Food Protection Trends - January/February 2020 - 13

L. monocytogenes

E. coli O157

S. aureus

Salmonella

Presence (%)
Figure 2. Presence of foodborne pathogens on shopping trolleys and handheld baskets.
Data represent the prevalence (%) among all the tested samples (n = 96).

contamination on trolleys and handheld baskets used during
grocery shopping. Existing studies on trolley contamination
have expressed concerns mostly associated with infants'
exposure to pathogens (8, 14, 20); however, it is important to
recognize the high potential for cross-contamination of food
products if trolleys and baskets carry foodborne pathogens.
The bottom surface of handheld baskets carried every
foodborne pathogen tested for (E. coli O157, Salmonella sp.,
L. monocytogenes, and S. aureus), and also had the highest
concentration of indicator microorganisms. The visible
uncleanliness of handheld baskets could potentially harbor
organisms, favor bacterial multiplication, and encourage
biofilm formation. Basket and trolley contamination could
be caused by leaking from pre-packaged foods, condensation
from cold items, or dripping of water from produce that
may contaminate surfaces. Trolleys are often parked outside
the stores, where they are exposed to birds, dust, dirt, and
weather conditions. Raw products such as produce, meats
and seafood are known to carry APC microorganisms, YM,
and potential pathogens as reported by Jeddi et al. (2014),
who found APC levels between 5.3 and 8.5 log CFU/g; yeast
and molds in 100% of their surveyed samples, including
minimally processed vegetables and bagged sprouts, and
generic E. coli (13). Other authors have reported similar
findings. Zhao et al. (2001) found Campylobacter spp., E. coli,
and Salmonella in chicken, turkey, pork, and beef obtained
from retail stores (28). Samadpour et al. (1994) investigated
the occurrence of Shiga toxin-producing E. coli in fresh
seafood and meats from grocery stores and found a 17%
prevalence of virulent species in 294 samples (23). These

examples provide evidence that pathogenic microorganisms
can occur on raw foods in supermarket settings, and these
may possibly be transferred to trolley and cart surfaces if
food packaging is compromised. As mentioned, consumers
may place food such as un-bagged produce into direct
contact with the bottom of a trolley or handheld basket,
making grocery trolleys and baskets potential sources of
contamination with foodborne pathogens. Therefore, the
risk of foodborne illness attributable to the lack of cleanliness
of trolleys and handheld baskets must be considered.
With regard to trolley handles, this study found high
bacterial loads of the indicator microorganisms studied
(APC, EB, CF, and EC). These high levels could be
attributed to cross-contamination with customers' hands, as
contaminants can be transferred from hands to trolley and
basket surfaces and vice versa (2, 5). It is widely known that
hand hygiene plays an important role in food contamination.
Proper hygiene and hand washing habits should be practiced
during grocery shopping, not only to prevent contamination
of hands, but also to avoid becoming a vehicle for transferring
microorganisms to other surfaces. As observed during sample
collection, different grocery stores appeared to have different
cleaning and sanitation standards. Some had greater visible
filth and had surrounding areas that required cleaning, while
other stores were maintained in much better hygienic and
aesthetic condition. These differences were consistent with
the numbers obtained for the indicator microorganisms,
and explain the large standard deviations observed in the
results. Strategies implemented by stores are much needed
and include educational and informative communication

January/February Food Protection Trends

13
Food Protection Trends - January/February 2020

Table of Contents for the Digital Edition of Food Protection Trends - January/February 2020
