Aim: According to the EFSA Report 2013, 32.7% of outbreaks of foodborne illness registered in Europe
occurs within the home, due to inadequate hygienic behaviour of consumers when preparing foods in
the kitchen. The efficacy of proper cleaning of cutting boards, dishes and cutlery in limiting microbial
cross-contaminations in the kitchen has been documented many times, whereas few researches have
been performed to determine the microbial load of the internal walls of domestic refrigerators, in Italy.
The aim of this investigation is to ascertain the role played by internal surfaces of home refrigerators as
possible sources of microbial contamination of foods.
Material and methods: We analyzed 293 domestic refrigerators of students or workers at the university
campus of Agripolis (Legnaro, Italy). For each refrigerator, 2 internal surfaces were sampled using
sponge-bags. The amounts of total viable count (TVC), Gram-negative spoiling bacteria, moulds and
yeasts and the main pathogenic bacterial species were determined.
Results: TVCs greater than 1 log CFU cm2 are in a little over 50% of the samples analyzed and are found
mainly on the bottom of the refrigerator (61%) compared to the walls (39%) (P < 0.001). Even for other
microbial counts the risk ratio of finding them on the bottom of the refrigerator is significantly higher
than on the walls; the possibility of there being a finding on the bottom with respect to the walls varies
from 2.5 to 8.5 times respectively for moulds and Aeromonas spp. Salmonella spp. was found in 1.7% of the
samples, Bacillus cereus in 5.6%, Coagulase-positive staphylococci (CPS) in 4%, the prevalence of which is
always higher on the bottom of the refrigerator. Listeria monocytogenes and Yersinia enterocolitica were
never found.
Conclusions: It is necessary to better educate consumers to clean their appliances more frequently