Conditions needed for bacterial growth It is important to store, prepare and cook foods safely in order to reduce the risk of bacteria multiplying and causing foodborne illness.
Bacteria need the following conditions to grow: Warmth — Bacteria need warmth to grow. The temperature a food is stored, prepared and cooked at is crucial. If this is not followed correctly then the food will not be safe to eat. Lactic acid bacteria, such as Lactobacillus and Lactococcus together with yeast and molds, or fungi, are used to prepare foods such as as cheese, soy sauce, natto fermented soy beans , vinegar, yogurt, and pickles.
Not only is fermentation useful for preserving foods, but some of these foods may offer health benefits. For example, some fermented foods contain types of bacteria that are similar to those linked with gastrointestinal health. Some fermentation processes lead to new compounds, such as lactic acid, which that appear to have an anti-inflammatory effect. More investigation is needed to confirm the health benefits of fermented foods.
Bacteria can break down organic compounds. This is useful for activities such as waste processing and cleaning up oil spills and toxic waste. Bacteria are used in molecular biology, biochemistry and genetic research, because they can grow quickly and are relatively easy to manipulate.
Scientists use bacteria to study how genes and enzymes work. Bacillus thuringiensis Bt is a bacterium that can be used in agriculture instead of pesticides. It does not have the undesirable environmental consequences associated with pesticide use. Some types of bacteria can cause diseases in humans, such as cholera , diptheria, dysentery , bubonic plague, pneumonia , tuberculosis TB , typhoid , and many more. If the human body is exposed to bacteria that the body does not recognize as helpful, the immune system will attack them.
This reaction can lead to the symptoms of swelling and inflammation that we see, for example, in an infected wound.
In , pneumonia, TB, and diarrhea were the three biggest killers in the United States. Sterilization techniques and antibiotic medications have led to a significant drop in deaths from bacterial diseases. However, the overuse of antibiotics is making bacterial infection harder to treat. As the bacteria mutate, they become more resistant to existing antibiotics, making infections harder to treat. Bacteria transform naturally, but the overuse of antibiotics is speeding up this process.
For this reason, scientists and health authorities are calling on doctors not to prescribe antibiotics unless it is necessary, and for people to practice other ways of preventing disease, such as good food hygiene, hand washing, vaccination, and using condoms.
Recent research has led to a new and growing awaress of how the human body interacts with bacteria, and particularly the communities of bacteria living in the intestinal tract, known as the gut microbiome, or gut flora.
In , researchers published findings suggesting that women with obesity were more likely to have a particular kind of bacteria, Selenomonas noxia S. They suggest that this may have a psychological impact. Over 2, years ago, a Roman author, Marcus Terentius Varro, suggested that disease may be caused by tiny animals that floated in the air. He advised people to avoid marshy places during building work because they might contain insects too small for the eye to see that entered the body through the mouth and nostrils and cause diseases.
In the 17th century, a Dutch scientist, Antonie van Leeuwenhoek created a single-lens microscope with which he saw what he called animalcules, later known as bacteria. He is considered to be the first microbiologist. In the 19th century, the chemists Louis Pasteur and Robert Koch said that diseases were caused by germs.
This was known as the Germ Theory. Bacteria are really tiny, and are very good at absorbing mineral nutrients from the environment, so they are at the bottom of just about every food chain on the planet.
Usually, the next step up from bacteria in most food chains are protozoans such as amoebae and even microscopic crustaceans , and they are the biggest eaters of bacteria. Then there's slightly bigger animals which also feed directly on bacteria. In the sea, filter-feeding animals like fan worms and shellfish can suck bacteria out of the water.
To prevent illness, always follow the food safety steps: clean , separate , cook , and chill. Other prevention tips for specific bacteria and viruses are included below. The bacteria and viruses that cause the most illnesses, hospitalizations, or deaths in the United States are described below and include:. Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration or if your symptoms are severe, call your doctor. Antibiotics are recommended only for patients who are very ill or are more likely to develop a serious illness, such as people with weakened immune systems.
Produce, shellfish, ready-to-eat foods touched by infected food workers salads, sandwiches, ice, cookies, fruit , or any other foods contaminated with particles of vomit or feces from an infected person. Food: A variety of foods have been linked to Salmonella, including vegetables, chicken, pork, fruits, nuts, eggs, beef and sprouts.
Animals and their environments: Particularly reptiles snakes, turtles, lizards , amphibians frogs , birds baby chicks and pet food and treats. Antibiotics are recommended only for patients who have a serious illness such as severe diarrhea, high fever, or bloodstream infection , or are more likely to develop a severe illness or complications infants, adults over 65 years old, and people with weakened immune systems. If you are in a group more likely to get a Vibrio infection, such as people with liver disease:.
Menu FoodSafety. Enter the terms you wish to search for. Print Share. Bacteria and Viruses. The bacteria and viruses that cause the most illnesses, hospitalizations, or deaths in the United States are described below and include: Campylobacter Clostridium perfringens E.
Incubation period Diarrheal: hours Emetic vomiting : 30 minutes to 6 hours Symptoms Diarrheal: Watery diarrhea and abdominal cramps Emetic vomiting : Nausea and vomiting Duration of illness 24 hours What to do Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration, call your doctor. Sources Infants : Honey and products containing honey, such as infant pacifiers filled with or dipped in honey.
Infants, children and adults : Improperly home-canned or preserved foods, including low-acid vegetables and fermented fish; improperly canned commercial foods; herb-infused oils, baked potatoes in aluminum foil, cheese sauce, bottled garlic. Incubation period Infants : days Children and adults: hours Symptoms Infants: Lethargy, poor feeding, constipation, weak crying, poor muscle tone appear "floppy".
Children and adults: Double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and muscle weakness.
Duration of illness Variable What to do Botulism is a medical emergency. If you have symptoms of botulism, see your doctor or go to the emergency room immediately. Prevention Follow safe home canning instructions provided by the National Center for Home Preservation. Consult with your local Cooperative Extension Service. Most offices have a food safety specialist that can help home canning advice.
Do not feed honey or give honey pacifiers to children younger than 12 months. Sources Unpasteurized raw milk, chicken, shellfish, turkey, contaminated water. Incubation period 2 to 5 days Symptoms Diarrhea, cramps, fever, and vomiting; diarrhea may be bloody. Duration of illness About one week What to do Drink plenty of fluids and get rest. Prevention Drink pasteurized milk. Do not drink raw milk. Do not drink untreated water. Incubation period 6 to 24 hours Symptoms Diarrhea and stomach cramps no fever or vomiting , Duration of illness Less than 24 hours.
In severe cases, symptoms may last for weeks. What to do Drink plenty of fluids and get rest. Prevention Thoroughly cook foods, particularly meat, poultry, and gravies, to a safe internal temperature. Use a food thermometer to make sure.
Divide large amounts of food, such as roasts or big pots of chili or stew, into shallow containers and refrigerate immediately. It is OK to put hot foods directly in the refrigerator. Sources Contaminated food, especially undercooked ground beef, unpasteurized raw milk and juice, soft cheeses made from raw milk, and raw fruits and vegetables such as lettuce, other leafy greens, and sprouts.
Contaminated water, including drinking untreated water and swimming in contaminated water. Animals and their environment, particularly cows, sheep, and goats.
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