From each processing line, 25–32 isolates were selected per
sampling-day originating from the fillets samples at the beginning
(filleting), middle (trimming) and final (freezing) processing steps
taking into account as many different colony morphologies (e.g. color,
size, and shape) as possible on the media used. A total of 252 isolates
were purified and stored on Tryptone Soy Agar (TSAMerck, Darmstadt,
Germany) slants at 4 °C.