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Domestic
Kitchen Refrigerator: A Potential Reservoir for Pathogenic Bacteria
Agnes
Kilonzo-Nthenge, Fur-Chi Chen, and Sandria L. Godwin
Institute of
Agricultural and Environmental Research
Seminar Series
Tennessee State University, Nashville, TN
March 8, 2006
A significant
proportion of foodborne illnesses are due to cross-contamination in the
domestic kitchen environment. Pathogens have been identified at a wide
array of kitchen sites including dishcloths, sponges, oven door handles,
counter-tops and draining boards. While possible cross-contamination
through most of these avenues has been researched, there is paucity of
information on potential pathogens in the domestic refrigerator. The
goal of this study was to evaluate the prevalence and levels of
pathogenic Enterobacteriacea and aerobic bacteria in domestic
refrigerators. Meat and vegetable bins as well as the top shelf of each
refrigerator were swabbed to collect samples. Butterfields Phosphate
Buffer was added (1:10) to the samples which were homogenized, and then
serially diluted (0, 10-1, 10-2, and 10-3)
for subsequent plating onto 3M Petri film Enterobacteriacea and
plate count agar (PCA). The 3M Petri film Enterobacteriacea and
PCA plates were incubated at 36o C for 24 hr and 35o
C for 48 hr, respectively. Api20E was used for identification of
Enterobactericea. The populations for Enterobacteriacea
and aerobic plate counts ranged from 0.6 – 6.95 log CFU/100 cm2
and 1.04 – 7.13 log CFU/100 cm2,
respectively. Klebsiella pneumoniae spp pneumoniae (25.5 %),
Klebsiella oxytoca (8.2%), Yersia enterocolitica (1%), and
Enterobacter Sakazaki (2 %) were among the most prevalent pathogenic
bacteria isolated from the domestic refrigerators. The high populations
for Enterobacteriacae and aerobic bacteria in refrigerators
suggested poor sanitation. The results indicate that kitchen
refrigerators can be potential reservoirs for pathogenic bacteria;
therefore, present a hazard for contaminating prepared foods and other
parts of the domestic kitchen.
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