3.2. Mould and yeast
Overall, moulds are present in counts greater than
1 log CFU cm2 in 86 samples (14.6%) of which 25 and 61 in wall and
bottom samples respectively. There are 16 samples with a fungal
count 2.5 log CFU cm2
, of which 12 are from bottom shelves and
4 from walls (Fig. 2). Similarly, yeasts also prevail on the bottom of
the refrigerator and there are 28 samples with counts
2.5 log CFU cm2 of which 22 are from bottom shelves. The highest value found for moulds was 3.5 log CFU cm2 from the
bottom shelf.
Only phenotypic identification of the moulds allowed us to
hypothesize the presence of the genera Penicillium and Aspergillus,
the latter mainly on the bottom of the fridge.
3.3. Pseudomonas spp. and Aeromonas spp.
Pseudomonas spp. are substantially present (>10 CFU cm2
) in
77 samples (63 bottom shelves and 14 walls) with a percentage of
13% out of the total area analyzed and 21.5% and 5% for the bottom
and the wall respectively. In 8 refrigerators they are present in both
the sampled parts. Considering the counts 2.5 log CFU cm2
, the
number of samples decreases to 28 (23 in the bottom and 5 in the
walls) (Fig. 3). The highest value found was 3.4 log CFU cm2 in a
sample from the bottom of a refrigerator.
Aeromonas spp. present counts greater than 10 CFU cm2 in 26
samples (23 for the bottom shelves and 3 for the walls), with a
prevalence of 4.4% out of the total of samples and in only 2 refrigerators
are present in both parts. The highest value was on the
bottom (3.8 log CFU cm2
).
At the next identification of species, carried out first by viewing
fluorescence under a Wood’s lamp then with an oxidase test and a
biochemical test, we obtained 16 Pseudomonas fluorescens, 6 Pseudomonas
putida, 1 each of Pseudomonas cepacia and Pseudomonas
pseudomallei. Almost all of the identified strains were isolated from
samples taken from the bottom, of which 8 had a count
2.5 log CFU cm2
. The prevalence of Ps. fluorescens out of the total
number of samples analyzed is 2.8%. Considering only the samples
taken from the bottom of the refrigerator, the percentage rises to
5.2%.
3.4. B. cereus and coagulase-positive staphylococci (CPS)
A search for B. cereus and CPS was carried out on 162 refrigerators,
for a total of 324 samples. B. cereus was identified in 18
samples of which 15 from the bottom of the refrigerator, with a
maximum count valued at 2.1 log CFU cm2 (2 samples). The
pathogen is therefore present in 5.6% of the samples analyzed.
CPS are present in 13 samples of which 10 from the bottom.
Maximum microbial count is 2.0 log CFU cm2 (2 samples). The
pathogen is present in 4% of the samples analyzed. Research was
not carried out for staphylococcal enterotoxins, since their counts
were found to be very low.
3.5. Other pathogens
Salmonella spp. was found in 8 samples, 5 of which were from
the bottom. Note that in 7 samples the TVCs were
2.5 log CFU cm2
. Its prevalence is 1.4% overall, and 1.7% if we
consider only the samples from the bottom. In one sample, whose
average TVC was 2.8 log CFU cm2
, represented mainly by Pseudomonas
spp. and yeasts, the pathogen was found both on the
bottom and on the wall.
3.2. Mould and yeastOverall, moulds are present in counts greater than1 log CFU cm2 in 86 samples (14.6%) of which 25 and 61 in wall andbottom samples respectively. There are 16 samples with a fungalcount 2.5 log CFU cm2, of which 12 are from bottom shelves and4 from walls (Fig. 2). Similarly, yeasts also prevail on the bottom ofthe refrigerator and there are 28 samples with counts2.5 log CFU cm2 of which 22 are from bottom shelves. The highest value found for moulds was 3.5 log CFU cm2 from thebottom shelf.Only phenotypic identification of the moulds allowed us tohypothesize the presence of the genera Penicillium and Aspergillus,the latter mainly on the bottom of the fridge.3.3. Pseudomonas spp. and Aeromonas spp.Pseudomonas spp. are substantially present (>10 CFU cm2) in77 samples (63 bottom shelves and 14 walls) with a percentage of13% out of the total area analyzed and 21.5% and 5% for the bottomand the wall respectively. In 8 refrigerators they are present in boththe sampled parts. Considering the counts 2.5 log CFU cm2, thenumber of samples decreases to 28 (23 in the bottom and 5 in thewalls) (Fig. 3). The highest value found was 3.4 log CFU cm2 in asample from the bottom of a refrigerator.Aeromonas spp. present counts greater than 10 CFU cm2 in 26samples (23 for the bottom shelves and 3 for the walls), with aprevalence of 4.4% out of the total of samples and in only 2 refrigeratorsare present in both parts. The highest value was on thebottom (3.8 log CFU cm2).At the next identification of species, carried out first by viewingfluorescence under a Wood’s lamp then with an oxidase test and abiochemical test, we obtained 16 Pseudomonas fluorescens, 6 Pseudomonasputida, 1 each of Pseudomonas cepacia and Pseudomonaspseudomallei. Almost all of the identified strains were isolated fromsamples taken from the bottom, of which 8 had a count2.5 log CFU cm2. The prevalence of Ps. fluorescens out of the totalnumber of samples analyzed is 2.8%. Considering only the samplestaken from the bottom of the refrigerator, the percentage rises to5.2%.3.4. B. cereus and coagulase-positive staphylococci (CPS)A search for B. cereus and CPS was carried out on 162 refrigerators,for a total of 324 samples. B. cereus was identified in 18samples of which 15 from the bottom of the refrigerator, with amaximum count valued at 2.1 log CFU cm2 (2 samples). Thepathogen is therefore present in 5.6% of the samples analyzed.CPS are present in 13 samples of which 10 from the bottom.Maximum microbial count is 2.0 log CFU cm2 (2 samples). Thepathogen is present in 4% of the samples analyzed. Research wasnot carried out for staphylococcal enterotoxins, since their countswere found to be very low.3.5. Other pathogensSalmonella spp. was found in 8 samples, 5 of which were fromthe bottom. Note that in 7 samples the TVCs were2.5 log CFU cm2. Its prevalence is 1.4% overall, and 1.7% if weconsider only the samples from the bottom. In one sample, whoseaverage TVC was 2.8 log CFU cm2, represented mainly by Pseudomonasspp. and yeasts, the pathogen was found both on thebottom and on the wall.
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