Listeria monocytogenes in Ready-to-Eat Seafood and Potential Hazards for the Consumers
Table 3
Detailed description of microbial charges, aw and pH values of each L. monocytogenes-positive sample (microbiological and PCR tests). Values expressed in CFU/g.
Sample n.
Types of product
Temperature of storage
Mesophiles count
Psicrophiles count
Psicrophiles H2S count
Moulds count
Yeasts count
Lactic count
aw
pH
1
Seafood salad
T0(*)
9 × 108
6.6 × 105
<1
<1 × 102
<1 × 102
2.4 × 108
0.0680556
5:01
T0
2.8 × 104
1.4 × 104
6
4 × 102
9 × 102
9.1 × 102
0.0666667
6:01
2
Salmon carpaccio
4°C(**)
6.5 × 105
3.8 × 105
3.5 × 102
2 × 102
2.4 × 103
6.4 × 105
0.0673611
6:01
10 °C(***)(****)
1.9 × 10 8
1.3 × 10 8
4.7 × 10 4
9 × 10 2
1.7 × 10 4
1.5 × 10 8
0.0673611
6:01
3
Marinated seafood cocktail
4 °C
7.5 × 104
4.5 × 104
<1
< 1 × 102
<1 × 102
3.7 × 104
0.0673611
5:01
4
Octopus carpaccio
10°C
5.5 × 107
3 × 106
<1
<1 × 102
<1 × 102
4.6 × 107
0.0680556
4:09
5
Cooked and marinated Mackerel Fillets(*****)
4°C
4.2 × 106
2.4 × 104
<1
< 1 × 102
<1 × 102
7.3 × 106
0.0680556
5:03
6
Smoked salmon
T0
7.8 × 104
7.4 × 103
<1
<1 × 102
7 × 102
3.6 × 102
0.0638889
6:01
10°C
7.1 × 107
6.1 × 107
1.1 × 107
<1 × 102
1.5 × 105
4.4 × 102
0.0652778
6:03
4°C
1.6 × 105
9.6 × 104
6.9 × 103
4.9 × 103
<1 × 102
2 × 103
0.0673611
6:01
7
Fresh salmon in protective atmosphere
10°C
1.2 × 106
2.2 × 106
8 × 104
6 × 102
5.9 × 103
6.1 × 103
0.0680556
6:00
T0
2.7 × 106
2.2 × 106
2 × 105
<1 × 102
3.6 × 103
9.8 × 103
0.0673611
6:00
8
Smoked salmon
T0
7.6 × 107
4 × 107
1.8 × 105
<1 × 102
3 × 102
2.8 × 107
0.0673611
5:08
4°C
4.2 × 10 8
1.5 × 10 8
1.2 × 10 7
<1 × 10 2
4.5 × 10 4
7.3 × 10 7
0.0673611
6:02
9
Fresh salmon in protective atmosphere
10°C
3.6 × 106
2.9 × 106
5.2 × 103
<1 × 102
3.9 × 103
5.1 × 103
0.0673611
6:02
4°C
6.7 × 106
1.7 × 105
1.4 × 103
<1 × 102
3 × 102
4.1 × 106
0.0673611
6:02
10
Smoked salmon
10°C
1.4 × 10 7
1.4 × 10 7
<1
<1 × 10 2
<1 × 10 2
4.3 × 10 6
0.0666667
6:02
11
Salmon carpaccio
T0
7.5 × 106
3.2 × 106
1.3 × 105
1 × 103
3.5 × 103
1.7 × 105
0.0673611
6:00
12
Cooked and marinated mackerel fillets (*****)
10°C
4.1 × 107
1.2 × 105
<1
<1 × 102
<1 × 102
2.7 × 108
0.0680556
5:03
Note. The lines with bold lettering refer to the 3 samples with a L. monocytogenes concentration of >100 cfu/g.
(*): zero time, analysis of one of the three sample units on the day they reached the laboratory.
(**): 4°C, analysis at the end of shelf-life at 4°C storage conditions.
(***): 10 °C, analysis at the end of shelf-life at 10°C storage conditions in the last third before final expiration.
(****): packaging with bulging at the end of shelf- life with no unpleasant odour.
(*****): samples from the same company but from different batches.
