COMPARISON OF METHODS FOR GRADING MILK INTENDED FOR MANUFACTURING PURPOSES1,2

1967 ◽  
Vol 30 (3) ◽  
pp. 71-76 ◽  
Author(s):  
Roger Dabbah ◽  
Sita Ramayya Tatini ◽  
J. C. Olson
Keyword(s):  
Geographical Location ◽  
The United States ◽  
Plate Count ◽  
United States Department ◽  
Department Of Agriculture ◽  
Standard Plate Count ◽  
Class 1 ◽  
Standard Plate ◽  
Bulk Tank ◽  
Level Of Significance

Summary Samples of milk intended for manufacturing purposes were obtained once each season from randomly selected dairy farms in three widely separated geographical locations. Samples (3873) were analyzed by standard plate count (SPC-32 C), direct microscopic clump count (DMCC), methylene blue (MBRT) and resazurin (RRT), (5P 7/4) test. Correlations for SPC vs. DMCC, MBRT, and RRT were r = 0.78, −0.82 and −0.79, respectively; DMCC vs. MBRT, RRT, r = −0.75 and −0.68, respectively; MBRT vs. RRT, r = 0.86. Prediction of DMCC, MBRT, and RRT on the basis of their regressions with SPC Were influenced significantly (99% level of significance) by the geographical source of samples, the type of milk handling on the farm (can or farm bulk tank) and season. On the basis of equivalents (determined by regression) between classifying tests, new standards were developed. The percentage of samples classed the same by the four methods using these new calculated classifications or the classification recommended by the United States Department of Agriculture (USDA) was approximately 50% of all samples. Agreement between the four methods of classifying samples was not close enough to warrant the interchangeable use of the four tests. Results from calculated classifications varied considerably with geographical location and with the method of handling milk on the farm. Although the use of calculated classifications would give better agreement among the four methods when applied to the supplies from which they were derived, multiplicity of tests methods, their application and interpretation would cause much confusion. Use of the RRT with a 5P 7/4 Munsell color end-point with separate procedures, one for can supplies (RRT: > 2 1/2, ≤ 2 1/2, and ≤ 1 1/2 hr for Class 1, 2, and 3, respectively) and one for farm bulk tank supplies (RRT: > 3 1/2, ≤ 3 1/2, and ≤ 2 1/2 for Class 1, 2, and 3, respectively) resulted in grading milk, intended for manufacturing purposes, more uniformly than either use of the four classification methods interchangeably or even use of a single RRT standard based on all samples regardless of type of milk handling on the farm (can or bulk tanks).

Pyruvate as an Indicator of Quality in Grading Nonfat Dry Milk1

1982 ◽  
Vol 45 (6) ◽  
pp. 561-565 ◽  
Author(s):  
R. T. MARSHALL ◽  
Y. H. LEE ◽  
B. L. O'BRIEN ◽  
W. A. MOATS
Keyword(s):  
Geometric Mean ◽  
Regression Line ◽  
Skim Milk ◽  
Plate Count ◽  
Department Of Agriculture ◽  
Standard Plate Count ◽  
Geometric Average ◽  
Dry Milk ◽  
Standard Plate ◽  
Microscopic Count

Samples of skim milk and nonfat dry milk (NDM) made from it were collected, paired and tested for pyruvate concentration, [P], and Direct Microscopic count (DMC). The skim milk was tested for Standard Plate Count (SPC) and Psychrotrophic Plate Count (PPC). The geometric average DMC of skim milk was more than three times higher than that of the paired NDM samples. However, [P] of NDM was not significantly different from that of the skim milk. Although [P] of skim milk was poorly correlated with SPC and PPC, r = .31 and .26, respectively, it was relatively well correlated with DMC, r = .64. Data were widely dispersed around the regression line when [P] was ≤ 4.0 mg/L. However, [P] increased rapidly when DMCs were > 106/ml. A limit of 10 mg/L of [P] in NDM reconstituted 1:9 was chosen to represent the current U.S. Department of Agriculture Standard for DMC in NDM. This limit failed to classify about 10% of the samples correctly, assuming that each geometric mean DMC was correct. However, the probability that samples meeting the DMC standard would be rejected by the pyruvate test was quite low and the probability was moderate that samples which would be acceptable by the pyruvate test would be rejected by the DMC. For the latter, 28% of the samples having DMCs of ≥ 107/ml contained < 10 mg/L of pyruvate. No sample having ≥ 10 mg/L of pyruvate had a DMC of ≤ 107/ml. Pyruvate concentration in NDM did not change during storage at 5 or 32°C for 90 days.

scholarly journals Bruise Patterns of Fresh Market Apples Caused by Fruit-to-Fruit Impact

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 59
Author(s):  
Han Fu ◽  
Manoj Karkee ◽  
Long He ◽  
Jieli Duan ◽  
Jun Li ◽  
...  
Keyword(s):  
The United States ◽  
United States Department ◽  
Drop Height ◽  
Fresh Market ◽  
Department Of Agriculture ◽  
Class 1 ◽  
Bottom Zone ◽  
Free Drop ◽  
Different Levels ◽  
Fruit Surface

Comprehensive understanding of bruise damage caused by apple-to-apple impacts is beneficial to design a low-impact fruit capturing mechanism for mass (shake-and-catch) harvesting, as well as to design other fruit handling devices. This study quantified the bruising severity in ‘Jazz’ apples induced by different levels of impact upon various fruit surface locations. Impact experiments were carried out to analyze bruising patterns in three zones in a fruit surface, i.e., middle/cheek-to-top/stem, middle-to-middle and middle-to-bottom/calyx. Moving fruit and stationary fruit were impacted using a pendulum-type test device, and an equivalent drop height of fruit was calculated to provide a more practical measure for designing a catching surface. In each impact zone, seven different levels of impacts were applied respectively at seven different locations on the fruit surface. Those locations were evenly distributed along the circumferential direction in each of the three zones, and moving fruit was replaced after each impact test. The United States Department of Agriculture (USDA) standard was then used to estimate percentages of fruit in the Extra Fancy Class 1 (no bruising), Extra Fancy (a bruising area diameter ≤ 12.7 mm) and Fresh Market (a bruising area diameter ≤ 19 mm) grades. Results showed that fruit bruising severity increased in a non-linear manner with increasing drop height. It was also found that there existed significant differences in fruit bruising severity between stationary and moving fruit under different fruit-to-fruit impact zones. The bottom zone showed the least bruising sensitivity, followed by the middle zone which was statistically similar to the same in the top zone. The results suggested that the free drop height need to be <3 cm to keep from fruit bruising caused by apple-to-apple impact at a negligible level for ‘Jazz’ apples.

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.

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 &gt;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.

MICROBIAL COUNTS OF INDIVIDUAL PRODUCER AND COMMINGLED GRADE A RAW MILK1

1973 ◽  
Vol 36 (3) ◽  
pp. 146-151 ◽  
Author(s):  
H. E. Randolph ◽  
B. K. Chakraborty ◽  
Otto Hampton ◽  
D. L. Bogart
Keyword(s):  
Statistical Significance ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
Microbial Populations ◽  
Plate Count ◽  
Microbial Counts ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Bulk Tank ◽  
Highly Correlated

Microbial populations of Grade A raw milk samples from 105 individual producers and 74 bulk tank trucks (commingled) were enumerated by Standard Plate Count (SPC), psychrotrophic count (PBC), coliform count (CC), laboratory pasteurized count (LPC), thermophilic count (TBC), yeast and mold count (Y&M), and special penicillin (PEN) and crystal violet tetrazolium (CVT) agar count procedures. In addition, microbial populations were determined by the SPC, PBC, PEN, and CVT procedures after preliminary incubation (PI) of samples. Initial mean counts obtained on individual producer samples were generally lower than those for commingled samples. However, producer samples had higher mean counts after PI. Growth ratios were lower for commingled than for individual producer samples indicating slower growth during PI. Results obtained by the PBC, PEN, and CVT procedures were similar when viewed as correlation coefficients, distribution of samples according to microbial counts, mean counts, and growth ratios during PI. Before PI, the correlation between these three tests was poor and lacked statistical significance when the PBC was &lt;50,000/ml. After PI, the tests were highly correlated (P&lt;0.01) and the r values ranged from 0.8 to 0.9 for samples with PBC levels above 108/ml.

THE MICROFLORA OF RAW BULK TANK MILK

1966 ◽  
Vol 12 (3) ◽  
pp. 429-432 ◽  
Author(s):  
H. Jackson ◽  
L. F. L. Clegg
Keyword(s):  
Colony Count ◽  
Plate Count ◽  
Staining Reaction ◽  
Dominant Group ◽  
Standard Plate Count ◽  
Plate Count Agar ◽  
Gram Staining ◽  
Lactose Fermentation ◽  
Standard Plate ◽  
Bulk Tank

Milk samples from 141 farms were plated on standard plate count agar and the colony count determined after incubation for 48 hours at 32 °C. Twenty colonies were picked at random from plates containing between 30 and 300 colonies. The isolates were inoculated into litmus milk and subsequently characterized on the basis of shape, Gram-staining reaction, catalase production, lactose fermentation, and the ability to form spores.Certain general trends in the flora were observed. In milk of a colony count less than 2 × 104 per ml, micrococci were the dominant group of organisms, and as the colony count of the milk increased the percentage of micrococci decreased and the percentage of Gram-negative rods and streptococci usually increased. In spite of these general trends a study of the flora of individual samples showed that quite marked variations did occur.

An Update Survey of Bulk Tank Milk Quality in Vermont

1991 ◽  
Vol 54 (7) ◽  
pp. 549-553 ◽  
Author(s):  
JOHN J. GOLDBERG ◽  
JOSEPH W. PANKEY ◽  
PEGGY A. DRECHSLER ◽  
PATRICIA A. MURDOUGH ◽  
DIANTHA B. HOWARD
Keyword(s):  
Somatic Cell ◽  
Research Laboratory ◽  
Somatic Cell Count ◽  
Geometric Mean ◽  
Arithmetic Mean ◽  
Plate Count ◽  
Bulk Tank Milk ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Bulk Tank

Quality of Vermont bulk tank milk was first surveyed in 1985 as part of a statewide milk quality enhancement program. In a second survey conducted in 1990, bulk tank milk from 1,971 farms was sampled and tested for standard plate count, bacterial type and species distribution, and somatic cell count. Test results from 1,203 duplicate bulk tank milk samples were compared between five Vermont milk processors and the University of Vermont Quality Milk Research Laboratory. Arithmetic mean standard plate count conducted by processors was 2.3 × 104 CFU/ml in 1990 compared with 3.0 × 104 CFU/ml in 1985 (Geometric mean went from 1.3 × 104 CFU/ml in 1985 to 1.1 × 104 CFU/ml in 1990). Trypticase blood-esculin agar was used at the Quality Milk Research Laboratory to determine distribution of bacteria types and species. Comparison of results with a 1985 survey appeared to demonstrate a reduction in the percentage of farms with Streptococcus agalactiae from 47% to 32%. Frequency of other organisms increased with the majority being environmental organisms. Arithmetic mean total raw bacteria count on blood agar was 1.9 × 104 CFU/ml. Correlation between standard plate count and blood agar raw bacteria count was low. Arithmetic mean somatic cell count appeared to decline from 5.4 × 105 cells/ml in 1985 to 3.4 × 105 cells/ml in 1990 (Geometric mean went from 4.1 × 105 cells/ml in 1985 to 2.9 × 105 cells/ml in 1990). Correlation between somatic cell counts conducted by milk processors and the Quality Milk Research Laboratory was high.

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