Are There Dangerous Germs Lurking in Your Kitchen?

By Lisa YakasMicrobiologist and manager of NSF International’s Home Product Certification Program A new study reveals the surprising places where germs and bacteria hide and why proper cleaning is essential.

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Over the past few years, there has been an increase in the number of Americans who prepare and cook food at home. While many turned to cooking at home as a cost-cutting measure during the Great Recession, for many it is a trend that is here to stay. In fact, a recent Harris Interactive Poll reveals that 71% of Americans are still cooking at home to save money.

Aside from the financial motivation, many Americans are cooking at home because they believe it is a healthier choice than eating out. Cooking in your own kitchen provides a sense of control – you know what ingredients are going into the meal you’re preparing. However, you may not know everything that is going into your next meal – and what you don’t know might actually hurt you and your family. 

Studies have shown that more than 20% of foodborne illness outbreaks result from food that was consumed in the home. NSF International food-safety experts point to a number of contributing factors, including improper food storage, handling and preparation.  

A global public health organization, NSF International has a long history in working to help ensure safe design and cleaning of equipment or appliances used in food preparation. NSF’s Commercial Food Equipment Program commenced in the 1940s, focusing on items used in restaurants. NSF’s Home Product Certification Program began in 2012, addressing kitchen appliances and tools used in the home. In addition to evaluating material and design, the program evaluates manufacturers’ cleaning instructions to help prevent equipment from harboring pathogens that can cause foodborne illness.  

Because of NSF’s role in evaluating the “cleanability” of common kitchen tools and appliances used in the home, the NSF microbiologists conducting the 2013 NSF International Germ Study analyzed 14 common kitchen items for the presence of four different types of microorganisms: E. coli, Salmonella, Listeria, yeast and mold. All of these can potentially be harmful and especially dangerous to at-risk populations, including the elderly, pregnant women, children and those with compromised immune systems, resulting in anything from allergic reactions to diarrhea and abdominal pain to fever and even death in the most severe cases. 

The study found that some common kitchen appliances, utensils and tools are, in fact, contaminated with harmful bacteria and germs. All of the kitchenware tested revealed the presence of one or more of these microorganisms. Some of the “germiest” items that have the potential to cause illness included the refrigerator vegetable compartment, refrigerator meat compartment, blender gasket, can opener, rubber spatula, and food storage containers with rubber seals. Here are some things to consider before whipping up your next meal at home:

Perception does not match reality. As part of the study, NSF asked volunteers what they thought were the “germiest” items in the kitchen. Those families cited the microwave keypad, can opener and refrigerator meat compartment as the germiest items. However, testing revealed the refrigerator water dispenser, spatula and blender gasket actually contained the most germs. Many volunteers didn’t consider their blender a germy item, but in reality, it was the third germiest item in the kitchen. The refrigerator water dispenser didn’t make their list at all, but both the water and ice dispensers proved to be areas of concern for yeast and mold, which are a problem for those with allergies. People’s perceptions of what is dirty impacts their cleaning behavior, so be sure to add these kitchen items to your weekly list of places to clean.

Below is a comparison of what were perceived to be the germiest items in the kitchen versus the actual germiest items (ranked from highest to lowest in germ count):

Be aware of potential problem areas and learn to prevent contamination. Volunteers thought that the vegetable and meat compartments would rank among the dirtiest items in the kitchen and they were right. However, what many volunteers may not have realized is that the types of germs found in these areas were harmful (such as E. coli and Salmonella) and that they may come into direct contact with food, especially raw produce. What we learned is that: 1) it isn’t enough to wash your produce, you must also wash the areas where the produce is stored; and 2) storing clean and unwashed produce together can be problematic. 

Fresh food can have a longer shelf life. Yeast and mold are not only among the most common microorganisms found in the kitchen, but they are also among the biggest culprits of food spoilage. For example, storing food in contaminated storage containers may lead to food spoiling at a faster rate. Thoroughly cleaning kitchen items can help keep foods fresher for longer (and lower your weekly grocery bill).

Read manuals carefully for cleaning instructions. The answer to keeping germs at bay in the kitchen is not a complicated one: Follow the manufacturer’s directions when it comes to cleaning and sanitizing kitchen tools and appliances. For example, to properly clean a blender you need to disassemble it and pull the gasket apart from the base and then wash it with warm soapy water. Refrigerator vegetable and meat compartments need to be cleaned and sanitized regularly since they often come in closest contact with foods and can cause cross-contamination if not properly cleaned. Like all kitchen tools, can openers should be washed and sanitized after each use. Rubber spatulas that are detachable should be pulled apart from the handle to be cleaned and dried. To protect food when it’s being stored, thoroughly clean storage containers and lids, especially those with rubber seals. Be sure to thoroughly dry all components before reassembling a kitchen product so you’re not creating an ideal environment for yeast and mold to grow.

Be an educated consumer. If you’re in the market for new kitchenware, look for the NSF Certified for Home Use seal. It verifies that durability, performance and material safety requirements are met. It also verifies the effectiveness of the manufacturers’ cleaning instructions. 

Everyone loves a home-cooked meal, so it’s important to be aware of germs that may be present in your kitchen – and to take the necessary precautions to ensure your kitchen is as safe as possible. 

More cleaning tips can be found at NSF.org/Consumer (Home & Family section).