An improved selective isolation medium for the recovery of Listeria monocytogenes from smoked fish.
OBJECTIVE
The aim of this study was to improve the selective isolation of Listeria monocytogenes from smoked haddock fillets.


RESULTS
Listeria selective agar (LSA)--Oxford formulation was supplemented with 25 microg x ml(-1) of colistin sulphate and 30 microg x ml(-1) of nalidixic acid. Inocula from four smoked haddock fillets produced colonies (approx. 2-13 bacteria x g(-1)), identified as L. monocytogenes, on LSA supplemented with antimicrobial compounds (MLSA). Moreover, there was only negligible evidence of bacteria which were not L. monocytogenes on MLSA. In contrast, LSA supported dense bacterial growth, which was not equated with L. monocytogenes.


CONCLUSIONS
The modified medium permitted the recovery of L. monocytogenes from smoked haddock fillets and reduced the growth of contaminating bacteria.
Neamatallah
A A N
AA
School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh, UK.
Dewar
S J
SJ
Austin
B
B
D000818:Animals; D001431:Bacteriological Techniques; D015169:Colony Count, Microbial; D003470:Culture Media; D005399:Fishes / Q000382:microbiology*; D005516:Food Microbiology; D005524:Food Technology / Q000379:methods; D006801:Humans; D008089:Listeria monocytogenes / Q000302:isolation & purification* / Q000472:pathogenicity; D008088:Listeriosis / Q000209:etiology
D003470:Culture Media