Effect of Low-Temperature Cleaning of Milking Equipment on the Microbiological Quality of Raw Milk

1983 ◽  
Vol 46 (1) ◽  
pp. 58-60 ◽  
Author(s):  
J. B. STONE ◽  
A. N. MYHR ◽  
I. DAVIE
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Negative Slope ◽  
Plate Count ◽  
Pipeline System ◽  
Standard Plate Count

Effect on the microbiological quality of milk of using a special cleaning detergent (Diversey-Wyandotte, Inc.) for low-temperature (initial 43.8°C, end of wash 35.4°C) washing in a milking parlor pipeline system was compared to regular high-temperature (initial 73°C, end of wash 43.8°C) wash of the system. Microbiological quality of the milk was determined by standard plate count (SPC) and psychrotrophic bacterial count (PBC). Cleanliness of equipment was evaluated by measurement of calcium deposits and visual inspection. Statistical analysis of data over time (June 5 to September 16, 1980) indicated no difference in SPC and PBC of milk between low-and high-temperature washing and, although there was a significant negative slope of PBC with time, this was due to factors other than treatment. Calcium soil deposition and visible evaluation of the equipment were not different for the wash temperatures.

scholarly journals Microbiological quality of raw milk attributable to prolonged refrigeration conditions

2017 ◽  
Vol 84 (1) ◽  
pp. 92-101 ◽  
Author(s):  
Nuwan R Vithanage ◽  
Muditha Dissanayake ◽  
Greg Bolge ◽  
Enzo A Palombo ◽  
Thomas R Yeager ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Storage Conditions ◽  
Storage Life ◽  
Plate Count ◽  
Industry Standard ◽  
And Storage

Refrigerated storage of raw milk is a prerequisite in dairy industry. However, temperature abused conditions in the farming and processing environments can significantly affect the microbiological quality of raw milk. Thus, the present study investigated the effect of different refrigeration conditions such as 2, 4, 6, 8, 10 and 12 °C on microbiological quality of raw milk from three different dairy farms with significantly different initial microbial counts. The bacterial counts (BC), protease activity (PA), proteolysis (PL) and microbial diversity in raw milk were determined during storage. The effect of combined heating (75 ± 0·5 °C for 15 s) and refrigeration on controlling those contaminating microorganisms was also investigated. Results of the present study indicated that all of the samples showed increasing BC, PA and PL as a function of temperature, time and initial BC with a significant increase in those criteria ≥6 °C. Similar trends in BC, PA and PL were observed during the extended storage of raw milk at 4 °C. Both PA and PL showed strong correlation with the psychrotrophic proteolytic count (PPrBC: at ≥4 °C) and thermoduric psychrotrophic count (TDPC: at ≥8 °C) compared to total plate count (TPC) and psychrotrophic bacterial count (PBC), that are often used as the industry standard. Significant increases in PA and PL were observed when PPrBC and TDPC reached 5 × 104cfu/ml and 1 × 104cfu/ml, and were defined as storage life for quality (SLQ), and storage life for safety (SLS) aspects, respectively. The storage conditions also significantly affected the microbial diversity, wherePseudomonas fluorescensandBacillus cereuswere found to be the most predominant isolates. However, deep cooling (2 °C) and combination of heating and refrigeration (≤4 °C) significantly extended theSLQandSLsof raw milk.

Effect of Low-Temperature Cleaning on Microbiological Quality of Raw Milk and Cleanliness of Milking Equipment on the Farm

1978 ◽  
Vol 41 (11) ◽  
pp. 902-906 ◽  
Author(s):  
DARRELL L. BIGALKE
Keyword(s):  
New York ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Solution Temperature ◽  
Plate Count ◽  
Psychrotrophic Bacteria ◽  
Standard Plate Count ◽  
Wash Solution ◽  
Standard Plate

Milking equipment on four farms each in the St. Paul. Minnesota area and the Ithaca, New York area was cleaned at wash solution starting temperatures of 120, 130, 140, 150, and 160 F. The effect of wash solution temperature on raw milk microbiological quality was determined by the Standard Plate Count (SPC), Psychrotrophic Bacteria Count (PBC). Coliform Count (CC) and Laboratory Pasteurized Count (LPC). Cleanliness of the farm milking equipment was determined by microbiological counts (SPC, PBC, CC) of circulated sterile water, visual examination and determination of residual calcium on the equipment. Statistical analysis of the data indicated that Klenzade farm detergents and Agway farm detergents can be used at temperatures such that the final wash solution temperature does not drop below 105 F and have no significant effect on cleaning performance, microbiological quality of raw milk or microbiological status of the milking equipment.

scholarly journals Rapid Microbiological Assessment in Raw Milk: Validation of a Rapid Alternative Method for the Assessment of Microbiological Quality in Raw Milk

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1186
Author(s):  
Nicla Marri ◽  
Francesca Losito ◽  
Loris Le Boffe ◽  
Gilberto Giangolini ◽  
Simonetta Amatiste ◽  
...  
Keyword(s):  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Plate Count ◽  
Microbiological Analysis ◽  
Biological Survey ◽  
Alternative Method ◽  
Colony Forming Units ◽  
Plate Count Method

The consumption of dairy products and the dairy industry are one of the main global agri-food sectors for its size, economic importance, and level of technology. Microbiological quality of pasteurized milk or other milk products is dependent on microbiological quality of raw milk. A variety of microbiological count methods is available for monitoring the hygienic quality of raw milk. Among them, the pour plate method is the official essay for counting the number of colony-forming units in milk samples according to International Organization for Standardization (ISO) No. 4833-1:2013. The aim of the present study is the validation of the Micro Biological Survey (MBS) method, against the reference plate-count method, for the assessment of the microbiological quality of raw milk. This comparative study, performed in collaboration with the Istituto Zooprofilattico Sperimentale del Lazio e della Toscana M. Aleandri (IZSLT), demonstrates the accuracy of this alternative method for the determination of total viable bacterial count in cow’s raw milk. The results obtained with the MBS method highlight its potential as a valid tool for reliable microbiological analysis in dairy industries.

scholarly journals Rapid Microbiological Assessment in Raw Milk. Validation of a Rapid Alternative Method for the Assessment of Microbiological Quality in Raw Milk.

2020 ◽  
Author(s):  
Nicla Marri ◽  
Francesca Losito ◽  
Loris Le Boffe ◽  
Gilberto Giangolini ◽  
Simonetta Amatiste ◽  
...  
Keyword(s):  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Plate Count ◽  
Microbiological Analysis ◽  
Biological Survey ◽  
Alternative Method ◽  
Colony Forming Units ◽  
Plate Count Method

The consumption of dairy products and the dairy industry is one of the main global agro-food sectors for size, economic importance and level of technology. Microbiological quality of pasteurized milk or other milk products is dependent on microbiological quality of raw milk. A variety of microbiological count methods is available for monitoring the hygienic quality of raw milk. Among them, the pour plate method is the official essay for counting the number of colony forming units in milk samples according to ISO 4833-1:2013. The aim of the present study is the validation of the Micro Biological Survey (MBS) method, against the reference plate count method, for the assessment of the microbiological quality of raw milk. This comparative study, performed in collaboration with the “Istituto Zooprofilattico Sperimentale del Lazio e della Toscana M. Aleandri” (IZSLT), demonstrates the accuracy of this alternative method for the determination of total viable bacterial count in cow’s raw milk. The results obtained with the MBS method highlighting its potential as a valid tool for reliable microbiological analysis in dairy industries.

Impact of Raw Materials and Processing Techniques on The Microbiological Quality of Egyptian Domiati Cheese

2020 ◽  
Keyword(s):  
Raw Materials ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Plate Count ◽  
E Coli ◽  
Fresh Cheese ◽  
Processing Techniques ◽  
The Impact ◽  
Total Yeast

Domiati cheese is the most popular brand of cheese ripened in brine in the Middle East in terms of consumed quantities. This study was performed to investigate the impact of the microbiological quality of the used raw materials, the applied traditional processing techniques and ripening period on the quality and safety of the produced cheese. Three hundred random composite samples were collected from three factories at Fayoum Governorate, Egypt. Collected samples represent twenty-five each of: raw milk, table salt, calf rennet, microbial rennet, water, environmental air, whey, fresh cheese, ripened cheese & swabs from: worker hands; cheese molds and utensils; tanks. All samples were examined microbiologically for Standard Plate Count (SPC), coliforms count, Staphylococcus aureus (S. aureus) count, total yeast & mould count, presence of E. coli, Salmonellae and Listeria monocytogenes (L. monocytogenes). The mean value of SPC, coliforms, S. aureus and total yeast & mould counts ranged from (79×102 CFU/m3 for air to 13×108 CFU/g for fresh cheese), (7×102 MPN/ cm2 for tank swabs to 80×106 MPN/ml for raw milk), (9×102 CFU/g for salt to 69×106 CFU/g for fresh cheese) and (2×102 CFU/cm2 for hand swabs to 60×104 CFU/g for fresh cheese), respectively. Whereas, E. coli, Salmonella and L. monocytogenes failed to be detected in all examined samples. There were significant differences in all determined microbiological parameters (p ≤0.05) between fresh and ripened cheese which may be attributed to different adverse conditions such as water activity, pH, salt content and temperature carried out to improve the quality of the product.

Rapid Detection of Psychrotrophic Bacteria In Manufacturing Grade Raw Milks

1991 ◽  
Vol 54 (11) ◽  
pp. 861-867 ◽  
Author(s):  
S. R. TATINI ◽  
P. MEKALA ◽  
A. EL-HABAZ ◽  
M. W. GRIFFITHS
Keyword(s):  
Rapid Detection ◽  
Bacterial Count ◽  
Raw Milk ◽  
Plate Count ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Microscopic Count ◽  
Direct Epifluorescent Filter Technique ◽  
Native Microflora

Methods to rapidly assess the bacteriological quality of raw milk were investigated. Whereas direct microscopic count, modified psychrotrophic plate count, and direct epifluorescent filter technique (DEFT) did not correlate well with initial psychrotrophic bacterial count of raw milk, improvements were obtained after preincubation of the milk samples. The best preincubation conditions were identified as 30°C for 6 h, 21°C for 10 h, 13°C for 15 h, 13°C for 20 h, or 7°C for 37 h. The “square root” equation was applied to the data, and a model was produced for predicting growth of the native microflora of raw milk. Using this equation, a DEFT count after preincubation of the milk at 21°C for 10 h could accurately predict the initial psychrotroph count and the count after storage of the milk at 6°C for 48 h.

Preliminary Incubation Count as an Index of Raw Milk Microbiological Quality During Storage

1984 ◽  
Vol 47 (3) ◽  
pp. 206-208 ◽  
Author(s):  
J. J. RYAN ◽  
R. H. GOUGH ◽  
C. H. WHITE
Keyword(s):  
Microbiological Quality ◽  
Storage Period ◽  
Raw Milk ◽  
Plate Count ◽  
Bacterial Counts ◽  
Sample Group ◽  
Psychrotrophic Bacteria ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate

During a 5-month period, 200 raw milk samples were collected from two Louisiana milk plants. Standard Plate Count (SPC), Psychrotrophic Bacteria Count (PBC), and Proteolytic Count (PC) of each sample were initially determined, then monitored daily during a 5-d storage period at 2.2°C. As hypothesized, all bacterial counts increased during the storage period. The magnitude of the increase in bacterial numbers during storage was further investigated by dividing the milk samples into bacteriologically acceptable and unacceptable groups based on SPC or Preliminary Incubation (PI) count. An SPC of 1.0 × 105/ml and PI counts of 1.0 × 105/ml, 1.5 × 105/ml, 2.3 × 105/ml, and 3.0 × 105/ml were used to repeatedly dichotomize the 200 raw milk samples into two groups. Median SPC, PBC, and PC for each acceptable and unacceptable group were then calculated. Dichotomization based on PI counts yielded acceptable sample groups having consistently lower bacterial counts during storage than did the acceptable sample group, which resulted from the dichotomization based on a SPC of 1.0 × 105/ml. The results of this study indicated that the PI count is of considerable value for raw milk quality control.

THE QUALITY OF RAW MILK FROM SELECTED OHIO MARKETS.

1966 ◽  
Vol 29 (4) ◽  
pp. 118-121 ◽  
Author(s):  
S. P. Ohri ◽  
W. L. Slatter
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
High Count ◽  
Coliform Count ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Bacteriological Method ◽  
Standard Plate ◽  
Bulk Tank

Summary An 8-month survey of the bacteriological quality of bulk tank produced fluid milk supplies for four major markets in Ohio, was made utilizing the Standard Plate Count (SPC), the preliminary incubation count (PI), the thermoduric (pasteurized milk) count, and the coliform count. In terms of maximum standards of 200,000 and 100,000 organisms/ml, the SPC would have eliminated 13% and 20% of the milk samples, respectively. A SPC of 50,000/ml, a PI count of 200,000/ml, a thermoduric count of 500/ml, and a coliform count of 100/ml would have eliminated 37%, 34%, 40%, and 40%, respectively, of the samples but not all of the samples eliminated by one test were eliminated by another test. All of the tests employed showed a seasonal trend especially in the high count categories but the trend was less noticeable in the results of the preliminary incubation count. A combination of two of the methods was superior to any single bacteriological method employed in detecting unsatisfactory milk. Of the tests used, the combination of the thermoduric count (500/ml) and the coliform count (100/ml) was the most effective in the detection of unsatisfactory milk samples.

Impedance Measurement as an Alternative to the Plate Count Method for Estimating the Total Count of Bacteria in Raw Milk

1987 ◽  
Vol 50 (8) ◽  
pp. 665-668 ◽  
Author(s):  
F. F. J. NIEUWENHOF ◽  
J. D. HOOLWERF
Keyword(s):  
Standard Deviation ◽  
Microbiological Quality ◽  
Impedance Measurement ◽  
Raw Milk ◽  
Plate Count ◽  
Impedance Method ◽  
Count Method ◽  
Plate Counts ◽  
Plate Count Method

An improved impedance method is described with a good standard deviation of repeatability (sm = 0.05 log unit) and a fair standard deviation of the estimate of the plate count from the detection time [(sy)x = 0.33 log unit]. Compared with the standard deviation of repeatability of the plate count method (0.07 log unit), the standard deviation of repeatability of the impedance method described is a significant improvement. The impedimetric experiments were done with a Bactometer M123. The detection times as measured by this instrument were compared with the plate counts at 30°C for samples of raw refrigerated farm milk. With this technique a good indication of the microbiological quality of raw milk can be obtained within 15 h.

scholarly journals Microbiological Profile of the Traditionally Collected Industrial Raw Milk from the Milk Pocket Zones of Bangladesh

1970 ◽  
Vol 25 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Gouranga C Chanda ◽  
Gazi M Noor Uddin ◽  
Aparna Deb ◽  
Tahmina Bilkis ◽  
Sharmin Chowdhury ◽  
...  
Keyword(s):  
Bacterial Count ◽  
Raw Milk ◽  
Total Coliform ◽  
Plate Count ◽  
Coliform Count ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Bacteriological Profile ◽  
Standard Plate ◽  
Viable Bacteria

The study was aimed to evaluate the bacteriological profile of the traditionally collected industrial raw milk from the milk pocket zones of Bangladesh. About 365 raw milk samples were collected from the milk tanker, who brought raw milk from the mother chilling centre where raw milk was chilled at 4°C following traditional method. All milk samples were subjected to perform standard plate count and total coliform count. The average standard plate count was found to be 4.37 x 106 cfu/ml and the highest occurrence of standard plate count was found to be 6.70 x 106 cfu/ml in October and the lowest (3.28 x 106 cfu/ml) in March. The highest occurrence of total viable bacteria was found to be 5.64 x 106 cfu/ml in autumn and the lowest was found to be 3.78 x 106 cfu/ml in summer. On the other hand, the average of the coliform bacterial count was found to be 3.88 x 105 cfu/ml with the highest (5.70 x 105 cfu/ml) occurrence in May and the lowest (1.90 x 105 cfu/ml) in January. Moreover, the highest occurrence of coliform count was found to be 4.84 x 105 cfu/ml in rainy season and the lowest was 2.75 x 105 cfu/ml found in winter.DOI: http://dx.doi.org/10.3329/bjm.v25i1.4849 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 17-20

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