April 18, 2014
News Review From Harvard Medical School -- Foodborne Illness Stable; Salmonella Down
Though salmonella rates fell, cases of food poisoning overall have remained steady in recent years, U.S. health officials say. The new report comes from the Centers for Disease Control and Prevention (CDC). It includes cases in 10 states. The CDC's reporting system confirmed 19,000 cases of foodborne illness in these states in 2013. About 4,200 people required a hospital stay. Eighty people died. Salmonella alone caused 38% of the confirmed cases. Campylobacter was close behind, with 35% of the cases. Salmonella bacteria caused 15 cases per 100,000 people. That's down 9% from 2010-2012. The CDC hopes to cut the rate to 11.4 by 2020. Campylobacter rates have been stable for the last 5 years. Vibrio bacteria are a lesser known cause of illness. These bacteria, found in shellfish, produce an infectious toxin. Vibrio accounts for only about 1% of foodborne illness. However, rates increased by one-third in just the last 3 years, the CDC said. The journal Morbidity and Mortality Weekly Report published the study. HealthDay News wrote about it April 17.
By Howard LeWine, M.D.
Harvard Medical School
What Is the Doctor's Reaction?
This report only tells us about trends in confirmed cases of food-related infections. It covers only those caused by certain bacteria and parasites. But that's only the "tip of the iceberg."
For every case of foodborne illness confirmed by laboratory culture, 30 more cases don't get cultured. Many more people are affected but never get tested. The Centers for Disease Control and Prevention (CDC) estimates that 1 American in every 6 contracts a foodborne illness each year. These illnesses cause 128,000 hospital stays and 3,000 deaths per year.
The Foodborne Diseases Active Surveillance Network (FoodNet) regularly collects information on laboratory-confirmed infections caused by nine different germs. FoodNet works with 10 states that have a total of 48 million people.
Seven of the germs are bacteria and 2 are parasites. Of these 9, salmonella and Campylobacter bacteria together cause 73% of the cases FoodNet tracks.
But FoodNet does not track the most common cause of foodborne illness. That dubious honor goes to norovirus (Norwalk-like viruses). The virus causes an estimated 58% of all food-related illness.
Norovirus is highly contagious. As few as 10 viral particles can cause infection. Of course, it spreads through contaminated food. But it also spreads easily from person to person.
Not everyone who comes in contact with any of these germs gets sick. For those who do, the symptoms are usually very similar. They include crampy pain in the belly, nausea, vomiting and diarrhea. Most people recover within a few days.
Norovirus infections can lead to dehydration. Otherwise, severe effects are very rare. Some of the other infections have the potential to cause fever, bloody diarrhea and kidney failure. Infants, older people, pregnant women and those with weakened immune systems have a higher risk of these more serious problems.
What Changes Can I Make Now?
There's a lot you can do to prevent food poisoning.
- Buy your produce and poultry from clean, reliable sources.
- Be sure all dairy products and juices are pasteurized.
- Once at home, bring your bundles in and refrigerate or freeze perishables right away.
- Keep meat, poultry, seafood and eggs separate from each other and other food items in the refrigerator.
- Thaw foods in the refrigerator, not on the counter or in the sink.
Preparing foods before cooking or eating:
- Wash hands with warm water and soap for 20 seconds before preparing food.
- Wash fruits and vegetables under running water just before eating, cutting or cooking.
- Wash produce even if you are going to just peel it or slice it. The knife can transfer bacteria from the outside to the inside as it slices through.
- Remove the outer leaves of leafy vegetables before preparing.
- Use separate surfaces and utensils when preparing raw meat or eggs.
- Always use a food thermometer to make sure you have cooked food to these temperatures:
- 145° F for meat (whole cuts of pork, veal, lamb and beef)
- 160° for ground meat (beef, veal, lamb and pork
- 165° for poultry (including ground turkey and chicken)
- Cook egg yolks until they are firm, not runny.
- When reheating, make sure that foods reach 165° F. Soups should boil.
Cleaning up after eating:
- Wash surfaces or utensils after each use.
- Refrigerate or freeze leftovers within 2 hours of cooking.
What Can I Expect Looking to the Future?
There were fewer cases of salmonella infection last year. But just one outbreak could send the numbers much higher this year or next. Overall, the rates of foodborne illnesses have not changed much in the last several years.
Food safety must continue to be a public health priority. But even if we could afford to double our efforts to monitor and enforce food safety, risk of foodborne illness will always exist. That's why prevention at home is so important.