435. Keeping quality and raw-milk grading: II. The effect of storage on the results of keeping quality and dye tests

Eddison, R. T.; Kempthorne, Oscar; Hosking, Zena D.; Barkworth, H.; Cox, Christopher; Rowlands, A.

doi:10.1017/s002202990000594x

Cited by 16 publications

(5 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Correction of the keeping quality times for the portions held for 23 hr. a t 14" t312 for the equivalent periods of storage was made using the formula R(t)= of milk a t different temperatures (Eddison et al 1951). From this, calculation shows that each hour of storage a t 14"(t) is equivalent to 0.46 hr.…”

Section: Experimental Methodsmentioning

confidence: 99%

The Effect of Penicillin on the Methylene Blue Reduction Time and Keeping Quality of Milk

Rowlands¹

1951

Proceedings of the Society for Applied Bacteriology

Self Cite

View full text Add to dashboard Cite

Summary: The addition to 32 samples of freshly produced milk from 16 farms of 0.25, 0.5 and 1.0 unit/ml. of penicillin tended to increase the methylene blue reduction time at 37—38°, and to improve the keeping quality at 22°, irrespective of season. In no case was the reduction time decreased or the keeping quality made worse. In general, the effects were almost as marked with 0.25 unit as with the higher concentrations. The increases in the reduction time ranged from 0 to over 3 hr. in winter and from 0 to 2.5 hr. in summer. The delay in reaching the end‐point of the keeping quality test ranged from 0 to 15 hr. in winter and from 0 to over 18 hr. in summer. The response to penicillin differed with the two tests in individual samples. In some cases the methylene blue reduction time was markedly increased but keeping quality was little affected: in others, the reverse was observed. In both winter and summer streptococci predominated in the control samples at the keeping quality end‐point, but with penicillin added Gram‐negative rods often gained the ascendancy. At the time of reduction of methylene blue the flora of the winter control samples consisted mainly of streptococci and micrococci, but in the presence of penicillin the proportion of Gram‐negative rods generally increased: in summer Gram‐negative rods predominated in the control samples and in the presence of penicillin. Practically all the Gram‐negative rods were resistant to penicillin. All the micrococci and most of the streptococci were sensitive to penicillin; the resistant streptococci were strains of Str. faecalis. The variable distribution of resistant and sensitive organisms. coupled with the possible production of penicillinase, probably accounts for the variable effect of penicillin on the methylene blue and keeping quality tests in different samples.

show abstract

Section: Experimental Methodsmentioning

confidence: 99%

The Effect of Penicillin on the Methylene Blue Reduction Time and Keeping Quality of Milk

Rowlands¹

1951

Proceedings of the Society for Applied Bacteriology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Two-oz portions of milk were placed in a low temperature water bath a t 4 pm on the day of sampling and maintained at 22"&0*5" until the time of testing the following day. This was determined by the mean atmospheric shade temperature between 9 am and 4 pm on the day of sampling, according t o the scale suggested by Eddison et al (1951). Five ml of the sample were poured into a 6 x 9 in.…”

Section: Bacteriological Testsmentioning

confidence: 99%

Advisory Microbiological Standards and Tolerances for Raw Milk

Griffiths¹,

Druce²,

Thomas³

1957

Journal of Applied Bacteriology

View full text Add to dashboard Cite

To study the value of recent modifications of microbiological teflts used for advisory purposes, samples of tuberculin tested milk, taken at weekly intervals over a 5 year period from the Trawscoed Experimental Husbandry Farm and selected a t random during a 12 months period from farms in Wales, were examined by a temperature compensated keeping quality test at 2 2 O , colony count on Yeastrel milk agar in 3 days at 30' and coli-asrogenes colony count on violet red bile agar in 20-24 hr at 30".The results show that milk produced and handled under hygienic conditions can be expected to have colony counts of less than 2x104/ml and coli-mrogenes colony counts less than lO/ml when examined within 18 hr of milking.OVER THE past 30 years several workers in England have studied bacteriological tests suitable for use in advisory work for evaluating methods of milk production. Notable among them has been the work of Mattick (1930), Wilson et al. (1935), Clegg, Wohlgemuth, Crossley & Andrews (1949) and Clegg (1955).More recently Leech, Egdell & Thomas (1956) have described an investigation on a random sample of farms in England and Wales of methods of milk production, in conjunction with bacteriological and keeping quality tests of the milk. A statistical analysis of the results showed that of the many factors in milk production technique investigated, only the sterilization of utensils and the cooling of the milk showed any correlation with the keeping quality.The time is opportune to review the microbiological standards and tolerances used for advisory purposes, having regard to the changes in bacteriological techniques recently introduced in England and Wales. Among these has been the change of incubation temperature from 37" to 30" for the colony count and coli-aerogenes test and the use of a temperature-compensated keeping quality test by clot-onboiling (COB) at 22".The work reported in this paper was undertaken with a view to studying the value of these tests and t o suggest satisfactory levels related to the keeping quality of the milk. There is comparatively little information about the relationship of the colony count and coli-aerogenes test a t 30" to the keeping quality of farm milk supplies. METHODS Control milk samples from the Experimental Husbandry FarmBacteriological results for TT milk produced under good conditions were obtained with 78-24 hr old samples from the first 10 gal of milk over the equipment a t the

show abstract

“…The authors concluded, therefore, that temperature compensat,ioii may be applied to keeping quality results, or, in other words, that the results to be expected after storage at one temperature may be calculated from the results obtained after storage at any other temperature, the error being relatively small. Further data have been given by Rowlands & Hosking (1951).…”

Section: (F) Bacteriological Testing Aspectsmentioning

confidence: 99%

The Effect of Cold on Micro‐organisms in Relation to Dairying

Davis

1951

Proceedings of the Society for Applied Bacteriology

View full text Add to dashboard Cite

435. Keeping quality and raw-milk grading: II. The effect of storage on the results of keeping quality and dye tests

Cited by 16 publications

References 6 publications

The Effect of Penicillin on the Methylene Blue Reduction Time and Keeping Quality of Milk

The Effect of Penicillin on the Methylene Blue Reduction Time and Keeping Quality of Milk

Advisory Microbiological Standards and Tolerances for Raw Milk

The Effect of Cold on Micro‐organisms in Relation to Dairying

Contact Info

Product

Resources

About