2. INTRODUCTION
• Food, apart from being necessary for growth, energy
& development can also spread disease.
• Food is a potential source of infection which is
liable to contamination by micro-organisms while
passing through the producer to the consumer. This
may arise from:
• Contamination by human or animal excreta
• Microorganism who also use the same food as food
• Natural process of food spoilage due to the activity
of enzymes
4. FOOD SAFETY/HYGIENE
Definition: Food Safety/ Food Hygiene is defined as
all conditions and measures that are necessary during
production, processing, storage, distribution and
preparation of food to ensure that it is safe, sound
,wholesome and fit for human consumption. (WHO)
5. FOOD HYGIENE AND SAFETY
• Food Hygiene: can be described as
practices in food handling that help to keep food
clean and safe to eat in order to avoid food
poisoning due to bacterial, fungal, viral or chemical
contamination of food.
• Food safety: can be defined as the absence of
adverse health effects following food consumption
6. COMMON NIGERIAN FOODS
• Nigerian foods have a rich variety. Reports suggest
that over 21 different types of starchy roots and
tubers, 21 types of nuts/ seeds. 20 types of legumes,
116 types of vegetables, 12 varieties of mushrooms
and 36 varieties of fruits exist all year round.
• Meat and fish are part of the daily food. Bush meat is a
delicacy in many parts.
• In addition to staple foods, Nigerians prepare and use a
variety of fermented foods where microorganisms play
an important role.
7. FOOD HYGIENE
• Important international program carrying out
activities in the field of food hygiene is the joint
FAO/WHO food standard program, while in
Nigeria, NAFDAC and SON are solely
responsible.
• Food safety is considered an essential component
of primary health care.
• The primary aim of food hygiene is to prevent
food poisoning and other food-borne illnesses.
8. REASONS FOR FOOD HYGIENE CONTROL
1. Development of community feeding in schools,
factories, hospitals etc.
2. Increase in food consumption outside home
evidenced by increased number of catering
establishments & development of provision of
meals/snacks in public places etc.
3. High levels of contamination of some foods entering
retail food premises.
4. Poor level of understanding of food hygiene
practices by workers in food industry at both
managerial & operative levels.
5. Inadequate temperature control of risk foods i.e.
meat & meat products, milk, fish & fish products
9. PRINCIPLES OF FOOD HYGIENE
1. Personal Hygiene:
• Wash hands: before commencing work, after using the
toilet, between different work tasks especially after
handling raw foods.
• Wear clean protective clothing including a suitable,
effective hair covering.
• Keep all cuts, boils etc, covered with waterproof
dressings.
• Keep fingernails short.
• Do not cough or sneeze over food.
• Do not touch the mouth, nose or face – at least without
washing your hands afterwards.
• Report any illness which may be food poisoning to the
supervisor and consult your doctor.
10. PRINCIPLES OF FOOD HYGIENE
2. Food Storage:
• A good system of stock rotation should be operated
through which the oldest stock is used.
• Stock should be kept at least a few inches off the
ground to give a circulation of air and to enable
insect and rodent infestations to be detected.
• Food stores must be adequately ventilated and be
kept at a temperature below 10oC.
• Refrigerators, Chillers, Freezers etc. must be
regularly checked for operating efficiency against
their designed temperature range.
• Keep food either hot, i.e. above 630C, or cold i.e.
below 10oC
11. PRINCIPLES OF FOOD HYGIENE
3. Cross Contamination:
Avoid contamination of a ready–to-eat risk food by
another food directly by way of a transmitting agent.
Keep raw and cooked foods separate at all times including
in storage.
Use separate surfaces, utensils and other equipment for
the preparation of raw and cooked food.
Separate staff should be used for handling raw and cooked
food.
Cleaning and sterilization of food slicing machinery.
Avoid reheating of foods where possible. Reheated food
should be brought to temperatures above 63oC.
12. PRINCIPLES OF FOOD HYGIENE
4. Temperature Control: Factors such as moisture,
type of food, time & temperature facilitates the
growth of food poisoning organism.
• Risk foods should be kept as short a time as
possible at temperatures which are conducive to
bacterial growth, i.e. between 10oC and 63oC.
• Below 10oC : No bacterial growth; Above 63oC:
Pathogenic organisms are destroyed.
• Food processing temperatures are critical to the
production of safe product and should always be
checked where risk foods are involved.
14. PRINCIPLES OF FOOD HYGIENE
6. Equipments: Equipments in food premises must be:
• Constructed so as to facilitate ease of cleaning
• Non-absorbent;
• Placed in such a way that cleaning is possible on all
sides;
• Well maintained.
7. Cleansing: The fundamental objective in food
premises is the killing of pathogenic organisms and
elimination of situations in which they might thrive.
• Cleaning of the structure, equipment and working
surfaces should be planned based on principle of
good house keeping.
15. PRINCIPLES OF FOOD HYGIENE
7b. Cleansing materials:
• Detergents: Reduce surface
tension & remove grease, thus
enabling sterilants to act
effectively.
• Sterilants or Disinfectants:
Kill bacteria. Examples:
Hypochlorites, Iodophors,
Quaternary Ammonium
Compound (QAC), Phenolic
disinfectants.
8. Use of PPE in Food
Premises:
Hair Net Hand Gloves Aprons/Hygienic Wear
16. HIGH RISK FOODS
These are foods with greatest risk of microbial
contamination because they are processed or
stored within the temperature of 10°C to 63°C in
an unsterilized environment.
This include meat, poultry, dairy products,
eggs, seafood, cooked rice, cooked pasta,
prepared salads, coleslaws, pasta salads,
prepared fruit salads...etc.
17. GOOD PRACTICES FOR PREPARATION
AND COOKING OF HIGH-RISK FOODS.
• A Calibrated Digital Probe Thermometer should be used
to check temperatures randomly.
• Rapid cooling of food: if not for immediate service,
cooked food must be cooled quickly and refrigerated. No
cooled food should be left for longer than 1.5 hrs without
refrigeration.
• All high-risk food and ingredients should be refrigerated
below 10oC or kept above 63oC if not for immediate
service.
• Cross-contamination must be avoided, and separate
designated areas should be used for raw meat and other
foods.
• No food should be prepared too far in advance and re-
heating should be avoided.
18. FOOD HANDLERS
• Proper handling of foods, utensils and dishes and
good personal hygiene are of great importance.
• The infections which are likely to be transmitted by
the food handlers are diarrhoeas, dysenteries,
typhoid and para-typhoid fevers, entero-virruses,
viral hepatitis, protozoal cyst, eggs of helminths,
strepto and staphylococcal infections, and
salmonellosis.
Complete medical examination carried out of all
food handlers at the time of employment is
necessary.
19. FOOD HANDLERS CONTD
Any person with a history of typhoid fever, diphtheria,
chronic dysentery, tuberculosis or any other communicable
disease should not be employed.
Persons with wounds, otitis media or skin infections should
not be permitted to handle food or utensils.
Day to day health appraisal of the food handlers is
important; those who are ill should be excluded from food
handling.
Any illness which occur in food handlers family should at
once be notified.
Education of food handlers in matters of personal hygiene,
food handling, utensils, dish washing, and control of insect
and rodent is the best means of promoting food hygiene.
20. FOOD CONTAMINATION
• It is the presence of a substance or agent that makes
food unsuitable for consumption.
• Foods may be contaminated by physical, chemical
or biological agents .
• Physical agents include sand, wood, metals, nails,
hair, debris, radiation, etc.
• Chemical agents may be pesticides, cleaning
materials used in the house, and toxic chemicals
arising from outside sources
• Biological agents are bacteria, viruses, yeast,
moulds and parasites or their eggs
21. FOOD CONTAMINATION
Food can be contaminated through:
1. Production
2. Processing
3. Handling
4. Transportation
5. Eating
.
22. FOOD CONTAMINATION
There are 5 agents that can contaminate food:
1. Microorganisms
2. Toxins: Exotoxins: toxins released on the
food by microorganism. Endotoxins:
microorganisms grow inside the food and
produces toxins in its cells.
3. Chemicals: Chemicals added illegally or
ignorantly. They are normally;
Preservatives e.g Vinegar, Salt, Sugar,
tartaric acid etc. some food industries use
sodium benzoate for preservation. This is
known to be carcinogenic
23. FOOD CONTAMINATION (CONTD)
Artificial sweeteners: Sugar (10kg/head/per
year is recommended). 25-30g/day/person.
Cyclamates: Are derived from coal tar, by-
product petroleum, a product of benzene
hydrocarbon, causes cancer.
Sweetners e.g saccharine: they are also
carcinogenic, causes cancer of the kidney.
Flavors and Colorings: They are products of
Hydrocarbon materials.
24. FOOD CONTAMINATION (CONTD)
Adulteration: Adulterated products are
harmful. Oil used for frying more than 3
times will be contaminated and harmful.
Monosodium glutamate: Glutamate is not
easily metabolized by the cells. It causes
Chinese syndrome. Symptoms –Cramps,
body pains. It can cause cancer of the bone,
kidney etc. Limited use of this substance
should be encouraged.
25. FOOD CONTAMINATION (CONTD)
4. Natural Toxins: Some food naturally contains toxin
materials. Examples are
• Groundnuts Afflotaxins
• Fishes Accumulates heavy metals
• Cassava Cyanides
• Mushrooms Alkaloids; this cannot be destroyed
by heat. This results in abdominal
cramps.
• Potatoes (Irish) Solanin is a form of alkaloides. It can
be destroyed by heat
• Note: The toxins are protective materials for the plants.
5. Parasites: Such as Tape worm (Taeniasis Trachuriasis). All
produce toxins in the food.
26. DYES/COLOURANTS - Effects
• Amaranth (E123): cause cancer, birth defects, still births,
sterility and early foetal deaths.
• Ponceau (E124): used mainly in dessert mixes, weak
carcinogen
• Erythrosine (E127): used in candied cherries and
children’s sweets; found to act as a potent
neurocomptetitive dopamine inhibitor; possible carcinogen.
• Caramels (E150): over 100 different formulations are
currently in use, mostly by cola drinks, beer and alcohol
industry. It is also used as a colourig agent in crisps, bread,
sauces, gravy.
• Brown FK: mainly used as a colouring agent in fish such
as kippers; cardiotoxin,
27. DYES/COLOURANTS - Effects
• Tartrazine (E102): is primarily used by the soft drink
industry, implicated in food intolerance; symptoms include
feeling of suffocation, weakness, heat sensation, blurred
vision.
• Curcumin E100: used mainly in flour, confectionery and
margarine; found to cause mutations in bacteria; thyroid
damage.
• Sunnet yellow (E110): used in biscuits, found to damage
kidneys and adrenals; carcinogenic.
28. PRESERVATIVES/ANTIOXIDANTS
• Benzoates E210 – 219: used mainly in marinated
fish, fruit –based filling, jam, salad cream, soft drinks,
beer; found to provoke urticaria, angioedema and
asthma; childhood hyperactivity.
• Nitrates and nitrites E220 – 227: used in corned
beef and some cheese; found to cause headache in
susceptible individuals; linked with cancer &
mutagenecity.
29. PRESERVATIVES/ANTIOXIDANTS
• Butylated hydroxyanisole – Bha E320: used in
soup mixes and cheese spread; found to be tumour-
producing; linked with angioedema and asthma.
• Sulphites E220 – E227: used mainly in dried fruits,
fruit juices and syrups, beer and wine; linked with
pruritus, urticaria asthma and angioedema.
• Carmoisine (E122): used in jams and preserves,
unavoidably contaminated with low levels of beta –
napthylamine, a well-known mutagen.
30. SWEETENERS
• Sacharin: used in soft drink and sweet food
industries; known to be carcinogenic, mutagenic,
and growth inhibitor in animals
• Aspartame: has key ingredient phenylalanine
widely used by soft drink and sweet food
industries; increases brain tyrosine, followed by a
considerable reduction on brain tryptophan levels
resulting in aggressive and violent behaviour.
• Sucrose/Table sugar: lead to reactive
hypoglycaemic condition on low protein diets;
increases children’s restless and destructive
behaviour. Consumption of 10Kg/person/annum is
recommended.
31. BACTERIAL CONTAMINATION (VEHICLES
AND ROUTES)
Clean food can be contaminated by bacteria from
four main sources -
- the people present in the workplace and their
clothing.
- other food that is already contaminated.
- dirty kitchen or work premises and equipment.
- insects and vermin.
Sometimes, harmful bacteria pass directly from the
source to high risk food, but, usually they rely on
other things to transfer them to food. These things
are called Vehicles.
32. • Indirect contamination using an intermediate
vehicle is the most common, e.g.- the
movement of bacteria from the intestine of a
food handler to food via unwashed hands, after
using the toilet.
• Where contamination is passed from raw food
to high risk food via for example, a cutting
board, this is known as Cross Contamination.
• The path that bacteria use to move from the
source to the food, is known as the Route.
33. Cross Contamination
Cross contamination is what happens when
bacteria from one food item are transferred to
another food item, often by way of unwashed
cutting boards or countertops, as well as knives
and other kitchen tools, or even unwashed
hands.
Cross contamination can in turn lead to food
poisoning.
34.
35. • Route: The most common route is the faecal-oral
route
water
soil
faeces
fingers
flies
food mouth
Faecal-oral transmission routes
36. CLASSIFICATION OF FOOD
• Milk & Milk products
• Meat & Meat products
• Fish & Fish products
• Poultry
• Beverages
• Baking
• Fruits & Vegetables
37. MILK HYGIENE
• Milk is an efficient vehicle for great
variety of disease agents. Sources of
infection or contamination:
1. Diary animal
2. Human handlers
3. Environment e.g, contaminated vessels,
polluted water, flies, dust, etc.
38. MILK BORNE DISEASES:
1. Infections of animals that can be transmitted to
man
• Tuberculosis, Brucellosis, Streptococcal
Staphylococcal infections salmonellosis & Q
fever. Cowpox, Foot and mouth disease, Anthrax,
Leptospirosis & Tick-borne encephalitis.
2. Infections primary to man that can be transmitted
through milk:
• Typhoid & paratyphoid fevers, shigellosis,
Cholera, Enteropathogenic Escherichia coli,
• Non-diarrhoeal diseases: Streptococcal infections,
Staphylococcal food poisoning , Diphtheria ,
Tuberculosis, Entero-viruses Viral Hepatitis.
39. Clean & Safe Milk
• Healthy and clean animal (healthy Udder).
• Premise where the animal is house and milked
should be sanitary.
• Water supply should be bacteriological safe.
• Milk handlers must be free from communicable
disease
40. PASTEURIZATION OF MILK
• Is the heating of milk to temperatures 68-90oC for periods
of time as required to destroy pathogens that may be
present while causing minimal changes in the composition,
flavor and nutritive value.
• It is a preventive measure of public health importance and
corresponds in all respects to the modern principles of
supplying safe milk.
• Pasteurization kills nearly 90% of bacteria in milk
including the more heat resistant tubercle bacillus & the Q
fever organisms. Do not kill thermoduric bacteria &
bacterial spores.
• To check the growth of microorganisms, pasteurized milk is
rapidly cooled to 4oC, should be kept cool until it reaches
consumers.
41. MEAT HYGIENE
• The term “meat” includes various tissues of animal
origin. The diseases which may be transmitted
eating unwholesome meat are:
1. Tape worm infestations: Tinea solium, T. saginata,
Trichinella spiralis and fasciola hepatica.
2. Bacterial infections: anthrax, actinomycosis,
tuberculosis, and food poisoning.
MEAT INSPECTION:
• Animals intended for slaughter are subjected to
proper ante mortem and postmortem inspection by
qualified veterinary personnel.
42. Principal Causes of Ante Mortem
Ejection of Animals
♦ Emaciation
♦ Exhaustion,
♦ Pregnancy
♦ Sheep-pox
♦ Foot-rot
♦ Actinomycosis
♦ Brucellosis
♦ Febrile conditions
♦ Diarrhoea
43. Principal Causes of Postmortem
Rejection of Animals
Cysticercus bovis
♦ Liver fluke
♦ Abscesses
♦ Sarcocystis
♦ Hydatidosis
♦ Tuberculosis
♦ Cystcercus
cellulosae etc.
♦ Parasitic & Nodular
infections of Liver
and Lungs
♦ Septicaemia
44. MEAT INSPECTION
• Animals to be slaughtered for human consumption
must be subjected to ante-mortem and post-mortem
inspection by qualified veterinary officers.
• Animals must be rejected if they are found with the
following conditions:
• Febrile conditions Pregnancy Brucellosis
• Exhaustion Emaciation Actinomycosis
• Sheep pox Septicaemia Tuberculosis
• Infections of liver & lungs liver fluke
• Abscesses Sarcocystis
Hydatidosis etc.
45. CHARACTERISTIS OF A GOOD MEAT
• Animals for sale or slaughter should be healthy
as demonstrated by
• Alertness
• Clear eyes
• Cool and wet nose
• Free breathing
• Normal stool
• Firm and elastic to touch
• Not slimy
• Has an agreeable odour
• Neither pale, not pink nor a deep purple tint
46. SLAUGHTER HOUSE
♦ Places where animals whose flesh are
intended for consumption are killed.
STANDARDS FOR SLAUGHTER HOUSE:
♦ Location: Away from residential areas.
♦ Structure: Floors & Walls up to 3ft should
be impervious & easy to clean.
♦ Disposal of Waste: Blood, offal should not
be discharged into public sewers but should
be collected separately. Solid waste should
be properly treated or recycle. e.g. Horns,
bones
47. SLAUGHTER HOUSE
♦ Water supply: Should be independent,
adequate and continuous.
♦ Examination of animals: Ante mortem &
Postmortem should be arranged..
♦ Storage of meat: store in rat-proof & fly-
proof rooms.
♦ Transportation of meat; Fly-proof cover
van.
♦ Temperature of rooms where meats are kept
overnight must be less than 5oC.
48. FISH
• Fish loses its freshness because of autolysis
that set in after death & also due to bacteria
effect.
• Fish is the intermediate host of the tape
worm, Dibothriocephalus latus. This
cestode is communicable to man, but rarely
encountered.
• Fish may carry Vibrio parahaemolyticus,
Salmonella spp., Clostridium botulinium
type E, and other organisms.
49. FISH CONTD
TINNED FISH:
• To inspect tinned fish (or meat or any food),
the following points should be noted:
1. The tin must be new & clean without
leakages or rusting.
2. There should be no evidence of having been
tampered with such as sealed openings
3. On opening the tin, the contents should not
be blown out which indicates decomposition.
50. FRUITS & VEGETABLES
• This group constitute another source for spreading
pathogenic organisms, protozoan and helminthes.
• When sewage is used to grow vegetables,
consumption therefore, becomes an issue of public
health importance.
• Vegetables which are consumed raw in the form of
salads pose a problem in food sanitation.
• People should be educated on the need to wash the
vegetables before eating. Cooked vegetables are free
from this danger
51. FOOD POISONING
• Food poisoning: any condition in which a food
causes a toxic reaction, whether as a result of
a toxin naturally present in the food (for example,
green or sprouting potatoes, partially cooked red
kidney beans, many mushrooms etc
a toxin acquired by the food as a result of natural
accident (such as contamination of fish or shellfish
with toxins from dinoflagellate organisms in
plankton.
fungal spoilage leading to the production of
mycotoxins in the food; or
52. Food Poisoning (contd)
Contamination of the food with toxins during
agricultural processing (for example, pesticide
residues)
Or food processing (such as accidental contamination
with industrial chemicals).
The term is generally reserved for gastrointestinal
disease resulting from bacterial (or sometimes viral)
contamination of foods
Food poisoning may occur within 1-36 hours of eating
contaminated food.
Symptoms normally last 1-7 days and may include
one or more of the following:
Abdominal pain, diarrhoea, vomiting, nausea, fever,
gastroenteritis
54. CAUSES OF FOOD POISONING
• Inadequate cooking of contaminated raw food,
and inadequate reheating of pre-cooked food,
so that the temperature is not sufficiently high
to kill the bacteria
• Keeping cooked food at temperatures that
favour the growth of bacteria
• Cross-contamination between raw and cooked
food
• Poor personal hygiene in food handlers
55. PREVENTION/CONTROL OF FOOD
POISONING
Protect food from contamination by:
- keep food covered whenever possible
- do not use unsuitable, defective or dirty
equipment
- do not use dirty wiping cloths, disposable
preferable
- only handle food when unavoidable (use
tongs, plates, & trays)
- separate raw and cooked food at all stages of
preparation, storage and distribution
- prevent insects, animals and birds from
coming in contact with food
56. PREVENTION/CONTROL OF FOOD
POISONING CONTD
- store food in rodent-proof containers and
ensure lids are tightly replaced after use
- protective clothing for all food handlers
- maintain high standard of personal hygiene
- use correct cleaning and disinfection
procedures
- refuse disposal
- purchase food from reputable sources
- environmental sanitation (clean environment
with good water supply and sanitation)
57. PREVENTION & CONTROL OF FOOD
POISONING
Prevent bacterial within food from multiplying
by:
- employing appropriate storage
temperature (store food out of danger zone-
10oC - 63oC)
- using suitable preservative (salt, sugar).
- Do not allow dry foods to absorb moisture
- other methods: canning, freezing, drying
and dehydration, smoking
58. Destroy those bacteria within food
(disinfection) by:
- thorough cooking, heat processing such
as pasteurization, sterilization (e.g. UV) or
canning
Inspection of food premises
Basic food hygiene education for food
handlers
Medical screening for food handlers
59. Good manufacturing practices (GMPs)
Adequate quality control using the Hazard
Analysis Critical Control Point (HACCP)
system.
Legislation
60. FOOD-BORNE DISEASES
• Defined as a disease, usually either infectious
or toxic in nature, caused by agents that
entered the body through the ingestion of
food.
• Food borne diseases may be classified as:
Food borne intoxications
1. Due to naturally occurring toxins in some foods
(a) Lathyrism ( beta oxalyl amino-alanine)
(b) Endemic ascitis (Pyrrolizidine alkaloids)
61. FOOD-BORNE DISEASES
2. .Due to toxins produced by certain bacteria.
(a) Botulism
(b) Staphyloccus poisons
3. Due to toxins produced by some fungi
(a) Aflatoxin
(b) Ergot
(c) Fusarium toxins
62. FOOD-BORNE DISEASES
4. Food borne chemical poisoning
(a) Heavy metals, e.g., mercury ( usually in
fish), cadmium (in certain shell fish) and lead
( in canned food).
(b) Oils, petroleum derivatives& solvents (e.g.,
Trycresyn phosphates or TCP)
(c) Migrant chemicals from package materials
(d) Asbestos
(e) Pesticides residues (DDT, BHC).
63. FOOD-BORNE DISEASES
Food borne infections
GROUP EXAMPLES OF ILLNESS IN EACH GROUP
Bacterial Diseases Typhiod fever, Paratyphoid fever,
Salmonellosis, Staphylococcal intoxication,
Cl. Perfringens illness, Botulism, B.cereus
food poisoning, E.coli diarrhoea, Non-cholera
vibrio illness, V. parahaemolyticus infection,
Streptococcal infection, Shigellosis
Brucellosis
Viral diseases Viral hepatitis, Gastroenteristis
Parasites Taeniasis Hydatidosis, Trichinosis, ascariasis,
Amoebiasis, Oxyuriasis
64. GOOD MANUFACTURING PRACTICES
Organization of personnel and training
Facilities and equipment
- Facilities: buildings, premises, services which
provide optimum environment for manufacturing)
- equipment: for manufacturing, packaging, storage
etc
Control of components
- production and process control
- packaging and labeling
- warehousing and distribution
Quality control : raw materials, materials in process,
finished product
65. AGENCIES INVOLVED IN ENSURING
FOOD HYGIENE
• NAFDAC
• SON
• Ministry of Environment
• Federal and State Public Health
Laboratories
67. REFERENCES
• Basavanthapa, B. T., Community Health
Nursing (2nd edition). Jaypee brothers medical
publishers , New Delhi
• Park, K. (18th ediition) Park’s textbook of
preventive and social medicine. Banarsidas
Bhanot Publishers, India.
