Safe food handling begins at the supermarket. Buy cold foods last, before you check out. Place meats in a plastic bag to prevent contact with other groceries, and head straight home for the refrigerator. Avoid produce that's bruised or damaged, and thoroughly wash all produce - including organics. When purchasing fresh cut produce, pick only items that are refrigerated or surrounded by ice. Juices and milk that have not been pasteurized should be refrigerated at all times, and can be dangerous for children, the elderly, and those with weakened immune systems. Perishables and leftovers should not be kept above 40 degrees for more than one hour. The meats you do not intend to cook in one or two days should be frozen. Thaw frozen meats in the refrigerator, not on the counter. Contrary to popular practices, it's not necessary to rinse raw poultry before cooking. Only cooking can kill bacteria, and rinsing can spread bacteria to nearby surfaces. When using a cooler, keep perishables separate from beverages to reduce the warming effects of the frequent lid-opening, and keep the cooler out of the sun. Pack moist towelettes for washing up if there is no source of clean, running water at your picnic site.
Don't ruin your summer vacation - play it safe!
Friday, July 23, 2010
Wednesday, July 14, 2010
Common Food Born Pathogens
Food borne illness is an ever-present threat that can be prevented with proper care and handling of food products. Chemicals, heavy metals, parasites, fungi, viruses and bacteria can cause food borne illness. Bacteria related food poisoning is the most common, but fewer than 20 of the many thousands of different bacteria actually are the culprits. Understand the difference between actual "food poisoning" and enteritis, and know the symptoms. Too many cases are mistaken for the flu, and the culprits go undetected. If a restaurant or deli is responsible for an illness, it should be reported to local health authorities.
Food poisoning is caused by ingesting food contaminated with “preformed” toxins. Although cooking destroys the bacteria, the toxin produced is heat stable and may not be destroyed. Staphylococcal food poisoning occurs most often in foods that require hand preparation, such as potato salad, ham salad and sandwich spreads. Sometimes these types of foods are left at room temperature for long periods of time, allowing the bacteria to grow and produce toxin. In food poisoning caused by microbial toxins, organisms that can continue to produce toxin may also be ingested with the toxins. Intestinal tissue damage, kidney and/or liver damage is due to the action of the toxin, so most cases of microbial food poisoning are intoxications rather than infections. Because the toxin is preformed, the onset of symptoms in intoxication is more rapid than in infection. Symptoms include abdominal pain, nausea, vomiting, and diarrhea, but usually not a fever. They appear 1 to 6 hours after ingestion and last up to 8 hours. Bacteria responsible for causing food poisoning include Staphylococcus aureus, Clostridium perfringens, Campylobacter, Clostridium botulinium (botulism), and Bacillus cereus.
Bacterial enteritis is an intestinal “infection,” not an intoxication, as is with food poisoning. The causative bacteria actually invade and damage the intestinal mucosa or deeper tissues. Enteritis that affects mainly the small intestine usually causes diarrhea. Because it is an infection, a fever is present. When the large intestine is affected, the result is often called “Dysentery”, a severe diarrhea and dehydration, and can cause systemic infections. Common enteritis’ include Salmonella, Listeria monocytogenes, Vibrio parahaemolyticus, and Entero-pathogenic Escherichia coli.
Food poisoning is caused by ingesting food contaminated with “preformed” toxins. Although cooking destroys the bacteria, the toxin produced is heat stable and may not be destroyed. Staphylococcal food poisoning occurs most often in foods that require hand preparation, such as potato salad, ham salad and sandwich spreads. Sometimes these types of foods are left at room temperature for long periods of time, allowing the bacteria to grow and produce toxin. In food poisoning caused by microbial toxins, organisms that can continue to produce toxin may also be ingested with the toxins. Intestinal tissue damage, kidney and/or liver damage is due to the action of the toxin, so most cases of microbial food poisoning are intoxications rather than infections. Because the toxin is preformed, the onset of symptoms in intoxication is more rapid than in infection. Symptoms include abdominal pain, nausea, vomiting, and diarrhea, but usually not a fever. They appear 1 to 6 hours after ingestion and last up to 8 hours. Bacteria responsible for causing food poisoning include Staphylococcus aureus, Clostridium perfringens, Campylobacter, Clostridium botulinium (botulism), and Bacillus cereus.
Bacterial enteritis is an intestinal “infection,” not an intoxication, as is with food poisoning. The causative bacteria actually invade and damage the intestinal mucosa or deeper tissues. Enteritis that affects mainly the small intestine usually causes diarrhea. Because it is an infection, a fever is present. When the large intestine is affected, the result is often called “Dysentery”, a severe diarrhea and dehydration, and can cause systemic infections. Common enteritis’ include Salmonella, Listeria monocytogenes, Vibrio parahaemolyticus, and Entero-pathogenic Escherichia coli.
Sunday, July 11, 2010
Vibrosis
Vibrio parahaemolyticus is found on sea foods, and requires the salt environment of sea water for growth and is very sensitive to cold and heat. Proper storage of perishable sea foods below 40 degrees F, and subsequent cooking and holding above 140 degrees F, will destroy the organisms. Food poisoning caused by this bacterium is a result of insufficient cooking and/or contamination of the cooked product by a raw product, followed by improper storage temperature. It is a major problem in Japan where many sea foods are consumed raw, such as Sushi. But it can be controlled with proper cooking and refrigeration. Symptoms of nausea, vomiting, diarrhea, and abdominal pain appear about 12 hrs. after ingestion and last 2-5 days. Sushi, anyone?
Wednesday, July 7, 2010
Salmonella
Health experts estimate the true prevalence of cases of Salmonella to exceed 2 million. Signs and symptoms include abdominal pain, fever, and diarrhea. They appear 8 - 48 hrs. after ingestion and lasts 1-4 days. It won't kill you, even though you wish it would. Many cases are mistaken for intestinal flu.
High protein foods such as meat, poultry, fish and eggs are most commonly associated with Salmonella. However, any food that becomes contaminated and is then held at improper temperatures can cause salmonellosis. Salmonella are destroyed at cooking temperatures above 150 degrees F. The major causes of salmonellosis are contamination of cooked foods and insufficient cooking. Contamination of cooked foods or raw produce occurs from contact with surfaces or utensils that were not properly washed after use with raw products. Always use a bleach solution on cutting boards and utensils. If Salmonella is present on raw or cooked foods, its growth can be controlled by refrigeration below 40 degrees F.
High protein foods such as meat, poultry, fish and eggs are most commonly associated with Salmonella. However, any food that becomes contaminated and is then held at improper temperatures can cause salmonellosis. Salmonella are destroyed at cooking temperatures above 150 degrees F. The major causes of salmonellosis are contamination of cooked foods and insufficient cooking. Contamination of cooked foods or raw produce occurs from contact with surfaces or utensils that were not properly washed after use with raw products. Always use a bleach solution on cutting boards and utensils. If Salmonella is present on raw or cooked foods, its growth can be controlled by refrigeration below 40 degrees F.
Monday, July 5, 2010
Listeria Is On The Move
Before the 1980's most problems associated with disease caused by Listeria were related to cattle or sheep. This changed with food related outbreaks in Nova Scotia, Massachusetts, California and Texas. As a result of its widespread distribution in the environment, its ability to survive long periods of time under adverse conditions, and its ability to grow at refrigeration temperatures, Listeria, a form of meningitis, is now recognized as an important food-borne pathogen. There have been cases where health inspectors inadvertently carried the pathogen from one meat packing plant to another on their shoes. Listeria bacteria can also be transmitted through soil and water. A person can also ingest listeria by eating certain foods, such as deli meats and cold cuts, soft-ripened cheese, milk, undercooked chicken, uncooked hot dogs, shellfish, and coleslaw made from contaminated cabbage. Many cases of infection, however, have no identifiable source.
Immunocompromised humans such as pregnant women or the elderly are highly susceptible to virulent Listeria. It has become a leading cause of infection in kidney transplant patients. The bacillus can also cross the placenta of pregnant women and cause abortion, still birth, neonatal death, and birth defects. In humans, ingestion of the bacteria may be marked by a flu-like illness or symptoms may be so mild that they go unnoticed. Symptoms include fever and chills, headache, upset stomach and vomiting. A carrier state can develop. Death is rare in healthy adults; however, the mortality rate may approximate 30 percent in those with weak immune systems, new born or very young.
As mentioned earlier Listeria monocytogenes is a special problem since it can survive adverse conditions. It can be in a variety of raw foods as well as in processed foods and foods made from unpasteurized milk. It can grow in a pH range of 5.0-9.5 in good growth medium. The organism has survived the pH 5 environment of cottage cheese and ripening cheddar. It is salt tolerant surviving concentrations as high as 30.5 percent for 100 days at 39.2 degrees F, but only 5 days if held at 98.6 degrees F.
The key point is that refrigeration temperatures do not stop growth of Listeria. It is capable of doubling in numbers every 1.5 days at 39.5 degrees F. Since high heat, greater than 170 degrees F, will inactivate the Listeria organisms, post-process contamination from environmental sources then becomes a critical control point for many foods. To reduce your risk:
Immunocompromised humans such as pregnant women or the elderly are highly susceptible to virulent Listeria. It has become a leading cause of infection in kidney transplant patients. The bacillus can also cross the placenta of pregnant women and cause abortion, still birth, neonatal death, and birth defects. In humans, ingestion of the bacteria may be marked by a flu-like illness or symptoms may be so mild that they go unnoticed. Symptoms include fever and chills, headache, upset stomach and vomiting. A carrier state can develop. Death is rare in healthy adults; however, the mortality rate may approximate 30 percent in those with weak immune systems, new born or very young.
As mentioned earlier Listeria monocytogenes is a special problem since it can survive adverse conditions. It can be in a variety of raw foods as well as in processed foods and foods made from unpasteurized milk. It can grow in a pH range of 5.0-9.5 in good growth medium. The organism has survived the pH 5 environment of cottage cheese and ripening cheddar. It is salt tolerant surviving concentrations as high as 30.5 percent for 100 days at 39.2 degrees F, but only 5 days if held at 98.6 degrees F.
The key point is that refrigeration temperatures do not stop growth of Listeria. It is capable of doubling in numbers every 1.5 days at 39.5 degrees F. Since high heat, greater than 170 degrees F, will inactivate the Listeria organisms, post-process contamination from environmental sources then becomes a critical control point for many foods. To reduce your risk:
- Use precooked and ready-to-eat foods as soon as you can
- Avoid raw milk and raw milk products
- Heat ready-to-eat foods and leftovers until they are steaming hot
- Wash fresh fruits and vegetables
- Avoid rare meat and seafood
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