Food Protection Trends - January/February 2020 - 14

to customers, encouraging them to wipe trolley and baskets
handles and use produce bags and recommending the use
of protective blankets on which to place their infants in
shopping carts, among other recommendations.
Trolley grills consistently had lower levels of bacterial
concentration, perhaps because of the design and smaller
amount of material constituting the surface area. Grills are
made of metal wires that do not fully cover the area, so the
covered surface area per cm2 is much lower than estimated.
Trolleys are used when larger amounts of groceries will be
purchased, perhaps increasing the chance of using bags to
wrap food items. Nonetheless, E. coli O157, Salmonella spp.,
and S. aureus were found on trolley cart grills, which indicates
a possible risk to public health.
This study presents evidence of food safety risks to public
health associated with grocery shopping, which is consistent with findings of other publications (9, 19). In general,
grocery stores lacked sanitation protocols to properly clean
and maintain carts and baskets, a lack that may enhance
bacterial pathogen risk, increase the microbial load on these
surfaces, and possibly increase biofilm formation (16, 24).
Since trolley contamination is emerging as a public health
concern, patents now exist to allow for the implementation
of washing machines or covers for the trolleys to mitigate
these risks (4, 17).
It is recommended that supermarkets implement sanitation
operating procedures to baskets and trolleys to help reduce
risk. Some retail establishments already have implemented
measures by providing sanitizing wipes, and even some
states recommend this measure, as is the case of Arkansas
through their Health-conscious Shopper Act (25). To protect
public health, food processing facilities, as well as grocery
stores, should implement proper sanitation protocols. There
also appears to be a need to create consumer awareness and
education with regard to hand hygiene and use of produce
bags to protect unpackaged produce. It will also be important
to enforce proper trolley and handheld basket sanitation
regulations along with performing microbial surveillance.
Since trolleys and handheld baskets are not considered
food contact surfaces under sanitation programs and
hygiene practice regulations, little attention is given to this
matter. Consequently, risk factor studies associated with
retail store environments are scarce. A 2010 risk assessment

(27) conducted by the U.S. Food and Drug Administration
(FDA), which collected information from 1998 to 2008,
evaluated sanitation conditions in various establishments,
including retail stores, over a period of 10 years. Although
improvements were observed over time, some of their
findings show the need for enhancement of hygiene practices
and cleanliness of food contact surfaces at the meat, poultry,
and seafood departments. Even though there was a focus
on food handling behaviors and hygiene practices, study of
trolleys and handheld baskets was excluded, and microbial
data were not part of the assessment.
CONCLUSIONS
Findings from this study demonstrate the presence of
microbial contamination and foodborne pathogens on
trolleys and the bottom surface of handheld baskets. This may
suggest a public health risk associated with grocery shopping
if food comes into direct contact with these surfaces. The
fact that all the foodborne pathogens tested for were found
on the surveyed samples should be evidence that public
health authorities and private retail stores need to address
the situation and take focused measures to mitigate this
problem. The high microbial load of Enterobacteriaceae and
Coliforms (concentrations up to 6 log CFU/cm2) also need
to be further examined. Fruits and vegetables are often placed
on trolleys and in handheld baskets without protection;
similarly, meat and other foodstuffs may be wrapped in
packaging that is not properly sealed at the meat counter or
juices from pre-packaged meats may drip and contaminate
surfaces. While this study does not correlate its results to
foodborne illnesses, the threat must be acknowledged. As
food contact surfaces are controlled at retail stores, trolleys
and baskets should be included in their standard and
mandatory sanitation programs. Retail stores could also
encourage customers to use sanitizing wipes to clean their
hands and handles prior to and during shopping to use bags
to wrap fruits, vegetables, and especially meat and poultry to
provide an additional barrier of protection.
ACKNOWLEDGMENTS
The authors acknowledge Dr. Jon Thompson, Ana Portillo,
and Keelyn Hanlon for their contributions to this project and
for their help in collecting samples.

REFERENCES
1. Banatvala, N., A. Magnano, M. Trolleyter,
T. Barrett, W. Bibb, L. Vasile, P. Mshar,
M. Lambert-Fair, J. Green, N. Bean, and
R. Tauxe. 1996. Meat grinders and molecular
epidemiology: Two supermarket outbreaks
of Escherichia coli O157:H7 infection. J. Infect.
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2. Barker. J., I. Vipond, and S. Bloomfield.
2004. Effects of cleaning and disinfection
in reducing the spread of Norovirus
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3. Beuchat, L. 1998. Surface decontamination
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4. Boucher, J., and P. Mitchell. 1989. Handler
cover and seat cover for a shopping cart.
U.S. Patent 07/168,923.
5. Brouwer, D. 1999. Transfer of contaminants
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assessment of linearity of the exposure
process, adherence to the skin, and area
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Food Protection Trends January/February

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6. Center for Science in the Public Interest. 2015.
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