Food Safety Magazine

News | August 9, 2013

NSF Int'l Study Finds Kitchen Tools Hold onto Foodborne Pathogens

By Staff


NSF International's Applied Research Center (ARC) has released the 2013 NSF International Household Germ Study, revealing that many common kitchen items harbor unsafe levels of E. coli, Salmonella, Listeria, yeast and mold. NSF International scientists point to a number of contributing factors —  including improper food storage, handling, preparation and cleaning — which may help explain why more than 20% of foodborne illness outbreaks result from food consumed in the home.

NSF International is an Ann Arbor, MI-based global public health and safety organization. NSF's Applied Research Center conducts original research and development projects for academia, industry, and regulatory bodies to further public health and safety.

The NSF microbiologists conducting the germ study analyzed 14 common kitchen items for the presence of four different types of microorganisms:  E. coli, Salmonella, yeast and mold, and Listeria. The study found that many of these common kitchen appliances and tools used to prepare food do indeed harbor pathogens that can cause foodborne illness:

  • Refrigerator vegetable compartment: Salmonella, Listeria, yeast and mold
  • Refrigerator meat compartment: Salmonella, E. coli, yeast and mold
  • Blender gasket: Salmonella, E. coli, yeast and mold
  • Can opener: Salmonella, E. coli, yeast and mold
  • Rubber spatula: E. coli, yeast and mold
  • Food storage container with rubber seal: Salmonella, yeast and mold


It is NSF's hope that the information gained from this study will further underscore the importance of properly maintaining and cleaning these items, especially those that we don't always think to disassemble and clean such as the blender gasket.

"Consumers are increasingly concerned about the safety and quality of their food but often don't realize that they may be the cause of foodborne illness in their own homes, due to improper cleaning of kitchenware and appliances. As a NSF microbiologist, I was surprised to learn that most people know what items carry germs, but they still didn't clean them properly. Products that come in direct contact with food must be designed and maintained properly to prevent germ growth. The performance, quality, material safety and cleanability of home products all are important for food safety," said Rob Donofrio, Ph.D., director of NSF International's Applied Research Center.

NSF Home Product Certification Program
"Young children, the elderly and those with weakened immune systems are particularly vulnerable to foodborne illness," said Donofrio. "Concerned consumers can look for the NSF Home Product Certification mark on products to ensure items can be cleaned correctly when following the manufacturer's instructions to prevent harboring germs."

Perception vs. Reality:  Are We Unknowingly Making Ourselves and Others Sick?
Importantly, while germ study volunteers correctly identified items that they thought would harbor the most germs, they are not always cleaning them sufficiently to prevent illness. The following is a list of the items that were perceived by volunteers to be the "germiest" versus the actual "germiest" items (ranked from highest to lowest in germ count):

Perceived:
1. Microwave keypad
2. Can opener
3. Refrigerator meat compartment
4. Refrigerator vegetable compartment
5. Flatware storage tray
6. Knife block
7. Pizza cutter
8. Rubber spatula
9. Refrigerator insulating seal
10. Ice dispenser     

Reality:
1. Refrigerator water dispenser
2. Rubber spatula
3. Blender
4. Refrigerator vegetable compartment
5. Refrigerator ice dispenser
6. Refrigerator meat compartment
7. Knife block
8. Food storage container with rubber seal
9. Can opener
10. Refrigerator insulating seal

Germs found on these everyday kitchen appliances and tools can easily come in direct contact with food, especially raw produce, meat, poultry, seafood and ready-to-eat food. The study identified where the germs are located in the average home kitchen and, more importantly, how people can better protect against foodborne illness. The key is to be aware of where the 'hot spots' are in your home and clean correctly and regularly to help prevent germ accumulation.

"What's important to remember is the science behind the study. Germs exist everywhere and while not all germs are 'bad,' our goal is to educate the public about how they can help keep their families healthy," said Donofrio.