The effect of udder preparation before milking and contamination from the milking plant on bacterial numbers in bulk milk of eight dairy herds

1990 ◽  
Vol 57 (3) ◽  
pp. 307-318 ◽  
Author(s):  
Charles H. McKinnon ◽  
G. John Rowlands ◽  
A. John Bramley
Keyword(s):  
Bacterial Count ◽  
Raw Milk ◽  
Poor Correlation ◽  
Dairy Herds ◽  
Relative Significance ◽  
Bacterial Counts ◽  
Bulk Milk ◽  
Bulk Tank ◽  
Milking Machine ◽  
One Year

SummaryThe effect of teat washing and drying on bacterial numbers in bulk milk was compared with that of no teat preparation in eight commercial herds over one year. Using in-line milk samplers, milk was collected at various points during its passage through the milking plant and the samples were used to establish the relative significance of the sources of contamination of raw milk. Teat washing and drying of cows housed during winter reduced the total counts by 40% and streptococcal and coliform counts by 50%. Bacterial counts were significantly lower in cows at pasture during the summer and there was no reduction in count due to teat washing and drying. Bacteriological counts increased at each stage as the milk passed through the milking machine. The milking equipment significantly increased the total colony count by between 2000 and 3000/ml, and the bulk tank added a further 1500 to 2000/ml. The mean rinse bacterial counts of the milking equipment were higher in summer than winter, averaging 4·4 x 107bacteria/m2compared with 3·5 x 107/m2respectively. Although this level of bacterial contamination of the equipment is high by current standards, very low bulk milk bacterial counts were nevertheless achieved, particularly in the summer. This confirms that organisms from this source are not a major contaminant of the bulk milk. There was a very poor correlation between rinse counts and the bulk milk bacterial count, but a strong correlation (0·98) between total and streptococcal counts of the bulk milk. The unreliability of the use of rinse techniques to assess the contribution of milking equipment to bacterial counts of raw milk is emphasized.

Proteolysis detection in milk: I. Interpretation of tyrosine value data for raw milk supplies in relation to natural variation, bacterial counts and other factors

1973 ◽  
Vol 40 (3) ◽  
pp. 371-381 ◽  
Author(s):  
H. S. Juffs
Keyword(s):  
Amino Acids ◽  
Trichloroacetic Acid ◽  
Natural Variation ◽  
Bacterial Count ◽  
Raw Milk ◽  
Atmospheric Temperature ◽  
Total Bacterial Count ◽  
Positive Relationships ◽  
Bacterial Counts ◽  
Bulk Milk

SummaryA method for detection of proteolysis in milk was evaluated. Amino acids and peptides soluble in trichloroacetic acid were estimated by the Lowry–Folin procedure with expression of results in terms of colour yield equivalent to that of tyrosine (the ‘tyrosine value’ (TV)). Some variables and alternatives in the method of estimation were investigated.TVs for milk freshly drawn from individual cows were extremely varied (0·31–0·92 mg/ml). TVs for samples of refrigerated milk from daily supply farms were in the range 0·40–0·58 mg/ml; no relationships between TV and bacterial counts were evident with these samples. With bulk refrigerated raw milk supplied to Brisbane for liquid consumption from country depots and local farms equipped with bulk vats, significant positive relationships were found between TV and total bacterial count (TBC) for supplies from some sources, but in no instance was a significant relationship found between TV and psychrotroph or proteolytic psychrotroph count. Significant positive relationships were found between TV of bulk milk supplies from some sources and atmospheric temperature, and between TBC of the supplies and atmospheric temperature. The significance of these various relationships for bulk milks is discussed.Natural variation in TV imposed limitations on reliability of the method to provide an index of proteolysis; in general the results indicated that its application was restricted to bulk milk cold-stored for at least 3 days.

BACTERIAL COUNTS OF BULK MILK FOR INTERSTATE SHIPMENT

1962 ◽  
Vol 25 (8) ◽  
pp. 240-247 ◽  
Author(s):  
A. Richard Brazis ◽  
Luther A. Black
Keyword(s):  
Bacterial Count ◽  
Raw Milk ◽  
Storage Tanks ◽  
Bacterial Counts ◽  
Bulk Milk ◽  
Three Samples ◽  
Break Up ◽  
Sanitary Conditions

During this investigation single samples were collected from 773 milk cans, three samples from each of 416 farm bulk tanks, six samples from each of 158 farm pick-up trucks, single samples from 49 storage vats, twelve samples from each of 98 transport trucks, and single samples from 77 storage tanks. Of the samples collected, 96% had counts under 200,000; 1.9% had counts of 200,000 – 300,000; 0.7% had counts of 300,000 to 400,000 and 1.4% had counts in excess of 400,000 per ml. The bacterial count finding on pumped milk indicated that milk passage through pumps did not appear to contribute to subsequent high counts through the break-up of bacterial clumps which may have been present. When bacterial counts were correlated with observations of the sanitary conditions of milk handling, the data reaffirmed that laxity in cleaning, bactericidal treatment or cooling will be reflected in the bacterial count and may result in the shipment of raw milk having counts in excess of 200,000 per ml.

scholarly journals Prevalence in Bulk Tank Milk and Epidemiology ofCampylobacter jejuniin Dairy Herds in Northern Italy

2014 ◽  
Vol 80 (6) ◽  
pp. 1832-1837 ◽  
Author(s):  
Valentina Bianchini ◽  
Laura Borella ◽  
Valentina Benedetti ◽  
Antonio Parisi ◽  
Angela Miccolupo ◽  
...  
Keyword(s):  
Raw Milk ◽  
Dairy Herds ◽  
Fecal Matter ◽  
Milk Samples ◽  
Bulk Milk ◽  
Milk Contamination ◽  
High Prevalence ◽  
Bulk Tank ◽  
Sequence Types ◽  
Bovine Feces

ABSTRACTThermotolerantCampylobacterspp. are frequently the cause of human gastroenteritis and have assumed more importance in Italy following the increased consumption of raw milk. Our objectives were to determine the prevalence and genotypes ofCampylobacterspp. in dairy herds and to investigate the possible sources of bulk milk contamination. Bulk milk from dairy herds (n= 282) was cultured forCampylobacterspp. andEnterobacteriaceae. At threeCampylobacter jejuni-positive farms, bovine feces, pigeon intestines, milk, and water points were also investigated. Isolates were identified by PCR and genotyped using multilocus sequence typing (MLST).C. jejuniwas detected in 34 (12%) bulk milk samples. The strains belonged to 14 sequence types, and the most common clonal complexes were CC-21, CC-48, and CC-403. No association was demonstrated between the presence ofC. jejuniand high levels ofEnterobacteriaceaein bulk milk. At the three farms examined,C. jejuniwas isolated from bovine feces (25/82 [30.5%]), pigeon intestines (13/60 [21.7%]), bulk milk (10/24 [41.7%]), and water points (4/16 [25%]). MLST revealed lineages that were common between milk and bovine feces but distinct between cattle and pigeons. In one herd,C. jejuniwith the same genotype was isolated repeatedly from bulk milk and a cow with an udder infection. Our results showed a high prevalence ofC. jejuniin bulk milk and suggested that udder excretion, in addition to fecal matter, may be a route of bulk milk contamination. MLST analysis indicated that pigeons are probably not relevant for the transmission ofC. jejunito cattle and for milk contamination.

Herd factors influencing free fatty acid concentrations in bulk tank milk

2019 ◽  
Vol 86 (2) ◽  
pp. 226-232 ◽  
Author(s):  
Lars Wiking ◽  
Martin Bjerring ◽  
Mette Marie Løkke ◽  
P. Løvendahl ◽  
T. Kristensen
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Production System ◽  
Onset Time ◽  
Raw Milk ◽  
Bulk Tank Milk ◽  
Bulk Milk ◽  
Milking Frequency ◽  
Technical Factors ◽  
Bulk Tank

AbstractFree fatty acid (FFA) concentrations can be elevated in raw milk due to improper handling and management at the dairy farm, and high concentrations of FFA can lead to off flavors in milk. This study aimed to describe how the herd production system, milking system, feeding and technological factors impact on FFA concentrations in bulk tank milk. FFA concentrations in bulk milk samples from 259 organic and 3326 conventional herds were analyzed by FT-IR during one year. The FFA content was significantly lower in bulk milk from organic than conventional herds. This was most evident during the summer half-year when the organic cows graze pasture. Bulk milk from automatic milking systems (AMS) and tie-stalls contained greater concentrations of FFA than any other milking parlor systems. In AMS, high milking frequency was found to be the most significant contributor to elevated FFA content in milk. Moreover, a strong interaction was found between milking interval and production system (organic vs. conventional). The technical factors, pre-cooling, onset time for cooling after milk inlet, contact between milk and agitation also impacted on the FFA concentration, whereas other technical factors including centrifugal pump type, length and height of pumping line and type of AMS manufacturer were found to be without significant effect on FFA. Feeding variables, based on feeding plans and evaluation, only explained a small part of the variation in bulk milk FFA. Overall, this study demonstrated that AMS compared to other milking system contributes significantly to increased FFA concentration in bulk tank milk, and within AMS high milking frequency contributes to increased FFA concentration.

Effect of Five Surface Area-to-Sample Volume Ratios During Preliminary Incubation on The Bacterial Count of Raw Milk1,2

1979 ◽  
Vol 42 (12) ◽  
pp. 968-970
Author(s):  
J. A. RITTER ◽  
B. E. LANGLOIS ◽  
J. O'LEARY
Keyword(s):  
Surface Area ◽  
Incubation Temperature ◽  
Bacterial Count ◽  
Raw Milk ◽  
Sample Volume ◽  
Bacterial Counts ◽  
Milk Samples ◽  
Standard Plate ◽  
Plate Counts ◽  
Incubation Temperatures

Effects of ratio of surface area to volume of sample during preliminary incubation (PI) and of different plate incubation temperatures on bacterial counts of raw milk samples were studied. One hundred and twenty Grade A raw milk samples collected during a 10-month period were divided into five 100-ml aliquots and allotted to one of five surface area to volume ratios. The ratios during PI ranged from 0 cm2/100 ml to 149.74 cm2/100 ml. Following PI, pour plates of each treatment were incubated at 26, 30 and 32 C for 72 h. The Standard Plate Counts (SPC) ranged from 89 × 101 to 20 × 108/ml, with the SPC of 73.6% of the samples being less than 1 × 105/ml. Counts after PI tended to be higher as the plate incubation temperature decreased from 32 to 26 C and as the ratio of surface area to volume of sample increased. None of the differences between the counts for the 15 treatment-incubation temperatures was significant. Counts of 61 samples increased less than one log count during PI, while counts of 33 and 16 samples increased one to two log counts and over two log counts, respectively. The greater the SPC, the smaller the increase in count during PI. Of the 81 samples with SPC less than 1 × 105/ml, 29 had counts after PI that exceeded 2 × 105/ml.

scholarly journals Source of Enterococci in a Farmhouse Raw-Milk Cheese

2002 ◽  
Vol 68 (7) ◽  
pp. 3560-3565 ◽  
Author(s):  
R. Gelsomino ◽  
M. Vancanneyt ◽  
T. M. Cogan ◽  
S. Condon ◽  
J. Swings
Keyword(s):  
Raw Milk ◽  
Streptococcus Bovis ◽  
Human Feces ◽  
Natural Habitats ◽  
Enterococcus Casseliflavus ◽  
Flavor Development ◽  
Bulk Tank ◽  
Milking Machine ◽  
Raw Milk Cheese ◽  
Almost All

ABSTRACT Enterococci are widely distributed in raw-milk cheeses and are generally thought to positively affect flavor development. Their natural habitats are the human and animal intestinal tracts, but they are also found in soil, on plants, and in the intestines of insects and birds. The source of enterococci in raw-milk cheese is unknown. In the present study, an epidemiological approach with pulsed-field gel electrophoresis (PFGE) was used to type 646 Enterococcus strains which were isolated from a Cheddar-type cheese, the milk it was made from, the feces of cows and humans associated with the cheese-making unit, and the environment, including the milking equipment, the water used on the farm, and the cows' teats. Nine different PFGE patterns, three of Enterococcus casseliflavus, five of Enterococcus faecalis, and one of Enterococcus durans, were found. The same three clones, one of E. faecalis and two of E. casseliflavus, dominated almost all of the milk, cheese, and human fecal samples. The two E. casseliflavus clones were also found in the bulk tank and the milking machine even after chlorination, suggesting that a niche where enterococci could grow was present and that contamination with enterococci begins with the milking equipment. It is likely but unproven that the enterococci present in the human feces are due to consumption of the cheese. Cow feces were not considered the source of enterococci in the cheese, as Enterococcus faecium and Streptococcus bovis, which largely dominated the cows' intestinal tracts, were not found in either the milk or the cheese.

COMPARISON OF PLATE LOOP AND AGAR PLATE METHODS FOR BACTERIOLOGICAL EXAMINATION OF MANUFACTURING GRADE RAW MILK1,2

1967 ◽  
Vol 30 (4) ◽  
pp. 112-115 ◽  
Author(s):  
Sita Ramayya Tatini ◽  
Roger Dabbah ◽  
J. C. Olson
Keyword(s):  
Agar Plate ◽  
Bacterial Count ◽  
Raw Milk ◽  
Substantial Improvement ◽  
Plate Count ◽  
Bacteriological Examination ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate ◽  
Bulk Tank

Summary Plate loop counts and standard plate counts on each of several manufacturing grade raw milk samples (handled in cans or in farm bulk tanks) have been compared. On the average, the plate loop count (PLC) was lower than the standard plate count (SPC) regardless of the type of handling of milk on the farm, can or bulk tank. Agreement between the SPC and PLC seemed to depend upon the bacterial-count levels present in milk. Statistical analyses indicated significant differences, at 1% level of probability, between the average bacterial count by SPC and PLC methods regardless of count level (≤100,000/ml or >100,000/ml) in case of can milk samples. On the other hand, in case of farm bulk tank milk samples, no significant differences, at the 1% level of probability, between the average bacterial count by SPC and PLC methods were obtained, when the counts were equal to or less than 100,000 per ml; when the counts exceeded 100,000 per ml, significant differences were present. Since the bacterial counts of manufacturing grade raw milk samples are likely to exceed 100,000/ml, the data presented in this investigation indicate that, until the bacteriological quality of manufacturing grade milk supplies undergoes substantial improvement, the PLC method does not appear to be a suitable substitute for the SPC method for routine bacteriological examination of such milk supplies.

COMPARISONS OF MASTITIS SCREENING TEST RESULTS FROM QUARTER, BUCKET AND BULK MILK SAMPLES1,2

1967 ◽  
Vol 30 (1) ◽  
pp. 7-12 ◽  
Author(s):  
D. S. Postle
Keyword(s):  
Test Scores ◽  
Screening Test ◽  
Dairy Farms ◽  
Screening Tests ◽  
Test Results ◽  
Milk Samples ◽  
Bulk Milk ◽  
Leukocyte Counts ◽  
Bulk Tank ◽  
One Year

Summary Milk from four dairy farms in southern Wisconsin was examined over a period of one year in a study that was undertaken: (a) to determine the agreement between results of mastitis screening tests when applied to bulk, bucket and quarter milk samples; (b) to determine the relative efficiencies of five mastitis screening tests using direct microscopic leukocyte counts as a standard, and (c) to examine the quality, as determined by leukocyte content and screening test results, of the milk from all quarters contributing to the bulk tank on each farm. Most screening tests examined, when applied to quarter milk samples, gave a higher correlation with direct microscopic leukocyte counts than when applied to either bucket or bulk milk samples. Similarly, efficiency ratings of screening tests applied to quarter samples were higher than those for the same tests applied to bulk samples. Three of the four farms examined maintained bulk tank milk screening test scores that failed to suggest the presence of milk from a substantial number of quarters that were shedding abnormal numbers of leukocytes.

scholarly journals Prediction of bovine milk true protein content by mid-infrared spectroscopy

2011 ◽  
Vol 41 (8) ◽  
pp. 1472-1474 ◽  
Author(s):  
Bruno Garcia Botaro ◽  
Cristina Simões Cortinhas ◽  
Lucinéia Mestieri ◽  
Paulo Fernando Machado ◽  
Marcos Veiga dos Santos
Keyword(s):  
Protein Content ◽  
Crude Protein ◽  
Bovine Milk ◽  
Dairy Herds ◽  
Protein Determination ◽  
Mid Infrared ◽  
Kjeldahl Method ◽  
Bulk Tank ◽  
One Year ◽  
True Protein

The aim of this study was to estimate the concentration of milk true protein (TP) by mid-infrared absorbance method (MIR) in samples from bulk tank of dairy herds, and to determine the correlation between the results of TP of milk determined by Kjeldahl and MIR. Forty nine dairy herds were selected (17 Holstein, 6 Jersey and 26 Girolando) for monthly collections of samples from bulk tanks during the period of one year (284 samples). Fat, lactose, crude protein and total solids were firstly determined by MIR, and then analyzed for total and true protein by Kjeldahl method. The regression equation to estimate TP contents based on MIR crude protein determination was as follows: TP=0.0021+(1.0104xCP), where: TP is the content of true protein, CP is the crude protein content determined by the MIR method, and 0.0155 is the model error term.

Mastitis-Causing Streptococci Are Important Contributors to Bacterial Counts in Raw Bulk Tank Milk

2004 ◽  
Vol 67 (12) ◽  
pp. 2644-2650 ◽  
Author(s):  
R. N. ZADOKS ◽  
R. N. GONZÁLEZ ◽  
K. J. BOOR ◽  
Y. H. SCHUKKEN
Keyword(s):  
New York ◽  
New York State ◽  
Raw Milk ◽  
Microbial Quality ◽  
Bulk Tank Milk ◽  
Gram Negative ◽  
Bacterial Counts ◽  
York State ◽  
Bulk Tank

The objective of this study was to probe the contribution of streptococci to the microbial quality of raw milk. Over a 5-month period, bulk tank milk samples from 48 New York State dairy farms were analyzed qualitatively for bacterial ecology and quantitatively for total bacterial, streptococcal, staphylococcal, and gram-negative bacterial counts. Linear regression analysis was used to determine the contribution of differential counts to total bacterial counts. Streptococci, staphylococci, and gram-negative bacteria accounted for 69, 3, and 3% of total bacterial count variability, respectively. Randomly selected Streptococcus isolates from each bulk tank milk sample were identified to species by means of the API 20 STREP identification system. The most commonly identified streptococcal species were Streptococcus uberis, Aerococcus viridans, and Streptococcus agalactiae, which were detected in 81, 50, and 31% of 48 bulk tank samples, respectively. For five herds, S. uberis isolates from bulk tank milk and individual cows were characterized by PvuII ribotyping. A farm-specific dominant ribotype was found in each bulk tank sample, and that ribotype was isolated from at least one cow within each herd of origin. Bacteriological and strain typing data indicate that control of streptococci, specifically mastitis-causing species, is important for improvement of the microbial quality of raw milk in New York State.

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