Grocery Stores: Does Enhanced Sanitizing Kill Germs?

Bring a Sanitizing Wipe – Some Surfaces 100x to 1000x dirtier in the evenings.

Written By: Rob Gabriele | Updated September 28, 2023

Even before a highly contagious virus reached America’s shores and raised sanitation concerns, many of us were aware that grocery stores were full of germs. In some places, that truth can be impossible to ignore. Whether or not you’re the type of person who constantly thinks about microbes lurking on high-touch public surfaces, it’s important to consider the ramifications of picking up germs from strangers.

The last time we examined germs was in our home bathrooms – a different environment, but one we were curious to compare with the more public atmosphere of grocery stores. Our new study below expands on our prior research by providing a closer look at the growth of germs in grocery stores throughout the day, looking to see how germs may grow on surfaces in stores from the beginning of the day to the end. We tested high-touch surfaces in multiple stores in the morning and evening to measure changes in germ levels. We also took our research a step further by surveying Americans about changes in their grocery shopping habits and how they feel about contactless shopping methods going forward.

Key Findings

  • High-touch grocery store surfaces can be over 1,000 times as germy at the end of the shopping day compared to the beginning, with refrigerator door handles being the worst offenders.
  • Shopping cart handles are remarkably clean when compared to other high-touch surfaces like refrigerator handles, and grow germs at a much less alarming rate.
  • 45% of Americans who’d shopped for groceries online during the pandemic had never done so before. Nearly 90% of them had planned to integrate online grocery shopping into their normal lives.

The Best Time to Grocery Shop

With a steady stream of people touching the same things throughout the day, grime both visible and not can pile up quickly. The first part of our study focused on the germiness of refrigerator handles, shopping cart handles, and self-checkout touch screens. Take a look at how these surfaces fared from morning to night.

We found a marked increase between germ levels from morning to evening. We also determined that the dirtiest surface you can touch in a grocery store is the refrigerator door handle, and the self-checkout touch screen is the next germiest. By a significant margin, the least dirty is a shopping cart handle.

Startlingly, our study concluded that high-touch grocery store surfaces can be over 1,000 times dirtier at the end of the shopping day when compared to the beginning of the day. Even when stores – like those we studied – implement extra sanitation procedures, many more bacteria inhabit surfaces after an entire day of shopping activity.

Therefore, the best time to go grocery shopping is when the store first opens its doors, especially on a slow Monday morning. Everything has been sanitized by the night-time cleaning crew, and less people are usually in the store early in the day. Grocery stores are the dirtiest on high-traffic days and near closing time. Shop safer and healthier by avoiding stores later in the day and on crowded Saturdays and Sundays.

The Dirty Truth About Grocery Stores

To help you visualize just how dirty a grocery store can be, we compared three store surfaces to areas of your home that you come into contact with every day using results from the NSF International Household Germ Study.

Grocery store refrigerator handles turned out to contain more than 20 times the amount of bacteria that a typical household bathroom faucet bears, and self-checkout touchscreens were nearly 10 times as dirty as the average household toilet seat. Perhaps the most surprising result from our study, though, is the apparent efficacy of shopping cart sanitation policies. As many stores continue implementing rigorous cart sanitation, our analysis returned a lower germ count on shopping carts than for most household items and surfaces – somewhere between the average amount found on your personal computer keyboard and your steering wheel.

Understanding how dirty a grocery store can be is simply the first step to learning how to better protect yourself from germs that cause illness. Consider the following safety precautions recommended by the Food and Drug Administration (FDA) to minimize your exposure to germs, bacteria, and viruses:

  • Sanitize your hands after touching surfaces
  • Wear a mask over your mouth and nose
  • Wash reusable bags after every use
  • Wash your hands after shopping and after putting groceries away
  • Wipe down handles and touch screens with sanitizing wipes before use

Ordering online and taking advantage of curbside pickup or home delivery is another way to lessen your contact with germs found in a grocery store.

Most Common Methods of Grocery Shopping

Did the sharp rise in availability of other methods of grocery shopping – like curbside pickup and home delivery – affect how Americans shop? To study that, we asked more than 1,100 Americans how they shop for food regularly. According to our results, the top five most common methods of grocery shopping are:

  1. Shopping inside stores
  2. Home delivery
  3. Curbside pickup
  4. Outdoor markets
  5. Friend or family delivery

Although the popularity of home delivery and curbside pickup rose at the height of the pandemic, these newer methods have not yet been able to unseat the champ – old-fashioned in-store shopping. Sixty-one percent of Americans ranked in-store shopping as their most commonly used method for getting groceries, while second-place home delivery only captured 17% of shoppers. Our survey also revealed that men were slightly more likely to shop inside a store than women. Women used home delivery services and curbside pickup options more frequently than men.

Despite the recent growth of online grocery shopping, its failure to capture a majority of Americans suggests there are still barriers to this method for many people. Maybe some can’t or don’t want to pay the extra fees for delivery services. Perhaps there’s a technology disconnect for others. People could also prefer to choose their own items or may have had a negative experience with these services. Whatever the case may be, the grocery industry is evolving, and some changes may be here to stay.

American Grocery Shopping Habits

The pandemic has changed how we shop for food in many ways. In response to safety precautions and restrictions, Americans have taken advantage of technology to create new grocery shopping habits over the past years. And fortunately, it seems that many of these advancements are here to stay for people who want to proactively protect themselves from different types of viruses, germs, and bacteria.

The large push for contactless shopping during the lockdowns has led many stores to adopt new services or improve upon existing ones, which a lot of shoppers have turned to as a way to stay safer. According to our research, more than 70% of Americans shopped for groceries online in the past three months, even though it’s not their most common shopping method. Of those who currently shop for groceries online, 45% did so for the first time during the pandemic.

Many Americans now know how to shop for groceries online with either home delivery or curbside pickup, and grocery stores are better equipped than ever to offer these services. Our study revealed that nearly 90% of shoppers who tried online grocery shopping for the first time during the past year planned to make online shopping a part of their normal lives.

Reasons for keeping these new shopping habits may be related to time, budget, and health benefits. Germs in grocery stores have always been there – even well before the pandemic – and with alternatives to in-store shopping now available, continuing contactless shopping habits makes sense for those who wish to limit their exposure to germs, viruses, and bacteria of all kinds.


Grocery stores are the dirtiest by the end of the day and on the weekend when they’re crowded. The cleanest and best time to shop for groceries is early in the morning on a weekday. If you like to shop in the store but are worried about germ exposure, take some simple sanitary precautions like hand-washing, sanitizing wipes, and face masks to help keep illness at bay.

Our Data

Survey data were gathered from 1,183 American adults ranging in age from 18 to 78 with a median age of 37. 654 were millennials, 322 were Generation X, 141 were baby boomers, and the other 66 were from Generation Z or older generations. 599 were men, 573 were women, and 11 were nonbinary or nonconforming. Data for comparison to common household surfaces were retrieved from the 2011 NSF International Household Germ Study.

Bacterial CFU counts were gathered through surface culture gram stain analysis on various swabs of grocery store surfaces. Samples of approximately 10 square inches each were taken at three grocery stores, twice on each surface in the morning hours after opening and twice on each surface in the evening hours before closing. The tests were performed during the COVID-19 lockdowns and all the stores that participated were sustaining “enhanced sanitation procedures.” Some shopping carts in the study were retrieved from return bays in parking lots, while others were retrieved from the distribution spot at the front of the stores. Little difference was found between the two in the surface analysis.

Limitations of this study include the reliance of survey data on self-report, which can lead to a number of issues including recency bias, telescoping, survey bias, and others. Where bacterial analysis is concerned, conditions in grocery stores often vary by location, time, and layout. This research should be considered in conjunction with research from other sources to provide better context for broad patterns that may be observed in stores at large.

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