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Prevention Of FoodContamination By Pathogenic Microorganisms Dr: Dina Ramadan Lithy Microbiology specialist central health laboratory Cairo . Egypt
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 illness2 May 2, 2012
Microbiological pathogens Food poisoningInfective food poisoning Toxic food poisoningOccurs as a result of Some bacteria produceeating food contaminated toxins ,these toxins cannotwith bacteria itself be removed or inactivatedExamples; Salmonella, .by cookingListeria and Escherichia Examples Staphylococcus .coli aureus, Clostridium perfringens
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 meat5 May 2, 2012
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 toxinthat causes Food poisoningSource ; Salads, macaroni Bakery products, cream pies,and chocolate éclairs Milk and dairy products,6 May 2, 2012
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 Vegetables7 May 2, 2012
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 vegetables8 May 2, 2012
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, salads9 May 2, 2012
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 withcontaminated water 10 May 2, 2012
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). Sourcessuch as Beef and Poultry11 May 2, 2012
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
Bacillus cereusIt 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 temperatureSource : Rice , sauces, soups Food that have stayed too long at room13 temperature May 2, 2012
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,
In suitable conditionOne bacteria multiply to more than four million bacteria in eight hours, and make food unsafe to eat within few hours.
controlling bacteriaControlling bacteria, make food safe . andPrevent food poisoning begin from kitchenby:
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
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.
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.
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.
Freezer temperaturesit 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.
leftoversRemember 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!
Keep CleanWash hands, utensils, and surfaces, in hot, soapy water before and after food preparationFor protection against bacteria use disinfectants cleaners or a mixture of bleach and water on surfaces. 27
Keep CleanAll cutting boards Cutting boards (including plastic, acrylic, and wooden boards) Should be run through the dishwasher or washed in hot, soapy water after each useProduce: Wash raw produce under running water. Use vegetable brush to remove surface dirt. Cut away any damaged or bruised areas .
Keep CleanWipe 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
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.
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, sandwichescan create “Cross-contamination”.
Restaurants staff personal hygieneThey 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.
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 reuseAnts: Always keep kitchen countertops cleanRodents: Use food traps. If using rat poisons, don’t keep it for extended period.
Hazard Analysisand Critical Control Point (HACCP)
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.
The HACCP AdvantagesGives 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.
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.
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