EFFECT ON QUALITY

Bay of Plenty Beacon, Volume 2, Issue 153, 29 April 1940, Page 2

EFFECT ON QUALITY

PASPALUM FUNGUS IN RELATION j TO CREAM (Written for the BEACON by Mr F. S. Hodson, bacteriologist to the Rangilaiki Plains Dairy Co., Ltd.) In investigating recent cream troubles it was necessary to exclude mastitis as a possible cause. To do this, microscopical examinations of the risen cream of mill? samples from individual cows were made. Many of these smears showed conidia or spores identical with those found in the sticky material on paspalum .ssed heads. Sterile and raw milks and creams were inoculated with the sticky material and although undesirable flavours, increased acidity, fermentation, accelerated reduction of methy 'ene blue could be produced, the paspalum conidia apparently did not undergo any further stage of active development and so presumably were, not the organisms responsible, Cultures showed yeasts and moulds and some milks on further incubation developed alcoholic odours. The presence of the yeasts and moulds is explainable as follows: on the paspalum seed head the fungus "claviceps paspali" attacks the ovary rvf the young flowers, grow r s upon them and produce enormous numbers of conidia or spores embedded in a sticky slime which is attractive to insects. This is easily dissolved by rain and the conidia thus carried to other blossoms. Yeasts and moulds are also deposited on this stick material either from the air or by ifir sects such as "stable" flies. In paspalum country, the cows' udders become well coated with the slime and this can easily be transmitted into the milk from excess water used in washing the cows' udders and teats; dripping into the cups or from the milkers hands. It is significant that at one factory luring the paspalum season some of the hand milked herds have had the most trouble with grade. It seems definite that the paspalum fungup itself is not responsible but the yeasts, moulds and bacteria collect-) ed on the sticky material. Many other factors can then decide the variation in flavours, fermentation or curdling observed. Owing to contamination by bacteria from a bad water supply or from shed conditions, preliminary acidity may be produced in milk or cream and this acidity would favour the rapid growth of certain yeasts in warm weather. Other species flourish under cooler conditions. Thus it is possible to understand the various flavours and results met! with and why they are not consistent on the same or different farms. Cows having a preference for eating the sticky seed heads may develop so called "paspalum staggers" Up to the present the paspalum fungus has been held responsible for this condition but it is possible that yeasts and bacteria trapped in the sticky material may be the agents responsible for the condition. The milk and cream changes occur from external contamination and not through the system of the animal. The remedy for avoidance of both "paspalum staggers" and some grading troubles prevalent during the paspalum seeding period is in pre-> venting the paspalum from seeding, keeping it topped or not allowing cows access to seeding pastures. Where this is impossible, the greatest care in washing udders and avoiding contamination from the milkers' hands is essential.