Bacterial Cross-Contamination: All You Need to Know
By Katey Davidson
Each year, an estimated 600 million people worldwide experience a foodborne illness.
While there are many causes, a major and preventable one is cross-contamination.
This article explains all you need to know about cross-contamination, including how to avoid it.
What is Cross-Contamination?
Bacterial cross-contamination is defined as the transfer of bacteria or other microorganisms from one substance to another.
Other types of cross-contamination include the transfer of food allergens, chemicals, or toxins — though these are not the focus of this article.
Many people assume that foodborne illness is mostly caused by eating at restaurants, but there are many ways in which cross-contamination can occur, including:
- primary food production — from plants and animals on farms
- during harvest or slaughter
- secondary food production — including food processing and manufacturing
- transportation of food
- storage of food
- distribution of food — grocery stores, farmer's markets, and more
- food preparation and serving — at home, restaurants, and other foodservice operations
Given that there are many points at which cross-contamination can occur, it's important to learn about the different types and how you can prevent it.
Cross-contamination is defined as the transfer of bacteria or other microorganisms from one substance to another. It can happen during any stage of food production.
Types of Cross-Contamination
There are three main types of cross-contamination: food-to-food, equipment-to-food, and people-to-food.
Adding contaminated foods to non-contaminated foods results in food-to-food cross-contamination. This allows harmful bacteria to spread and populate.
Raw, undercooked, or improperly washed food can harbor large amounts of bacteria, such as Salmonella, Clostridium perfringens, Campylobacter, Staphylococcus aureus, E. coli, and Listeria monocytogenes — all of which can harm your health if consumed.
Foods that pose the highest risk of bacterial contamination include leafy greens, bean sprouts, leftover rice, unpasteurized milk, soft cheeses, and deli meats, as well as raw eggs, poultry, meat, and seafood.
For example, adding unwashed, contaminated lettuce to a fresh salad can contaminate the other ingredients. This was the case in a 2006 E. Coli outbreak that affected 71 Taco Bell customers.
What's more, leftovers kept in the fridge too long can result in bacterial overgrowth. Therefore, eat leftovers within 3–4 days and cook them to proper temperatures. If you plan to mix leftovers with other foods, the new meal should not be stored again as leftovers.
Equipment-to-food is one of the most common yet unrecognized types of cross-contamination.
Bacteria can survive for long periods on surfaces like countertops, utensils, cutting boards, storage containers, and food manufacturing equipment.
When equipment is not washed properly or unknowingly contaminated with bacteria, it can transfer large volumes of harmful bacteria to food. This can happen at any point during food production — both at home and in food manufacturing.
For example, a 2008 incident at a Canadian-based sliced meat company resulted in the death of 22 customers due to listeria-contaminated meat slicers.
A common example of this occurring at home is using the same cutting board and knife to cut raw meat and vegetables, which can be harmful if the vegetables are then consumed raw.
One study found that older participants were less likely to use soap and water to clean their cutting boards after working with raw meat, while younger people weren't aware of the risks of cross-contamination. Thus, more food safety education seems to be needed across all age groups.
Finally, improper food preservation techniques can lead to cross-contamination. In 2015, home-canned potatoes used in a potato salad made 22 potluck attendees sick with botulism due to improper canning practices.
For example, a person may cough into their hand or touch raw poultry and continue to prepare a meal without washing their hands in between.
In a 2019 study in 190 adults, only 58% of participants reported washing their hands before cooking or preparing food, while only 48% said they washed their hands after sneezing or coughing.
Other common examples include using a cellphone that's loaded with bacteria while cooking or wiping your hands with a dirty apron or towel. These practices may contaminate your hands and spread bacteria to food or equipment.
Although this poses a concern, a 2015 meta-analysis found that food safety education both in the home and at work can significantly lower the risk of cross-contamination and unsafe food practices.
By far, the most effective way to reduce the risk of cross-contamination is to properly wash your hands with soap and water for at least 20 seconds.
There are three main types of cross-contamination: food-to-food, equipment-to-food, and people-to-food. In each type, bacteria are transferred from a contaminated source to uncontaminated food.
The side effects of cross-contamination can be mild to severe.
Minor side effects include upset stomach, loss of appetite, headache, nausea, and diarrhea. Usually, these side effects present within 24 hours, although they can appear weeks after exposure, making it difficult to determine the specific cause.
In cases involving vomiting or diarrhea, it's important to rehydrate properly — for example with a sports beverage — to restore hydration, blood sugar, and electrolyte levels.
Severe side effects include diarrhea for more than 3 days, bloody stools, fever, dehydration, organ failure, and even death.
Seek immediate medical attention if your side effects worsen or last longer than 1–2 days, as well as if you're considered to be in an at-risk population.
Side effects of cross-contamination range from stomach upset to more severe aftereffects, including dehydration, organ failure, and even death.
Who is at Risk?
Everyone is at risk of becoming sick from cross-contamination.
However, certain groups are at a much higher risk, including:
- pregnant women
- children under the age of 5
- adults over the age of 65
- those with weakened immune systems — for example, people with HIV/AIDS, uncontrolled diabetes, or cancer
Considering these groups make up a large segment of the population, it's crucial to practice safe food handling when at home or working in a foodservice establishment.
Anyone is at risk of becoming sick from cross-contamination. However, certain groups, including pregnant women, children, older adults, and those with weakened immune systems, are at the highest risk.
How to Avoid Cross-Contamination
There are many ways to avoid cross-contamination.
Food Purchasing and Storage
- Avoid purchasing food close to its expiration date, unless you intend to eat it right away.
- Store raw meat in a sealed container or plastic bag on the bottom shelf of the refrigerator to prevent juices from leaking onto other foods.
- Use separate grocery bags for raw meat and eggs.
- Use refrigerated leftover food within 2–3 days and cook it to proper temperatures.
- Wash your hands with soap and water for at least 20 seconds after touching raw meat, petting an animal, using the washroom, coughing or sneezing, using your phone, or related instances.
- Wash your utensils, countertops, cutting boards, and other surfaces with soap and warm water, especially when handling raw meat.
- Use separate cutting boards for meat and vegetables.
- Use clean sponges and dishcloths.
- Cook foods to their proper temperatures by using a food thermometer.
Finally, be sure to stay up to date with food recalls by visiting the website of your country's food and disease control board, such as the Centers for Disease Control and Prevention (CDC) in the United States.
Proper food safety practices can significantly reduce your risk of cross-contamination. Thoroughly wash your hands and surfaces, properly store foods, and stay up to date with food recalls.
The Bottom Line
Bacterial cross-contamination can have serious and even fatal consequences, but thankfully, it's easy to prevent.
Practice good hygiene, wash and sanitize your equipment, and properly store and serve food to prevent cross-contamination. Plus, it's a good idea to stay up to date with food recalls, which are available online.
By practicing safe food handling, you can protect yourself and others from getting sick.
EcoWatch Daily Newsletter
By Michael Svoboda
The enduring pandemic will make conventional forms of travel difficult if not impossible this summer. As a result, many will consider virtual alternatives for their vacations, including one of the oldest forms of virtual reality – books.
Watchdog Accuses Trump's NOAA of 'Choosing Extinction' for Right Whales by Hiding Scientific Evidence
By Julia Conley
As the North Atlantic right whale was placed on the International Union for Conservation of Nature's list of critically endangered species Thursday, environmental protection groups accusing the U.S. government of bowing to fishing and fossil fuel industry pressure to downplay the threat and failing to enact common-sense restrictions to protect the animals.
- Lemurs and Northern Right Whales Near Brink of Extinction ... ›
- Trump Administration Approves Harmful Seismic Blasting in Atlantic ... ›
By Beth Ann Mayer
Since even moderate-intensity workouts offer a slew of benefits, walking is a good choice for people looking to stay healthy.
How to Rock Your Walk<p>Walking isn't just fun and healthy. It's accessible.</p><p>"Walking is cheap," says Dr. John Paul H. Rue, a sports medicine doctor at <a href="https://mdmercy.com/" target="_blank">Mercy Medical Center in Baltimore</a>. "You can do it anywhere at any time; [it] requires little to no special equipment and has many of the same cardio benefits as running or other more intense workouts."</p><p>Want to up your walking game? Try the tips below.</p>
Use Hand Weights<p>Cardio and strength training can go hand-in-hand when you add weights to your walk.</p><p>A <a href="https://journals.lww.com/acsm-msse/Fulltext/2019/03000/Associations_of_Resistance_Exercise_with.14.aspx" target="_blank">2019 study</a> found that weight training is good for your heart, and <a href="https://www.mayoclinicproceedings.org/article/S0025-6196(17)30167-2/abstract" target="_blank">research</a> shows it reduces the risk of developing a <a href="https://www.healthline.com/health/nutrition-metabolism-disorders" target="_blank">metabolic disorder</a> by 17 percent. People with metabolic disorders have a higher chance of being diagnosed with high cholesterol, high blood pressure, and diabetes.</p><p>Rue suggests not carrying weights for your entire walk.</p><p>"Hand weights can give you an added level of energy burning, but you have to be careful with these because carrying [them] over a long period of time or while walking could actually lead to some overuse injuries," he says.</p>
Make It a Circuit<p>As another option, consider doing a circuit. First, put a pair of dumbbells on your lawn or somewhere in your home. Walk around the block once, then stop and do some bicep curls and tricep lifts before walking around the block again.</p><p>Rue recommends <a href="https://www.healthline.com/health/exercise-fitness/running-with-weights" target="_blank">avoiding ankle weights</a> during cardio workouts, as they force you to use your quadriceps rather than hamstrings. They can also cause muscle imbalance, according to the <a href="https://www.health.harvard.edu/staying-healthy/wearable-weights-how-they-can-help-or-hurt" target="_blank">Harvard Health Letter</a>.</p>
Find a Fitness Trail<p>Strength training isn't limited to weights. You can get stronger by <a href="https://www.healthline.com/health/bodyweight-workout" target="_blank">simply using your body</a>.</p><p>Often found at parks, fitness trails are obstacle courses with equipment for pullups, pushups, rowing, and stretches to build upper and lower body strength.</p><p>Try searching "fitness trails near me" online, checking out your local parks and recreation website, or calling the municipal office to <a href="https://calisthenics-parks.com/" target="_blank">find one</a>.</p>
Recruit a Friend<p>People who workout together stay healthy together.</p><p><a href="https://bmcgeriatr.biomedcentral.com/articles/10.1186/s12877-017-0584-3" target="_blank">One study</a> showed that older adults who exercised with a group improved or maintained their functional health and enjoyed their lives more.</p><p>Enlist the help of a walking buddy with a regimen you aspire to have. If you don't know anyone in your area, apps like <a href="https://www.strava.com/" target="_blank">Strava</a> have social networking features so you can get support from fellow exercisers.</p>
Try Meditation<p>According to the <a href="https://www.nccih.nih.gov/research/statistics/nhis/2017" target="_blank">2017 National Health Interview Survey</a>, published by the National Institutes of Health, meditation is on the rise, and for good reason.</p><p>Researchers <a href="https://pubmed.ncbi.nlm.nih.gov/29616846/" target="_blank">found</a> that mind-body relaxation practices can regulate inflammation, <a href="https://www.healthline.com/health/biological-rhythms" target="_blank">circadian rhythms</a>, and <a href="https://www.healthline.com/health/glucose" target="_blank">glucose</a> metabolism, as well as lower <a href="https://www.healthline.com/health/high-blood-pressure-hypertension" target="_blank">blood pressure</a>.</p><p>"Any form of exercise can be turned into a meditation of some type, either by the surroundings you are walking in, like a park or trail, or by blocking out the outside world with music on your headphones," Rue says.</p><p>You can also play a podcast or download an app like <a href="https://www.headspace.com/headspace-meditation-app" target="_blank">Headspace</a> that has a library of guided meditations to practice while you walk.</p>
Do Fartlek Walks<p>Typically used in running, fartlek intervals alternate periods of increased and decreased speed. These are <a href="https://www.healthline.com/nutrition/benefits-of-hiit" target="_blank">high-intensity interval training (HIIT)</a> workouts, which allow exercisers to accomplish more in less time.</p><p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154075" target="_blank">One study</a> showed that 10-minute interval training improved <a href="https://www.healthline.com/health/metabolic-syndrome" target="_blank">cardiometabolic</a> health, or lowered the risk of heart disease, stroke, and diabetes, just as well as working out at a continuous pace for 50 minutes.</p><p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111489" target="_blank">Research</a> also shows that HIIT workouts increase muscle <a href="https://www.healthline.com/health/fast-twitch-muscles" target="_blank">oxidative</a> capacity, or the ability to use oxygen. To do a fartlek walk, try walking at an increased pace for 3 minutes, slow down for 2 minutes, and repeat.</p>
Gradually Increase Pace<p>A faster walking pace is associated with a lower risk of <a href="https://www.healthline.com/health/copd" target="_blank">chronic obstructive pulmonary disease (COPD)</a> and respiratory diseases, according to a <a href="https://pubmed.ncbi.nlm.nih.gov/30303933/" target="_blank">2019 study</a>.</p><p>Still, it's best not to go from a stroll to an Olympic-worthy power walk in a day. Instead, increase your pace gradually to prevent injury.</p><p>"Start by walking at a brisk pace for about 10 minutes per day, 3 to 5 days per week," Rue says. "Once you've done this for a few weeks, increase your time by 5 to 10 minutes per day until you get to 30 minutes."</p>
Add Stairs<p>You've likely heard that taking the stairs instead of an elevator is a way to add more movement into your daily routine. It's also a way to step up your walking. Stair climbing has been shown to <a href="https://www.sciencedirect.com/science/article/pii/S2211335519301123?via%3Dihub" target="_blank">decrease the risk of mortality</a> and can easily add a bit more challenge to your walk.</p><p>If you don't have stairs in your home, you can often find them outside a local municipal building, train station, or at a high school stadium.</p>
Is Your Walk a True Cardio Workout?<p>Not all walks are equal. A walk that's too leisurely may not provide enough burn to qualify as cardio. To see if you're getting a good workout, try to <a href="https://www.healthline.com/health/how-to-check-heart-rate" target="_blank">measure your heart rate</a> using a monitor.</p><p>"A target goal for a good walking workout heart rate is about 50 to 70 percent of your maximum heart rate," Rue says, adding that maximum heart rate is <a href="https://www.healthline.com/health/fitness-exercise/fat-burning-heart-rate" target="_blank">typically calculated</a> by 220 beats per minute minus your age.</p><p>You can also monitor how easily you can carry on a conversation while you walk to gauge your heart rate.</p><p>"If you can walk and carry on a normal conversation, that's probably a lower intensity walk," says Rue. "If you are slightly breathless but can still have a conversation, that's probably a moderate workout. If you are out of breath and can't talk normally, that's a vigorous workout."</p>
Takeaway<p>By shaking up your routine, you can add excitement to your workout and reap even more rewards than a basic walk provides. Increasing the pace and intensity of a workout will make it more effective.</p><p>Simply pick your favorite variation to add some spice to your next walk.</p>
- Should I Exercise During the Coronavirus Pandemic? Experts ... ›
- If Meditation Is Not Your Thing, Try a Walk in the Woods - EcoWatch ›
In Major Win for Indigenous Rights, Supreme Court Rules Much of Eastern Oklahoma Is Still a Reservation
Much of Eastern Oklahoma, including most of Tulsa, remains an Indian reservation, the Supreme Court ruled on Thursday.
- Federal Judge Orders Trump Admin to Give Native Americans Their ... ›
- Police Were Ready to Shoot Indigenous Pipeline Protesters in ... ›
- Climate Justice, Indigenous Rights Advocates Rally for Wet'suwet'en ... ›
By Tiffany Means
Summer and fall are great seasons to enjoy the outdoors. But if you're already spending extra time outside because of the COVID-19 pandemic, you may be out of ideas on how to make fresh-air activities feel special. Here are a few suggestions to keep both adults and children entertained and educated in the months ahead, many of which can be done from the comfort of one's home or backyard.
The coronavirus may linger in the air in crowded indoor spaces, spreading from one person to the next, the World Health Organization acknowledged on Thursday, as The New York Times reported. The announcement came just days after 239 scientists wrote a letter urging the WHO to consider that the novel coronavirus is lingering in indoor spaces and infecting people, as EcoWatch reported.
- Airborne Coronavirus Transmission Must Be Taken Seriously, 239 ... ›
- Trump Halts WHO Funding Amidst Criticism of His Own Coronavirus ... ›
- Here's Why COVID-19 Can Spread So Easily at Gyms and Fitness ... ›
- Is the New Coronavirus Airborne? A Study From China Finds Evidence ›
By Angela Nicoletti
The eastern slopes of the Andes Mountains in central Perú are among the most remote places in the world.
- Global Frog Pandemic May Become Even Deadlier as Strains ... ›
- New Species of Diamond Frog Discovered in Remote Pocket of ... ›
- Frogs Are on the Verge of Mass Extinction, Scientists Say - EcoWatch ›