pathogenic food organisms,cause of food poisoning, prevention begin from kitchen, fighting bacteria,

1. Prevention Of Food
Contamination By Pathogenic
Microorganisms
Dr: Dina Ramadan Lithy
Microbiology specialist central health laboratory
Cairo . Egypt

2. Pathogenic Microorganisms
 Very small ,Single cell organisms, seen by
microscope only.
 Eating or drinking food that contains harmful
microbes can cause food poisoning.
 Not all food APPEARING normal is safe to eat, it
may be contaminated by harmful bacteria which
cause food borne illness
2 May 2, 2012

3. Microbiological pathogens
Food poisoning
Infective food poisoning Toxic food poisoning
Occurs as a result of Some bacteria produce
eating food contaminated toxins ,these toxins cannot
with bacteria itself be removed or inactivated
Examples; Salmonella, .by cooking
Listeria and Escherichia Examples Staphylococcus
.coli aureus, Clostridium
perfringens

4. Common Food borne Bacteria

5. Salmonella
 one of the most common causes of food poisoning.
 Symptoms last 4-7 days without treatment.
 Salmonella is killed by cooking and pasteurization,
 But it can contaminate the food processing area
and transmitted to another food item.
Source
Raw poultry and eggs
 Undercooked poultry and meat
5 May 2, 2012

6. Staphylococcus aureus
 It is commonly found on the skin , hair ,
noses and throats of people and animals.
 It can multiply quickly at room
temperature and produce a toxin
that causes Food poisoning
Source ;
 Salads, macaroni
 Bakery products, cream pies,
and chocolate éclairs
 Milk and dairy products,
6 May 2, 2012

7. EHEC (Enterohemorrhagic E. coli)
E. coli (0157:H7)Lives in intestines of healthy cattle
 It produce enterotoxin causes hemolytic
inflammation of the intestines results in bloody
diarrhea hemorrhagic uremic syndrome (HUS)
• Source :
– Undercooked hamburger , salami
– Unpasteurized milk, Well water
– Fruits and Vegetables
7 May 2, 2012

8. Shigella
 It causes diarrhea in human which called bacillary
dysentery,, Shigellosis is a cause of traveler’s
diarrhea from food and water contaminated in
developing countries.
Source :
Salads and sandwiches
 Raw vegetables
8 May 2, 2012

9. Listeria
 It is widespread in nature, in soil and water .
 It grows at low temperature and in refrigerator.
 It is very dangerous pathogens for pregnant
women; it can transmit from mother to baby through
placenta results in abortion.
Source
 Ice-cream ,unpasteurized milk,
soft cheeses
 Ready-to-Eat foods, salads
9 May 2, 2012

10. Vibrio
 this bacteria found in warm coastal areas and in the summer
months when water gets wormer
 V. parahaemolyticus typically causes non-bloody diarrhea
 V. cholerae cause watery diarrhea (called "rice water stools"
 It cause electrolyte imbalance by Losing body fluids
 Severe cases, 12 - 20 liters of liquid lost in a day
 Untreated cases - Mortality Rate about 50%
 By treatment with electrolytes mortality 1%
Source :
 Raw or undercooked fish and shellfish
 Drinking contaminated water
 Eating food washed or made with
contaminated water
10 May 2, 2012

11. Clostridium perfringens
 One of the most common spore forming bacteria
causing food poisoning.
 Cooking kills Bacterial cells, but the spores grow
into new cells.
 When food prepared in large quantities and kept
long time before serving it cause infection
 Outbreaks usually linked to institutions (hospitals,
school cafeterias, and prisons).
 Sources
such as Beef and Poultry
11 May 2, 2012

12. Clostridium botulinum
 This is one toxin producing bacteria producing
neurotoxin
 Leads to flaccid paralysis.
 (Botulism) is rare but fatal caused by eating
food contamination as it end by death .
Sources:
 Honey, home-canned vegetables and fruits, and
salted fish .
12 May 2, 2012

13. Bacillus cereus
It is type of bacteria that produces toxins.
 These toxins can cause two types of illness:
diarrheal toxin, emetic toxin,
 It presents in food and can multiply quickly at
room temperature
Source :
 Rice , sauces, soups
 Food that have stayed too long at room
13
temperature May 2, 2012

14. Symptoms of food poisoning

15. General symptoms
Fever, chills, malaise , aches, swollen lymph nodes
• Salmonella typhi,
• Listeria monocytogenes,
• Campylobacter. Jejuni
Upper GIT signs
Nausea, vomiting, abdominal pain, diarrhea &
• S. aureus and its toxins
• B. cereus and its toxin
15 May 2, 2012

16. Lower GIT signs
Lower abdominal cramps & diarrhea :
• Clostridium perfringens,
• Bacillus cereus
• Salmonella, Shigella,
Neurological signs
Visual disturbances, vertigo
& paralysis
16
Clostridium botulinum May 2, 2012

18.  The main cause for food poisoning is eating
food contaminated by Bactria
 The bacteria need suitable condition to
multiply as temperature, moisture, oxygen and
have some protein,

19. In suitable condition
One bacteria multiply to more than four million
bacteria in eight hours, and make food unsafe
to eat within few hours.

20. controlling bacteria
Controlling bacteria, make food safe . and
Prevent food poisoning begin from kitchen
by:

21. controlling bacteria
 Cooking at proper temperature destroys harmful
bacteria that may be present in food
 Chilling By following Cooling , Freezing rules
control bacterial growth can be controled
 Cleaning surface , products , wash hands and
good hygiene.
 Separation to prevent cross-contamination
via hands, utensils, surfaces

22. Temperatures control
 Most types of pathogenic
bacteria can grow in
temperature from 41ºF to
140ºF (5ºC to 60ºC) which
called temperatures danger
zone (TDZ),
 To prevent bacteria from
growing, we must set the
refrigerator temperature not
higher than 39ºF (4ºC).
 Refrigerator must not be
too full, as Cold air must
circulate to keep food safe.

23. cooking
 Heating the food for enough time and at high
temperature, kill harmful microorganisms
 Always stir while heating and rotate food to
distribute heat.
 Avoid :
 Interrupted cooking. Never refrigerate partially
cooked products to be later cooking in the oven.
 Traditional recipes for limited cooking: as
eating Raw oysters, raw ground beef, and soft
boiled eggs.

24. Microwave cooking
 Microwaved food may have cold spots which
are ideal for bacterial growth.
 When use it for reheating food it must be
leftovers to minimum of 165ºF (74ºC) and serve
immediately.

25. Freezer temperatures
it Slow bacterial growth but do not necessarily kill
bacteria.
 If food has been temperature-abused before
freezing it will be unsafe upon thawing
 Food must be stored properly to be safe.
The Thawing law
 Never defrost food at room temperature.
 Thawing food in the refrigerator.
 For a quick thawing, thawing in the microwave if
cooking immediately.

26. leftovers
Remember
 Refrigerate food within 2 hours.
 Keep leftovers in small containers for quick
cooling.
 Use a cooler or ice pack to keep perishable
food cold, especially on hot summer days.
 When in doubt, throw it out!

27. Keep Clean
Wash hands, utensils, and surfaces, in hot, soapy
water before and after food preparation
For protection against bacteria use disinfectants
cleaners or a mixture of bleach and water on
surfaces.
27

28. Keep Clean
All cutting boards
 Cutting boards (including plastic, acrylic, and
wooden boards)
 Should be run through the dishwasher or
washed in hot, soapy water after each use
Produce:
 Wash raw produce under running water.
 Use vegetable brush to remove surface
dirt.
 Cut away any damaged or
bruised areas .

29. Keep Clean
Wipe up spills in the refrigerator,
microwave immediately.
Towel
 If using cloth towels, wash them in the
boiling water
 Using paper towels to clean up kitchen
surfaces. Then , throw it away

30. separation
Separation to prevent cross contamination:
 Safely Separate
Separate raw meat and seafood
from other food in refrigerator
to avoid cross-contamination
 Clean up
 Wash hands, cutting boards, dishes
after contact with raw meat,
or unwashed products.

31. Take two separate
 USE one cutting board , Knife etc ,for raw meat,
and another one for salads and ready-to-eat
foods.
 Never place cooked food on the same plate or
cutting board which previously held raw food.
 Handling dairy products , raw meat,
then prepare salads, sandwiches
can create “Cross-contamination”.

32. Restaurants staff personal hygiene
They must have Basic food safety educationand
:correct personal hygiene
 Clean hands and clothing.
 Minimize jewellery on hands.
 Tie-back or cover hair.
 Wearing gloves.
 Clean and short fingernails.
 Sick personal not prepare
food
 Avoid :
 touching face and hair.
 cough or sneeze over food.
 taste food with your fingers.

33. Pest Control
Food must Stored in tightly closed containers to
keep out pests.
Flies:
 Windows and doors must properly closed.
 Use fly proof mesh if possible.
 After applying pesticide spray, always maintain a
time gap before reusing kitchen to prepare food , also wash
utensils before reuse
Ants:
 Always keep kitchen countertops clean
Rodents:
 Use food traps.
 If using rat poisons, don’t keep it for extended period.

34. Hazard Analysis
and Critical Control Point
(HACCP)

35. The HACCP
 It is the system that is required for any food
business or organisation in most countries.
 The joint FAO / WHO Codex Alimentarius
Commission recommends the HACCP approach to
enhance Food Safety in all process of food
production.

36. The HACCP Advantages
Gives insight in the critical control points of the
product process
 Gives trust for the consumer that products are
produced safely and hygienically
 Reduces the costs of food borne illness.

37. The HACCP disadvantages:
 Need to train supervisors, managerial and
production staff
 Reduced Staff time available for other tasks
 Increased production , implementation and
supervisory costs
 Reduced flexibility in production process and
introduction of new products.

38. Remember to make food safe
 Food pathogens enter food chain at multiple points.
 Fight bacteria by cook , clean , chill and separate.
 Maintain a clean and sanitary environment for all
areas of food production.
 Apply good personal hygiene.
 Prevent cross contamination in the kitchen.
 All organization dealing with food production must
enforced by governments to applying HACCP system