The Microflora of Steam Sterilized Milking Equipment

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Summary: The incidence of the main types of bacteria among 2,856 isolated on Yeastrel‐milk agar incubated at 30° from 121 rinses of dairy equipment cleansed by chemical methods, showed that micrococci were dominant in low colony count (<104/ft2) rinses of equipment treated by immersion cleaning in caustic soda or cleansed in detergent‐hypochlorite solutions, whereas nonpigmented Gram‐negative rods were dominant in low count rinses of equipment cleansed with detergent‐sterilizers containing quaternary ammonium compounds. Gram‐negative rods were dominant and streptococci frequent in high count (<2·5 × 105/ft2) rinses irrespective of the chemical used. A high proportion of the streptococci and coli‐aerogenes organisms gave acid reactions in litmus milk after 72 h at 22°, many of the anaerogenic Gram‐negative rods and several of the aerobic sporeformers gave proteolytic reactions, whereas the majority of the micrococci, corynebacteria and other asporogenous Gram‐positive rods showed no change. Bacteria isolated from high count rinses were more active in producing milk spoilage reactions at 22° than those isolated from low count rinses.

Section: Chlorine Disinfectionsupporting

confidence: 56%

Section: Immersion Cleaning In Caustic Sodamentioning

confidence: 99%

Section: Chlorine Disinfectionmentioning

confidence: 99%

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The Microflora of Milking Equipment Cleansed by Chemical Methods

Thomas¹,

Hobson²,

Elson³

1964

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“…The present paper, which deals with the microflora of poorly cleansed farm dairy equipment showing very heavy contamination, is a continuation of a previous series on the microflora of steam sterilized milking equipment and of chemically disinfected equipment (Thomas, Druce & King, 1964;Thomas, Hobson & Elson, 1964).…”

mentioning

confidence: 94%

The Microflora of Poorly Cleansed Farm Dairy Equipment

Thomas¹,

Druce²,

King³

1966

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A series of 170 rinses and 14 milk residue deposits from poorly clean& dairy equipment on 136 farms, giving colony counts a t 30" of > 106/ft' for rinses or /g wet w t for residues, were claasitied into 8 groups according to the composition and milk spoilage activity of their microflora. Five of the groups were dominated by active milk spoilage types of bacteria and three by inactive organisms. Micrococci, coryneform bacteria and aerobic sporeforming rods dominated the microflora of 1/3 of the 184 samples. Gram negative rods, including coli-aerogenes orgenismS, were dominant in another 1/3, e combination of micrococci, coryneform bacteria and Gram negative rods constituted the microflora of 19% and streptococci were dominant in 10%. Active milk spoilage types of bacteria were predominant in 106 (58%) of the rinses and deposits, but inactive types forming no reaction in litmus milk in 72 h at 22" were dominant in 78 (42%).

“…The composition of the microflora was studied by picking approximately 24 colonies from a sector chosen at random from a countable YMA plate, &B described by Thomas, Druce & King (1964), into yeast-dextrose-lemco broth (YDLB) and incubating at 30" for 24-72 h. Each YDLB culture was streaked on the surface of a dried YMA plate from which, after incubation at 30" for 24-48 h, a well isolated colony was traqsferred to two YMA slopes, one of which was incubated at 30" and the other at 22". The YMA slopes provided material for the following differential tests : Gram reaction and morphology, catalase production, pigment formation, fermentation of litmus milk at 22" and reaction in MacConkey's broth at 30".…”

Section: Methodsmentioning

confidence: 99%

The Microflora of Hand Washed Milk Bottles

Thomas¹,

King²,

Davies³

1966

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The examination of a series of 713 milk bottles cleansed by hand washing at producer-retailer farm dairies showed that though nearly 60% attained satisfactory bacteriological standards, about 30% gave high colony counts (> 600/bottle), while coli-esrogenes organisms were found i n 17% and milk spoilage organisms in 26% of them. The microflora of efficiently cleansed bottles, with colony counts of <200/bottle. waa dominated by micrococci and aerobic sporeforming rods. Only 3.7% of the 269 cultures from these bottles gave acid reactions i n litmus milk in 72 h at 22". Inefficiently cleansed bottles, with colony counts of >600/bottle, had quite a different type of microflora which was usually dominated by Gram negative rods (achrornobecteria, noduorescent pseudomonads and flavobacteria). A much higher proportion (19%) of the 393 cultures from these bottles gave acid reactions in litmus milk. P PI b E P, U 8 3. * After incubating at 30" for 72 h. t After hcUb8thg at 22" for 72h.