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Food Safe : Preventing Food Contamination. In one year, how many Canadians get a food-borne illness? (like 24 hr stomach flu)?. Each year, 10 – 12 Million Canadians get sick from foods they have eaten. What is the main cause for contaminated food?.
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In one year, how many Canadians get afood-borne illness?(like 24 hr stomach flu)?
Each year, 10 – 12 Million Canadians get sickfrom foods they have eaten.
The main cause of food-borne illness is thatthe food has not been chilled quickly enough. • When the temperature is between 4 – 60 celsius (not too cold or too hot), bacteria can grow and spoil the food.
The main cause of food-borne illness is thatthe food has not been chilled quickly enough.
All foods contain bacteria which multiply rapidly when the temperature is between 4 celsius and 60 celsius. • A bacterium reproduces by splitting every 20 minutes when temperatures are around 20-37 celsius. As they live and grow, many bacteria give off wastes called toxins which spoil and even poison food.
Foods spoil and rot because of bacteria that grow in the food.
Controlling Temperature Controls Bacteria Growth • If the temperature is between 4 Celsius (C) and 60 C, bacteria grow. • Bacteria are greatly slowed (but not stopped) at temperatures at or below 4 Celsius. • Most bacteria are killed above 82 Celsius. • Food kept 4 hours at temps 4-60 C have enough bacteria to make a person sick.
Keeping food in the danger zone dramatically increases bacteria growth and food contamination.
The Top Ten Improper Food Handling Practices • 1. Improper cooling (30%) • 2. Advance preparation (17%) • 3. Infected person (13%) • 4. Inadequate reheating for hot holding (9%) • 5. Improper hot holding (9%) • 6. Contaminated raw food or ingredient (5%) • 7. Unsafe source (4%) • 8. Use of leftovers (3%) • 9. Cross-contamination (3%) • 10. Inadequate cooking (2%)
Microbes • Microbes are extremely small living things that can only be seen with a microscope. Disease-causing microbes are called pathogens.
Kinds of Microbes • 1. Bacteria like salmonella, staphylococcus, E. coli and listeria • 2. Viruses are smaller than bacteria, like the Hepatitis A virus, Norwalk virus and HIV virus • 3. Parasites are larger than bacteria and may be small animals like tapeworms and roundworms. • 4. Protists are one-celled microbes, larger than bacteria but smaller than parasites. Giardia found in natural waters causes Beaver Fever which produces intestinal discomfort and diarrhea. • 5. Fungi include the molds and yeasts, typically producing fuzzy growths on spoiling foods.
Growth Requirements For Microbes • 1. Microbes require a food source (protein). • 2. Microbes require the right temperature. (5-60 C) • 3. Microbes require moisture. • 4. Microbes require the right pH. A pH of 7 is neutral, lower than 7 is acidic and higher than 7 is alkaline or basic. • 5. Many microbes need oxygen but viruses and some bacteria do not need oxygen
Growth Requirements: A Closer Look at pH • The lower the pH, the more acidic the substance is. • Most bacteria grow best in substances with a pH of from 5-10. Some grow in acidic substances (pH 2-3) and some in alkaline substances (pH 10-12). • Many foods with a low pH (very acidic) inhibit (slow down) the growth of bacteria. Pickled foods (foods in acids like vinegar) stay preserved from bacteria spoilage for long periods of time.
Common Bacterial Food Contaminators: Staphylococcus • 1. Staphylococcus aureus is a round bacteria found in 40% of people’s noses and throats. Coughing and sneezing on food is about 50% likely to contaminate it with staphylococcus bacteria. In addition, 15% of all people carry staphylococcus on their skin. There is a 15% chance if a person touches their face or skin elsewhere, and then handles food, that they will contaminate the food with staphylococcus bacteria. • 2. Symptoms of Staph poisoning are abdominal cramps, vomiting and low body temperatures.
How Staphylococcus Causes Food-Poisoning • The staphylococcus bacteria make a toxin that is colorless, odorless, tasteless and heat stable (cooking does little to destroy it). • It takes a few hours (generally over three hours at a warm temperature) for the toxins to be made so food contaminated with the bacteria and left for over three hours at warm room temperatures may develop toxins. • Cooking a staphylococcus-contaminated food will kill the bacteria and this stops toxin formation from that time forward.
Common Bacterial Food Contaminators: Salmonella • Salmonella is a type of bacteria. It is usually found in poultry, eggs, unprocessed milk and in meat and water. It may also be carried by pets like turtles and birds.The salmonella bacteria attacks the stomach and intestines (diarrhea, vomiting and fever). In more serious cases, the bacteria may enter the lymph tracts and blood vessels. Persons usually recover in 3-7 days. Children and sick or elderly persons are much more likely to get serious and life-threatening complications.
Preventing Salmonella Growth in Food • Cooking food kills Salmonella bacteria. Since they cause illness directly, NOT by toxins, Salmonella are no longer a threat when food is sufficiently cooked. Eggs, poultry and fish can pick up salmonella from their environments. Raw eggs and fish (sushi) may contain salmonella. When food under-cooked (below a temperature of 60 Celsius/140 F), Salmonella can grow as long as the temperature is between 4-60 Celsius.
Common Bacterial Food Contaminators: E. Coli (Escherichia coli) • E. coli is a bacteria normally found in the intestines of mammals. As long as it stays inside the intestines, it helps the mammal break down foods and makes vitamins. • When animals are butchered, if intestines are cut, wastes in the intestines with E.coli can be mixed with cuts of meat, contaminating the meat. Ground meats like hamburger are especially susceptible to E. coli contamination.
Food Safe Measures to Avoid E. Coli Poisoning • Ground beef should be cooked to an internal temperature of 71 C (160F). This is medium-well to well-done. Patties should not be eaten if they are pink inside. • After working with ground beef, wash hands before working with other foods. This avoids cross-contamination of foods, which means not bringing bacteria from one food to another food.
Symptoms of E. Coli Poisoning • When infected with E. coli, a person will show symptoms from 1 hr – 10 days later. • Symptoms include severe abdominal cramps and possibly bloody diarrhea. • Recovery for healthy adults is usually within 10 days. • 15% of infected persons may develop HUS, a kind of serious kidney failure.
Botulism • Clostridium botulinum This bacterium produces poisonous toxins as it lives in a food. This bacterium can live without oxygen. It is killed by heat but it makes tough spores inside themselves which resist heat and which grow back into living bacteria after the temperature drops. Garden beans often have these bacteria on them. If garden beans are canned, just in boiling water, the spores survive, become toxin-producing bacteria which means the canned beans are then poisoned. Canning with a pressure cooker for 15 minutes at 15 pounds of pressure kills the spores.
Less Common Bacterial Food Contaminators: Listeria • Listeria bacteria are commonly found in soils, vegetation, sewage, silage and faeces. Farm animals may carry listeria bacteria, transferring it to meat and dairy products. In Canada, processed sandwich meats, hot dogs and soft cheeses have on occasion contained listeria. • Listeria is fatal for 20-30% of the persons who get it. • Pregnant women with listeria are likely to miscarry. Persons with weak immune systems, children and the elderly are especially susceptible to listeria. • Symptoms are vomiting, fever, diarrhea and headaches.
Food Safe Measures to Avoid Listeria Poisoning • Cooking past 140 C kills listeria • After working with meats, disinfect the counters with a weak bleach solution. • Be sure to carefully clean fruits and vegetables. • Refrigerate cooked foods within 2 hours. • Never defrost at room temperature. • Don’t keep leftovers past 4 days. • Fridges should be at or below 4 C. • Regularly disinfect fridges with weak bleach solution. • Never eat raw hot dogs. • Avoid cross-contamination of raw hot dogs/package liquid with other foods.
What to do when you have food-poisoning symptoms? • Since many food-borne illnesses have similar symptoms, get to a physician who can do a proper diagnosis. • If you are healthy (not elderly or a child), you will likely get better within a day(s).
Food Intoxication • When foods are contaminated with chemical poisons like cleaning agents, pesticides or dissolved metals, rather than bacteria, this is called intoxication. • Storage of chemicals near foods can lead to intoxication. • Acid foods like tomatos, sauerkraut, pineapple and juices will dissolve tin,copper, and lead in cans. Storage of these should be in plastic.
Physical Causes of Food Contamination • When things like glass, wood splinters, toothpicks, hair, bandages, metal particles or insect parts fall into foods, this causes physical contamination which likely can lead to bacterial contamination because the objects probably have bacteria on them. • Flies carry bacteria all over their bodies. Flies that walk on food may just have come from faeces, carrying bacteria with them!
Stop Food Contamination By….. • Keeping fingernails clean and trimmed. Brush nails clean
Stop Food Contamination By….. • Washing hands in soapy water beyond the wrist for 20 s using rotary motions, getting between fingers. • Rinse under a downward flow of water. • Dry hands on a fresh paper towel.
Stop Food Contamination By….. • Re-washing hands after touching your nose, face, hair, clothes or unwashed objects.
Stop Food Contamination By….. • Preventing cross-contamination of foods. Cross-contamination happens when hands or a tool working with one food that may carry bacteria (like raw meat) is used in preparing another food (like vegetables or salad greens) WITHOUT being sanitized with a disinfecting soap or weak bleach solution. • Bringing bacteria from one source to a new food source is cross-contamination.
Poultry Food Safe Precautions I • To reduce the chances for Salmonella growth, wash hands after handling with an antibacterial soap and cutting boards (should be plastic rather than wood) and work areas with a hot soapy water solution.
Poultry Food Safe Precautions II • When stuffing a bird, cook immediately after stuffing. Do not refrigerate a stuffed bird since the bird cavity provides an ideal dark, moist environment for bacterial growth. After cooking, remove the stuffing for serving and storage.
Poultry Food Safe Precautions III • When storing or defrosting uncooked poultry, place on a tray on the lower shelf of a refrigerator to prevent juices from dripping onto other foods. • Once thawed, cook poultry within 48 hours. • Wash chicken and pat dry with paper towels before marinating (soaking in a mixture of wine and seasonings).
Poultry Food Safe Precautions IV • When storing cooked poultry, refrigerate quickly without waiting for it to cool. • Stuffing should be eaten within three days, discarding it after this time. Chilled, cooked chicken should be eaten within 2-3 days.
Stop Food Contamination By….. • Proper personal sanitation when using a washroom. • After washing hands, use a clean paper towel to turn off tap fixtures.
Stop Food Contamination By….. • Using gloves when hands have bandages or small sores. • Replace gloves frequently to prevent contamination.
