Bacteriologist Dr James Bruce was giving evidence on day three of the
Lanark Blue cheese hearing at the town's sheriff court.
He said soft cheeses had been associated with listeriosis in humans
but the different varieties of semi-hard blue vein cheeses had not.
His research had discovered a report that stated two out of 20 samples
of different blue cheeses in the Netherlands were found to be
contaminated with the organism.
Dr Bruce, 55, is head of the food microbiology unit at the Scottish
Agricultural College, Auchincruive, Ayrshire, where 50 samples of Lanark
Blue were tested.
Referring to a background report given in evidence to the court, he
explained why he had included foreign reports of listeria monocytogenes.
Dr Bruce said: ''You can't give blue cheese a completely clean bill of
''The fact that the organism is there leads us to this possibility
that there could be an outbreak of illness.''
Dr Bruce said all 50 samples of Lanark Blue treated at his unit were
contaminated with the organism. He said it was his academic opinion that
the Lanark Blue was not safe to eat.
There was no merit, he said, in the argument that the type of bacteria
discovered was harmless.
Dr Bruce admitted he had no detailed knowledge of how Lanark Blue was
produced from unpasteurised ewes' milk by Humphrey Errington at his farm
The allegedly contaminated cheese, worth #27,000, has been deep frozen
at Mr Errington's farm since February.
Clydesdale District Council is seeking an order from the court to
destroy the frozen cheese because it believes it is unfit for human
Cross-examined by Michael Jones QC, representing Mr Errington, Dr
Bruce agreed that not all strains of the bacteria caused illness.
The hearing continues.