(1) The premises of 50 manufacturers of ice-cream were inspected, their methods investigated, and bacteriological examinations made of samples taken
“a” immediately after heating,
“b” after cooling,
“c” after freezing.
(2) The trade is not carried on under the conditions or with the precautions necessary to secure a clean product.
The sources of the contamination of ice-cream.
(3) Bacteriologically polluted ice-cream is due to
(A) Insufficient initial heating;
(B) Contamination during cooling and freezing from
(a) unclean vessels and covers,
(b) the addition of unclean ice to hasten freezing,
(c) the unclean hands of the manufacturer,
(d) dirty surroundings.
The scientific method of the manufacture of ice-cream.
(4) To secure a pure ice-cream:
(a) All vessels should be thoroughly cleansed immediately before use and reserved for the manufacture of ice-cream. They should be stored in a clean place.
(b) The manufacturer's hands and forearms should be thoroughly scrubbed and cleansed before each stage of the process. The clothing likely to come in contact with the ice-cream should also be clean.
(c) Fresh milk should be used in its manufacture.
(d) The ingredients should be boiled directly over a fire for ten minutes, or heated by means of a water-bath at boiling point for 30 minutes. The latter method is the better as the former is liable to burn the mixture.
(e) The mixture should be frozen, immediately after boiling preferably in a freezer of the American pattern. Thereafter the ice-cream should be kept frozen while in the vendor's possession.
(f) No ice-cream should be exposed for sale 48 hours after boiling.
(g) The premises on which ice-cream is manufactured should be approved and registered by the local authority and should be constantly supervised.