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21
Dairy X thus became noticeable, though scarcely suspicious, towards the
end of May, as being associated with cases of scarlet fever, the numbers thus
occurring in households served by the dairy increasing somewhat at the end
of the month and early in June. There was no material increase in cases
of scarlet fever deriving their milk from other dairies in Croydon, and it is
perhaps worth noting that of the 9 cases with onset in the week ending
June 7th supplied by dairies other than X, two were sisters capable of being
infected by direct contact with cases at school B; while two others were
from another known source of infection distinct from the present outbreak.
The enquiries summarised above were carried out throughout the 9th
June; the fact that this was a Bank Holiday added some complication to
the procedure of obtaining the necessary information. On the 10th the dairy
X was visited; the workers were all examined and were found to be clean
and healthy, with no record of suspicious illness, and they were not further
implicated. The procedure in force at the dairy, and the methods of dealing
with utensils, etc., also called for no comment. The milk received at this
dairy comprised two separate supplies; one consisted of pasteurised milk
from a dairy in Purley; the other, constituting three-quarters of the
whole, was unpasteurised fresh milk, received daily from a farm, in a neighbouring
district. The two sets of milk were mixed at the dairy, and delivered
on a series of rounds. It was ascertained that these rounds corresponded
closely with the area in which cases of tonsilitis were known to have
occurred.
The farm from which the unpasteurised milk came was visited. No
point of note arose in regard to buildings, methods of milking, water supply,
etc. All the milkers, with one exception, were found to be healthy and
without history of suspicious illness. The exception consisted of the head
milker, in regular employment at the farm for many years, who had a septic
condition of the hand, evidently of old standing, showing open sores and
deep cracks in the skin and flesh between the fingers. The fact that a
rag was wrapped round the fingers suggested a recent recrudescence of the
condition, although this was denied by the milker. It was clear that this
milker could readily cause a gross degree of infection of the milk with
organisms squeezed from his unhealthy fingers during the process of milking,
and such organisms would multiply rapidly—for milk is an exceptionally
good medium for their development—during the hours elapsing before the
milk was used. It will be noted that this milk was not pasteurised, either
at the farm or at dairy X, and that in the cases investigated it was not
boiled in the home.
The position was discussed with the firm of dairymen concerned, and
with the greatest promptitude they transferred this milker to work not connected
with milking, and subsequently, so I was informed, to work not
associated in any way with the milk trade. Owing to the pressure of work
at the time, the opportunity was not taken of attempting to obtain cultures
of organisms from the man's hand.
The firm were advised to arrange for the pasteurising of the whole of
the milk sent out from this farm. This was put into effect immediately,
and by the next day (the 11th June) the whole of the milk was being
pasteurised at a milk depÔt provided with the necessary plant, whence it was
conveyed to dairy X for distribution.
Through the courtesy of the Medical Officer of Health of the
district concerned, with whom there was the closest collaboration
throughout the whole investigation, a veterinary inspection was made
of the cows at the farm. All the cows were healthy except one, certified
as having " cowpox," and a second showing a grazed and bruised leg. The
milk from these cows was examined bacteriologically at the Borough Hospital,
but nothing suspicious was found. Both cows were removed from the
milking herd. The cow with cowpox had only been received into the herd a
few days previously, and could not account for the whole of the outbreak.