CHEESE MAKING PROBLEM

Press, Volume LXXI, Issue 21512, 29 June 1935, Page 14

CHEESE MAKING PROBLEM

♦ STARTER CULTURES

DESTRUCTIVE GERM DISCOVERY BY RESEARCH INSTITUTE (I'ItESS ASSOCIATION TELEGRAM.) PALMERSTON N., June 28. A remarkable discovery has been made by research workers at the dairy research institute. It is the presence in cheese starters of a germ which produces such a powerful inhibitory substance that it practically prevents the growth of another. Speaking to the National Dairy Association Conference to-day, Professor Riddet, director of the institute, declared that it was the first case on record of such a thing happening 'in cheese starter cultures, though it had been known in medicine for man,) years. "The discovery was mad Q in February of this year by Dr. Whitehead, when endeavouring to discover why pure strains of cheese starter died suddenly from an unknown cause," Said Professor Riddet. "At first this seemed an insuperable barrier, but chance observation maue in the course of conducting a test revealed the astounding fact that cultures apparently pure bacteriologically may be infected with a kind of virus known as bacteriophage. This bacteriophage is some vha' similar to Ihe viruses which affect plants and animals; for example, mosaic disease of the potato plant, and foot-and-mouth disease of cattle, are both due to virus infections. The causal factor cannot be observed under the microscope, and it passes through the finest filters which are used in laboratories for separating bacteria from the liquid in which they are suspended. Rapid Destruction "This bacteriophage is a remarkable thing. It has the unique properly, when present in infinitely prnall amounts (e.g., one part in severai millions) of suddenly destroying starter organisms, and it works with enormous rapidity. Within an hour it may completely destroy a starter which previously ;,as been normal. This may happen in a cheese vat. The starter may grow normally during the first hour or two of the manufacturing process, and then be destroyed by bacteriophage, thus rendering it practically impossible to produce cheese ol the best quality. Remedy a Matter of Time "This bacteriophage condition has been known in medicine for many years, but it is the first time on record that its presence has been revealed in any part of the world in starter cultures. It is not known where bacteriophage starters originate, and, as can oe realised, this is extremely difficult tc determine. Nevertheless, no 7 th_t its presence is known and itr action recognised, ihere is something definite to look for and the finding of the means to nrevent its iction is only a matter of time. At the m ,ment there is not yet an adequate solution of the problem ot overcoming it in starters, or nf avoiding it, but there is some hope alor.g the l:.:es of getting strains immune to it. Indeed, already some strains have been worked up which are definitely less rensitive than others. It is abundantly clear that th'*- fundamental work on starter: has provided an invahiable clue to a real understanding of how starters lose their vitality when given every care." Later in the conference Professor Riidet said the Institute for a long while had been looking for this "needle in a haystack" of cheesemaking difficulties, and now that it had been discoverea it would not be I long before starter troubles would be overcome.