Home Issue 2017-11-3 New Study Shows Surprising Levels Of Contaminants At Grocery, Upscale Fares Better...

New Study Shows Surprising Levels Of Contaminants At Grocery, Upscale Fares Better Than Budget; Produce Picks Up ‘Riders’


We’ve all seen the (welcome) addition of antibacterial wipes in many grocery stores near the area where you pick up your cart. Turns out we need those more than we thought. A new study shows surprising levels of contamination throughout the store at all retail outlets — budget, traditional, big box and upscale — leading to bacterial levels far higher than those found on say, a pet toy, or even a toilet handle. Worse, that bacteria can easily spread to food, especially fresh produce.

In Italy — No toucha da produce!

What to do about it? Keep using those wipes for starters. And here’s where we may want to take a cue from Europe — in Italy last winter we got chewed out in a foreign language (didn’t understand the words but the message was clear) for picking up produce with our bare hands… when boxes of disposable plastic gloves like those you see in fast food restaurants were dispersed every few feet along the counter.

Meanwhile, check out these surprising — and in some cases disgusting — results from this new study commissioned by the grassroots organization Reusethisbag.com and conducted by EMLab P&K. You can flip through several pages of the infographic below. And keep scrolling for up-close looks at how produce fared under the microscope.

The study based all values on an average of five carts from each store type, as well as three produce items and three refrigerator door handles from each store.

Traditional grocery stores, by far, had the highest bacteria count. Grocery carts at regular and budget stores carry hundreds of times more colony-forming units per square inch (or CFU/sq. in.) than surfaces in your bathroom.

Results show that a cart at a traditional grocery store has over 73,000 CFU/sq. in. – 361 times more CFU/sq. in. than a bathroom doorknob. More so, a shopping cart at a budget store has 270 times more CFU/sq. in. than your average toilet handle.

Superstores follow with over 1,000 CFU/sq. in., which is nearly triple the bacteria on an average kitchen countertop. However, carts at upscale markets had impressive results, with just 28 CFU/sq. in. – about the same as a computer keyboard.

Of all the bacteria present on shopping cart handles, nearly 75 percent were identified as gram-negative rods. Over 90 percent of gram-negative rods can be harmful to humans, and to make it worse, most types are resistant to antibiotics.

Another 24 percent of surface bacteria were identified as gram-positive rods. Although most forms of these bacteria are harmless, they can lead to other illnesses.

Fewer than 1 percent of the samples’ surface germs showed signs of yeast and bacillus. Despite the trace amount, bacillus is commonly linked to food poisoning, while yeast can lead to a skin infection. Another percentage of the test sample included gram-positive cocci. Much like yeast, gram-positive cocci are associated with skin infections, in addition to pneumonia and blood poisoning.

So just how dirty are grocery stores compared to everyday items? Perhaps more than you think.

Refrigerator doors at a traditional grocery store had nearly 327,000 CFU/sq. in. Imagine all the people reaching for these door handles, passing the germs that might already be on their hands over to the door and onto the next person. For comparison, the average pet toy had 18,940 CFU/sq. in. Even the bottom of a handbag had less than 10 CFU/sq. in. of dirty microbes.

Produce sold in upscale grocery stores had more than 1,500 times as many germs than produce found at traditional grocery stores. Produce at upscale supermarkets may be more likely to carry traces of bacteria than conventional foods because of the lack of chemicals and other less effective natural methods farmers take to keep these foods clean. The contamination may also come elsewhere in the supply chain.

According to the research, over 58 percent of the germs covering grocery store refrigerator doors were identified as gram-positive rods. While some research has linked gram-positive bacteria to health treatments, they can sometimes be pathogenic, leading to negative side effects and harmful diseases.

More than a third of the bacteria on grocery store refrigerator doors were identified as gram-positive cocci – which can lead to negative effects in humans – while nearly 4 percent was yeast, and almost 2 percent was infectious gram-negative rods.

Produce tested at various grocery stores was more likely to be covered in harmful bacteria than the refrigerator doors in their vicinity. Less than half of produce bacteria were identified as gram-positive rods, while nearly 19 percent were gram-negative rods.

Of the four stores examined, budget grocery stores had the highest amounts of the least harmful bacteria. More than 96 percent of the germs assessed on these refrigerator doors were identified as gram-positive rods. However, traditional, upscale, and superstores weren’t nearly so clean. Of the bacteria on the refrigerator doors at traditional grocery stores, less than two-thirds were also gram-positive rods. Upscale markets and superstores were where things got officially dirty, however. All germs identified on the refrigerator doors at these two markets were gram-positive cocci. Like gram-negative rods, gram-positive cocci can carry parasites and pathogens harmful to humans. In fact, gram-positive cocci are responsible for a third of all bacterial infections that impact humans.


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