Levels of microbial contamination of domestic refrigerators in Italy

- Hygiene in food storage in the kitchen is not always properly implemented.
- We examine the inner surfaces of 293 domestic refrigerators in Veneto (Italy).
- The main microbial count is mostly present on the bottom of the refrigerator.
- In 50% of the refrigerators the TVCs are unacceptable according to Dir. 2001/471/EC.
- Salmonella spp. was found in 8 samples (1.4%); Ps. fluorescens and fungi are prevalent.

AimAccording 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 methodsWe 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.ResultsTVCs greater than 1 log CFU cm−2 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.ConclusionsIt is necessary to better educate consumers to clean their appliances more frequently.