's responsible for the monitoring
• When - Time
• How often: frequency
• How – e.g. equipment used, supported by documented procedure
(SOP)
• What – critical limit, targets & tolerances
• Where – at what CCP

174. 9/8/2023 174
Types of monitoring
• Observation/ supervision
• Visual inspections
(of premises,
vehicles or practices)
• Organoleptic
(senses)
• Daily checking of controls/
records. e.g. date codes).
• Measuring
(temp/weight/volume)
e.g. refrigerator
• Competency
Testing

175. 9/8/2023 175
Principle 5-Establish corrective action
• The action to be taken when a critical limit is
breached
• Remedial action should be taken before a critical
limit is breached
• Corrective action should bring the CCP under
control and deal with any affected product

176. 9/8/2023 176
Product outside critical limit
• Corrective action should specify the treatment of affected product
(quarantine, testing, reprocessing, disposal and recall)
• Continue process, e.g. extend cooking time
• Change shelf life, e.g. use immediately
• Release after examination/ sampling/ testing
• Use for different purpose

177. 9/8/2023 177
Principle 6 – Verification and Review
Validation
• Obtaining evidence that elements of the
HACCP plan are effective, especially the
critical control points and critical limits
Verification
• The methods, procedures, tests, and other
evaluations, in addition to monitoring, to
establish if the HACCP system is
functioning as planned
Audits
• Analysis of complaints
• Microbiological/chemical
tests.

178. 9/8/2023 178
What is review?
The HACCP system should be reviewed:
• If things go wrong,
e.g. food poisoning
• If there are significant changes,
e.g. new ingredients, law, process or product.
• It is a reassessment of the HACCP system to
ensure its continued validity

179. 9/8/2023 179
Why is it required?
Principle 7- Establish Documentation
 Essential to the application of the HACCP system
 Appropriate to the size and nature of the business
 Demonstrates importance of CCP monitoring to staff
• Legal compliance
• External auditors
• Prove business is well
managed
• Company policy
• Verification/internal audits
• Complaint/illness investigation
• Due-diligence defence

180. 9/8/2023 180
Benefits of HACCP
• Reduces the risk of food poisoning and food complaints
• Compliance with the law (due-diligence defence)
• Resources concentrated at critical points
• Reduced costs, e.g. waste/recall
• Generates a food safety culture/all staff involved

181. • Proactive not reactive
• Safety introduced in product development
• Demonstrates management commitment
• More effective than end-product testing
9/8/2023 181

182. 9/8/2023 182
Problems in implementing HACCP
• Over complicated
• Lack of management commitment
• Lack of training = lack of understanding
• Lack of resources
• Poor communication

183. • What ISO 22000 means?
-ISO 22000 means consensus agreements between all the economic
stakeholders concerned:
 Suppliers
 Users
 Government regulators
 Other interest groups, such as consumers
9/8/2023 183
ISO 22000

184. 9/8/2023 184
At June
2007
156 national
members
• 685 active
Committees
• 3 000 technical
bodies
• 50 000 experts
• Central Secretariat
in Geneva
• 150 staff
• Catalogue of more than
16000 published
standards
Consensus at two levels:
- Amongst global experts
- Amongst countries
through ISO members
• IT tools
• Standards
development
procedures
• Consensus building
• Dissemination
The ISO system

185. 9/8/2023 185

186. 9/8/2023 186

187. 9/8/2023 187
Implementation of the ISO Action Plan
Improving awareness
Developing capacity
Increasing regional
cooperation
Developing electronic
communications
Increasing participation
Key objectives:
Key objectives:

188. 9/8/2023 188
ISO 22000 Family of Standards
• New Family – initiated in 2001
– ISO 22000:2005 – Food safety management system –
Requirements
– ISO 22003:2007 - Requirements for bodies providing audit and
certification of food safety management systems
– ISO TS 22004:2005 - Guidance on the application of ISO 22000
– ISO 22005 – Traceability in the feed and food chain (to be
published in July 2007)

189. Reading assignment
• Read the outline of ISO 22000 and ISO family
– Section 1 – Scope
– Section 2 – Normative Reference
– Section 3 – Terms & Definitions
– Section 4 – Food Safety Management System
– Section 5 – Management Responsibility
– Section 6 – Resource Management
– Section 7 – Planning & Realization of Safe Products
– Section 8 – Verification, Validation & Improvement
9/8/2023 189

190. 9/8/2023 190
Example of ISO 22000 along the supply chain
Grain Farm Feed Mill Hatchery
Hatching
Egg Farm
Broiler
Farm
Processor
Further
Processor
Distribution
Centre
Retailer
Consumer
Trucker
Caterer
- Potentially using organization-specific ISO 22000 control measures (red)
- Potentially using externally-developed ISO 22000 control measures (green)

191. 191
Benefit of ISO 22000 society
• For businesses, the widespread adoption of ISO 22000 means
that suppliers can base the development of their products and
services on specifications that have wide acceptance in their
sectors;
• This, in turn, means that businesses using ISO 22000 are
increasingly free to compete on many more markets around the
world
9/8/2023

192. 192
Benefit of ISO 22000 for consumers
• For consumers:
- Conformity of products and services to International
Standards
-Provides assurance about:
-Quality
-Safety
-Reliability
9/8/2023

193. 193
Benefit of ISO 22000 for trade officials
• IS0 22000 create "a level playing field" for all competitors on the
markets;
• The existence of divergent national or regional standards can create
technical barriers to trade
• International Standards are the technical means by which political
trade agreements can be put into practice
9/8/2023

194. 194
Benefit of ISO 22000 for developing Countries
• ISO 22000 represents an international consensus and constitute an
important source of technological know-how;
• By defining the characteristics that products and services will be
expected to meet on export markets;
• Basis for making the right decisions when investing their scarce
resources
9/8/2023

195. 195
How ISO 22000 benefits everyone?
• Ensuring safe food
• Reducing foodborne diseases
• Better quality and safer jobs in
the food industry
• Better utilization of resources
• More efficient validation and
documentation of techniques,
methods and procedures
• Increased profits
• Increased potential for economic
growth and development
ISO 22000 can contribute to the quality of life in general by:
9/8/2023

196. 196
Benefit of ISO 22000 for the governments
For governments, ISO 22000 provides:
• Technological and scientific know-how
• Bases for developing health, safety and environmental
legislation
• Education of food regulatory personnel
• Certification or registration
• International acceptance of standards used globally
9/8/2023

197. 197
 Economic benefits
 Social benefits
 Food quality and safety
 Food security
9/8/2023

198. 198
Benefits of ISO 22000 for other stakeholders
• Confidence that organizations implementing ISO 22000 have the ability to
identify and control food safety hazards;
• International in scope;
 Provides potential for harmonization of national standards
 Provides a reference for the whole food chain
 Provides a framework for third party certification
 Auditable standards with clear requirements
 System approach rather than product approach
 Suitable for regulators
9/8/2023

199. Outbreak investigation
9/8/2023 199

200. Definition
Out-break:
• Occurrence of more cases of disease than expected.
9/8/2023 200

201. Reasons to investigate
• Control/prevention
• Research opportunities
• Training
• Public, political, or legal concerns
• Program considerations
9/8/2023 201

202. Control/prevention
• Where are we in the outbreak?
– Goals will be different depending on answer(s)
• Cases continuing to occur
– Goal: prevent further cases
– Assess population at risk, implement control measures
• Outbreak appears to be coming to an end
– Goal: prevent future outbreaks
– Identify factors contributing to outbreak, implement measures to
prevent similar events in the future
9/8/2023 202

203. Research opportunities
• Gain additional knowledge
• Opportunity to study natural history of the disease
• Newly recognized disease
– Define natural history
– Characterize the population at risk
• Well recognized diseases
– Assess impact of control measures
– Usefulness of new epidemiology and laboratory techniques
9/8/2023 203

204. Training
• Requirements of an epidemiologist!
– Diplomacy
– Logical thinking
– Problem solving ability and quantitative skills
– Epidemiologic know-how
• Pair a new epidemiologist with an experienced epidemiologist
9/8/2023 204

205. Public, political, or legal concerns
• Sometimes override scientific concerns
• Health department needs to be responsible and responsive to
public concerns
– Even if the concern has little scientific basis
9/8/2023 205

206. Program considerations
• Outbreak of disease targeted by a public health program
– Reveal a weakness and opportunity to change or strengthen
the program
• Identify population that may have been overlooked
• Failure of intervention strategy
• Changes in the agent
• Events beyond scope of the program
9/8/2023 206

207. Steps of an Outbreak Investigation
9/8/2023 207

208. 1. Preparation
• Investigation
– Scientific knowledge
• Review literature
• Consult experts
• Sample questionnaires
• Supplies
 Consult with laboratory
• Equipment
 Laptop, camera etc.
9/8/2023 208

209. • Administration-assure personnel resources, funding
– Travel arrangements (orders)
– Approval
– Personal matters
• Consultation-make sure you know your role and its parameters
– Lead investigator or just lending a hand?
– Know who to contact when you arrive
9/8/2023 209

210. 2. Establish existence of an outbreak
• Is an outbreak truly occurring?
– True outbreak
– Sporadic and unrelated cases of same disease
– Unrelated cases of similar unrelated disease
• Determine the expected number of cases before deciding
whether the observed number exceeds the expected number
9/8/2023 210

211. • Comparing observed with expected
– Through surveillance records for notifiable diseases
– Hospital discharge data, registries, mortality statistics
– Data from other facilities, states, surveys of health care
providers
– Community survey
9/8/2023 211

212. 3. Verify the Diagnosis
• Ensure proper diagnosis and rule out lab error as the bias
for increased diagnosis
– Review clinical findings, and lab results
• Summarize clinical findings with frequency distributions
– Characterize spectrum of disease
– Verify diagnosis
– Develop case definition
9/8/2023 212

213. • See and talk with patients if at all possible
– Better understand clinical features
– Mental image of disease and the patients affected
– Gather critical information
• Source of exposure
• Knowledge of others with similar illness
• Common denominators
9/8/2023 213

214. 4a. Establish a case definition
• Case definition
– Standard set of criteria for deciding whether an individual should
be classified as having the health condition of interest
– Includes clinical criteria and restrictions by time, place and
person
– Must be applied consistently and without bias to all persons
under investigation
– Must not contain an exposure of risk factor you want to test
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215. • Classification
– Definite (confirmed)
• Laboratory confirmed
– Probable
• Typical clinical features without lab confirmation
– Possible (suspected)
• Fewer of the typical clinical features
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216. 4b. Identify and count cases
• Target health care facilities where diagnosis likely to be made
– Enhanced passive surveillance e.g. letter describing
situation and asking for reports
– Active surveillance e.g. phone or visit facility to collect
information
• Alerting the public
– Media alert to avoid contaminated food product and seek
medical attention if symptoms arise
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217. • Always ask case-patients if they know of any others ill with the
same symptoms
• Information to be collected about every case
1. Identifying information
– Demographics
– Re-contact if additional questions come up
– Notification of lab results and outcomes of investigation
– Check for duplicate records
– Map geographic extent
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218. 2. Clinical findings
• Verify case definition met
• Chart time course
• Supplemental date e.g. deaths
3. Risk factor information
• Tailored to specific disease in question
4. Reporter information
• ID of person making report
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219. 5. Collection forms
– Standard case report form
– Questionnaire
– Data abstraction form
6. Line listing
– Abstraction of selected critical items from above forms
– Contains key information
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220. 5. Perform Descriptive Epidemiology
• After collection of data, characterize the outbreak by:
– Time
– Place
– Person
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221. Time
• Epidemic curve
– Histogram of the number of cases by their date of onset
– Visual display of the outbreak’s magnitude and time trend
– Where you are in the time course of the outbreak
– Future course?
– Probable time period of exposure
– Common source vs. Propagated
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222. Place
• Geographic extent of problem
• Clusters or patterns providing important etiologic clues
• Spot maps
– Where cases live, work or may have been exposed
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223. Person
• Determine what population at risk
• Usually define population by host characteristics or exposure
• Use rates to identify high-risk groups
– Numerator = number of case
– Denominator = number of people at risk
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224. 6. Develop Hypotheses
• Hypotheses should address
– Source of the agent
– Mode of transmission
• Vector or vehicle
– Exposure that caused disease
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225. • Generating the hypothesis
– What do you know about the disease?
• Reservoir, transmission, common vehicles and known risk
factors
– Talk to several case-patients
• Use open ended questions
• Ask lots of questions
– Talk to local health department staff
– Use descriptive epidemiology e.g. epi curve
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226. 7. Test Hypotheses
• Evaluate the credibility of your hypotheses
– Compare with established facts
• When clinical, lab, environmental and/or epi data
undoubtedly support hypothesis
– Use analytic epidemiology to quantify relationships and
explore the role of chance
• Cohort studies
• Case control studies
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227. 8. Refine hypotheses and do additional studies
• Epidemiologic
– When analytical epi unrevealing need to reconsider your
hypotheses
– Go back and gather more information
– Conduct different studies
• Laboratory
– Additional tests
• Environmental studies
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228. 9. Implement Control /Prevention Measures
• Implement control measures as soon as possible
• May be aimed at agent, source, or reservoir
• Short or long term
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229. 10. Communicate the Findings
• Orally within facility/community
– Local health authorities and persons responsible for
implementation of control and prevention measures
• Written reports (consider publication) for planning, record of
performance, legal issues, reference, adding to knowledge base
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230. Thank you
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231. Method for the Microbiological
Examination of Foods
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232. • Analytical Balance
• Autoclave
• Bunsen burner
• Centrifuge
• Colony Counter
• Deep Freezer
• Homogenizer
• Hot plate
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• Hot air oven
• Incubator
• Laminar Air Flow/ Laminar Hood
• Magnetic Stirrer
• Microscope
• pH Meter
List of Instruments used in Microbiology Lab

233. 9/8/2023 233

234. Methods
Rapid Method
• Direct epifluorescent filter
technique (DEFT)
• Electrical impedance
• Enzyme-linked
immunosorbent assay
(ELISA)
Traditional method
• Plate counts
• Membrane filtration
• Most probable number
• Direct microscopic count
• Dye reduction tests
234
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235. 235
Plate count method
Standard plate count (SPC)
Aerobic plate count (APC)
Total bacteria count (TBC)
Total viable count (TVC)
“Live”
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236. 236
Plate count method
•Pour plate
•Spread plate
•Drop plate
•Diluent
•0.85%NaCl
•0.1% peptone
•Phosphate buffer
•Medium
•Elective medium
•Selective medium
•General
•Petri dish plate
•Replication
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237. Plate count depends on
 Diluent
 Food homogenate
 Dilution series
 Medium
 Plating method
 Incubate conditions
237
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238. Baird-Parker Agar
• Selective agent
– Sodium tellulite
– Lithium chloride
• Elective agent
– Sodium pyruvate
– Glycine
• Diagnostic agent
– Egg yolk
238
Staphylococcus aureus
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239. 239
Plate count method
9/8/2023

240. 240
Pour plate
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241. 241
Spread plate
Number of
colony forming units (cfus)
?????
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242. Home read Assignment:
What are the disadvantage of plate count ?
242
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243. Application of plate count
• Check quality of RM & final products
• Check hygiene condition
• Estimate storage life of products
• Determine
– Production
– Transport
– Storage
• Determine pathogens
243
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244. Selection of media in food microbiology
Medium Use
• Plate count agar • Aerobic mesophilic count
• MacConkey broth • MPN of coliforms in water
• Brilliant green/Lactose/Bile
broth
• MPN of coliforms in food
• Braid Parker agar • Staphylococcus aureus
• Thiosulfate/Bile/Citrate/agar • Vibrio sp.

245. Streak technique
http://www.towson.edu/~cberkowe/medmicro/images/streak.gif

246. 246
http://www.biology.lsu.edu/webfac/rgayda/biol1011/Lecture_notes
Filtration
0.45 μm
• Low number of MO.
• Large volume of food
Liquid food
•Count
•Sterilize
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247. Most probable number(MPN)
• Most probable number Multiple tube techniques
• Pathogen
 Number too low
• Coliform
• Escherichia coli
• Staphylococcus aureus
• Feacal streptococci
247
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248. Most probable number
Medium Organisms assessed
Lauryl sulfate tryptose broth Coliforms
MacConkey purple broth Coliforms
EC broth Faecal coliform
Glucose azide Faecal streptococci
Minerals modified glutamate
medium
Coliforms
Baird-Parker broth Staphylococcus aureus

249. Microscopic count
Direct microscopic count (DMCs)
Small sample (0.01 ml) & rapid
Optical light microscope
Total cell
living & dead cells
Foods
Liquid
Semi-solid
249
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250. Microscopic count
250
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251. Methylene blue
Leuco-methylene blue
251
Resazurin (blue)
Resorufin (pink)
Dihydroresofin
(leuco)
Triphenyltetrazolium chloride (leuco)
Formazan (red)
Dye-reduction test
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252. • Hygiene indicator
• Cross contamination
252
•Fresh meat
•Raw milk
•Pasteurized milk
Indicators
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253. Direct epifluorescent filter technique (DEFT)
• Liquid food
• Filter through membrane
• Acridine orange : fluorescent
dye (fluorochrome) pour through
filter
• Epifluorescent microscopy
• Count: manual or automatic
253
• Direct microscopy
• Membrane
filtration
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254. 254
Non-viable
Viable
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255. ELISA
Antigen – conjugate enzyme
Antibody – conjugate enzyme
255
Pathogen
•Salmonella
•Listeria
•S. aureus
Toxin
•Staphylocaccal
•Botulinum toxin
•Mycotoxin
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256. Food Sampling/Preparation of Sample Homogenate
• The adequacy and condition of the sample received for
examination are of primary importance
• If samples are improperly collected and mishandled it is not
representative
• Use sterile sampling equipment and the use of aseptic technique
• Sterilize one-piece stainless steel spoons, forceps, spatulas,
and scissors
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257. • Use containers that are clean, dry, leak-proof, wide-mouthed, sterile,
and of a size suitable for samples of the product
• Identify each sample unit (defined later) with a properly marked
strip of masking tape.
• Whenever possible, obtain at least 100 g for each sample unit.
• Deliver samples to the laboratory promptly with the original storage
conditions
• When collecting liquid samples, take an additional sample as a temperature
control
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258. • Check the temperature of the control sample at the time of
collection and on receipt at the laboratory
• Make a record for all samples of the times and dates of
collection and of arrival at the laboratory
• Cool refrigerated samples in ice at 0-4°C
• Unless otherwise specified, refrigerated samples should not be
analyzed more than 36 h after collection
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259. Microscopic Examination of Foods
• https://www.fda.gov/food/laboratory-methods-food/bam-chapter-2-
microscopic-examination-foods
• https://www.fda.gov/food/laboratory-methods-food/bam-chapter-3-aerobic-
plate-count
• https://www.fda.gov/food/laboratory-methods-food/bam-appendix-2-most-
probable-number-serial-dilutions
• https://www.fda.gov/food/laboratory-methods-food/bacteriological-
analytical-manual-bam
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