Table 1.
Flow chart of gravlax salmon processing, sample category, serogroup, number of isolates, PFGE profiles and clusters.
| Flow processing | Sample category Serogroup (n° of isolates) | Combined profiles of Apal and AscI | Clusters | |
|---|---|---|---|---|
Reception
|
raw salmon (S1) | 1(8) | P1C1, P2C1, P2C2, P2C12 | A |
| handlers (H1/H2) | 1(11), 4(1) | P7C14,P7C27,P11C18,P30C18 | A | |
| knife, table (U1/U2/U3) | 1(9) | P20C21,P30C18 | A/C | |
| drain, floor (E1/E2) | 1(10), 4(4) | P20C12,P21C18,P21C19,P21C23, P22C22,P30C18 | A/C | |
1st Curing
|
cured salmon (S2) | 1(1), 4(7) | P2C5,P3C3,P4C4,P4C7,P5C6 | A/B/C |
| handler (H3) | 1(3) | P30C13 | A | |
| table, box (U4/U5) | 1(5), 4(6) | P9C7,P21C12,P22C13 | A/B | |
| curing ingredients (I1) | *- | - | - | |
Salt removal
|
handler (H4) | - | - | - |
| boxes, table (U6/U7/U8) | - | - | - | |
| floor, drain (E3, E4) | 1(12) | P20C24,P21C28,P22C18,P30C28 | A/C | |
Washing
|
washed salmon (S3) | 1(5), 4(3) | P5C6,P7C9,P29C8 | A/B/C |
2nd Curing
|
cured salmon (S4) | 1(4), 4(2) | P1C2,P1C7,P8C2,P8C10 | A |
| handler (H5) | - | - | - | |
| table (U9) | - | - | - | |
| curing ingredients (I2/I3) | - | - | - | |
Jerez spraying
|
cured salmon (S5) | 4(5) | P9C7 | B |
| handler (H6) | 4(3) | P4C26 | B | |
| trolleys (U10) | - | - | - | |
Ripening
|
gravlax with skin (S6) | 1(7), 4(1) | P6C2,P7C14,P10C3,P11C19 | A/C/E |
| floor,door,wall (E5,E6,E7) | - | - | - | |
Skinning
|
gravlax without skin (S7) | 1(6), 4(2) | P5C6,P6C1,P6C8,P11C19,P12C7 | A/B |
| handler (H7) | - | - | - | |
| trolley,table,knife (U11/U12/U13) | 1(6) | P23C1 | A | |
Slicing
|
sliced gravlax (S8) | 1(5), 4(3) | P1C2,P5C11,P11C13,P13C17,P14C16 | A/B/C/F |
| handler (H8) | 1(7) | P11C1,P28C1,P27C1 | A | |
| conveyor belt, blade (U14/U15) | 1(5) | P24C19 | A | |
| floor, drain (E8, E9) | 1(12) | P22C13,P25C13,P26C13 | A | |
Portioning
|
handler (H9) | - | - | |
| tray, scale (U16/U17) | 1(6) | P17C13,P21C19 | A | |
Vacuum-packing
|
package gravlax (S9) | 1(6) | P1C1, P15C27 | A/B |
Cold storage
|
refrigerated gravlax (S10) | 1(3), 4(3) | P2C18,P4C6,P4C20,P16C18,P17C18 | A/B |
| Frozen storage | frozen gravlax (S11) | 1(2), 4(6) | P11C18,P18C15,P19C7 | A/B/D |
*
= no positive samples for L. monocytogenes, _ = serotype 4 strains points.