Evaluation of the Microbial Quality of Raw Milk1

1987 ◽  
Vol 50 (1) ◽  
pp. 47-50 ◽  
Author(s):  
R. B. MAXCY ◽  
R. J. PAUL

Commercial evaluation of the microbial quality of raw milk presents a major challenge, and new methods are burdened by being compared to imprecise presently used standard methods. Extensive comparisons in commercial and research laboratory environments were made using a method that involved direct enumeration of single cells in comparison to colony forming units. The correlations were from 0.50 to 0.99 depending on treatment of the data. Repetition of all tests on milk from individual farms indicated that inherent variation in quality at the farm, sampling, testing, and evaluating the results showed the extreme inadequacy of the presently established methods of grading raw milk. More frequent tests with appropriate averaging would improve the likelihood of correct decisions on quality grade.

2015 ◽  
Vol 98 (12) ◽  
pp. 8572-8576 ◽  
Author(s):  
Emily M. Darchuk ◽  
Lisbeth Meunier-Goddik ◽  
Joy Waite-Cusic

1989 ◽  
Vol 52 (8) ◽  
pp. 549-551 ◽  
Author(s):  
L. B. SMITH ◽  
E. A. ZOTTOLA ◽  
T. L. FOX ◽  
K. CHAUSSE

Ninety vanilla frozen dessert mix samples were analyzed to determine total microbial populations and coliforms present in samples inoculated with a coliform isolated from raw milk. Standard methods agar (SMA, PCA, Difco) and violet red bile agar (VRBA, Difco) as well as Petrifilm™ (PSM, PVRB) were used for plating of samples. Standard VRBA 1:10 method produced significantly higher counts of colony-forming units (CFU) than PVRB 2:3 and VRBA 2:3 methods. VRBA 2:3 colony-forming unit counts were also significantly higher than those on PVRB 2:3, but both methods showed a moderately strong linear relationship. Repeatabilities of all three coliform plating methods (VRBA 1:10, VRBA 2:3, and PVRB 2:3) were acceptably low. Less than 10% of samples plated on SMA and PSM resulted in total aerobic colony-forming units in the countable range, making evaluation of data difficult and resulting in a lack of strong linear relationship between PSM and SMA. An additional 70 local retail store samples containing naturally occurring coliforms were evaluated using PVRB 2:3 and VRBA 1:10 methodology, confirmed in brilliant green lactose bile broth (BGLB, Difco) and compared to standard VRBA 1:10 previously analyzed. All methods were equivalent for mean log coliforms, i.e., 1.38,1.33, and 1.31 for PVRB 2:3, VRBA 2:3, and VRBA 1:10, respectively. Petrifilm™ methods were comparable to standard methods for enumerating coliforms in frozen dairy products, and would be a valid alternative to standard coliform and total plate count methods.


2016 ◽  
Vol 51 (2) ◽  
pp. 310
Author(s):  
Ahlam ElLeboudy ◽  
Amr Amer ◽  
Maria ElAansary ◽  
Hoda Sayed

2004 ◽  
Vol 67 (12) ◽  
pp. 2644-2650 ◽  
Author(s):  
R. N. ZADOKS ◽  
R. N. GONZÁLEZ ◽  
K. J. BOOR ◽  
Y. H. SCHUKKEN

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.


2020 ◽  
Vol 39 (01) ◽  
Author(s):  
Pankaj Kumar Gupta ◽  
Dinesh Chandra Rai ◽  
Vinod Kumar Paswan ◽  
Rajendra Panta ◽  
Ashok Kumar Yadav

The present study was conducted to evaluate the physico-chemical characteristics including Adulteration and Microbiological quality of cow raw milk collected from four different places of ASSI region in Varanasi. Samples were analysed to know the chemical composition, the results showed that the statistically average percentage of Moisture (87.46), Fat (3.87), Protein (3.15), Lactose (4.42), Ash (.712), pH (6.43) and acidity (0.147). The keeping quality of milk was evaluated by Methylene Blue Reduction Test (MBRT). This phenomenon testified that milk sample 1 is fair quality and remained sample were found good and excellent. The microbiological conclusion confirmed the presence (less or more) of microbial load in all the raw milk samples. The highest level of microbial quality in standard plate count (SPC) was 19.1×106 cfu/ml. in sample 1 and in logarithm value is 7.28 cfu/ml at the same time, the highest coliform bacteria 2.3×102 in logarithm value is 2.36 was found in the sample 2. The adulterations in raw milk were checked by the standard procedure. In cow’s raw milk the different mixed adulterant were found in two samples contaminated with detergent and pulverized soap. Besides different hazardous chemical adulterant, raw milk from sample 1 was detected with presence of hydrogen peroxide and sample 2 was contaminated formalin whereas urea was present in sample 2 and 4. Milk adulteration is a global concern and social problem. Increased demand, growth in competition in dairy industry and financial gain makes some producers to adulterate the milk thereby decreasing milk quality.


1993 ◽  
Vol 76 (4) ◽  
pp. 838-841 ◽  
Author(s):  
J L Rodrίguez-Otero ◽  
M Hermtoa ◽  
A Cepeda ◽  
C Franco

Abstract The BactoScan 8000 (Foss Electric) automatically performs a total count of bacteria in raw milk. It was designed for fast, repeatable counting. The apparatus counts the individual bacteria (IBC) instead of colony forming units (CFU). IBC provides more information on the state of milk hygiene than the CFU count. The repeatability, sr, was 0.033 log (IBC/μL), which is equivalent to a coefficient of variation of 7.9% (IBC/μL). The carryover, which is the contamination one sample imposes on the next, was 0.19%. The BactoScan 8000 was calibrated against the reference method of counting colonies on a Petri dish. The correlation coefficient for 429 milk samples was r= 0.88, and the standard deviation of the residuals, syx, was 0.259. The detection limit was 15 CFU/μL. We recommend establishing a system of payment to farmers based on the bacteriological quality of their milk as determined by the BactoScan 8000. Because results are obtained in IBC/μL, analytical differences resulting from conversion to CFU/|iL are eliminated.


Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1186
Author(s):  
Nicla Marri ◽  
Francesca Losito ◽  
Loris Le Boffe ◽  
Gilberto Giangolini ◽  
Simonetta Amatiste ◽  
...  

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.


Author(s):  
Nicla Marri ◽  
Francesca Losito ◽  
Loris Le Boffe ◽  
Gilberto Giangolini ◽  
Simonetta Amatiste ◽  
...  

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.


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