A COMPARISON OF THE EFFECT OF FOUR MILKING MACHINE CLEANING AND SANITIZING PROCEDURES ON THE STANDARD PLATE COUNT OF RAW MILK1

1955 ◽  
Vol 18 (11) ◽  
pp. 284-287
Author(s):  
G. H. Watrous ◽  
E. M. Kesler ◽  
H. V. Atherton
Keyword(s):  
Quaternary Ammonium ◽  
Statistical Difference ◽  
Plate Count ◽  
Standard Plate Count ◽  
Dry Storage ◽  
Standard Plate ◽  
Plate Counts ◽  
Milking Machine ◽  
Water Rinse ◽  
Rack Storage

A study of four milking machine washing and/or sanitizing methods indicates that an adequate washing procedure using the proper alkaline detergent, coupled with dry storage and a warm water rinse before use was as satisfactory as chlorine sanitizing, the use of a quaternary ammonium cleaner sanitizer, or lye rack storage. The plate counts obtained on milk where machines were thus treated showed no statistical difference attributable to the method employed.

Effect of Delayed Heading on Some Quality Attributes of Penaeus Shrimp1

1979 ◽  
Vol 42 (5) ◽  
pp. 407-409 ◽  
Author(s):  
R. J. ALVAREZ ◽  
J. A. KOBURGER
Keyword(s):  
Panel Data ◽  
Storage Period ◽  
Plate Count ◽  
Sensory Panel ◽  
Bacterial Populations ◽  
Standard Plate Count ◽  
Plate Count Agar ◽  
Pseudomonas Species ◽  
Standard Plate ◽  
Plate Counts

To determine the effect of delayed heading on shrimp quality, shrimp were stored on ice with and without heads for 10 days. Some shrimp were delay-headed after 5 days and returned to ice for the remainder of the storage period. Microbiological studies were conducted at 0, 5 and 10 days of storage. Total aerobic plate counts were done using Standard Plate Count agar with an added 0.5% NaCl. Incubation was at 20 C for 5 days. Analyses indicated similar counts on shrimp tails stored with or without heads and those delayed-headed. Counts ranged from 2.4 × 106 bacteria/gram at 0 day to 1.6 × 109 bacteria/gram on the 10th day. Identification of the flora present revealed that the same major groups of organisms predominated on shrimp tails subjected to the different storage treatments and the head did not alter development of the usual flora. Flavobacterium, Pseudomonas, Planococcus, Moraxella and the Vibrio/Aeromonas group were the major genera encountered. A shift in bacterial populations was observed during storage. Flavobacterium species predominated during the first 5 days of storage; however, after the fifth day Pseudomonas species predominated. Sensory panel data revealed no differences in acceptability between shrimp tails stored with or without heads and those delay-headed.

Biogenic Amine Survey and Organoleptic Changes in Fresh, Stored, and Temperature-Abused Bluefish (Pomatomus saltatrix)

1999 ◽  
Vol 62 (9) ◽  
pp. 1033-1037 ◽  
Author(s):  
TODD M. GINGERICH ◽  
TATIANA LORCA ◽  
GEORGE J. FLICK ◽  
MERLE D. PIERSON ◽  
HAROLD M. McNAIR
Keyword(s):  
High Performance Liquid Chromatography ◽  
Biogenic Amine ◽  
High Performance ◽  
Plate Count ◽  
Pomatomus Saltatrix ◽  
Morganella Morganii ◽  
Standard Plate Count ◽  
Histamine Formation ◽  
Standard Plate ◽  
Plate Counts

Changes in histamine, putrescine, and cadaverine concentrations in bluefish filets (Pomatomus saltatrix) stored at 5, 10, and 15°C were determined using high-performance liquid chromatography. An organoleptic assessment was conducted simultaneously with the biogenic amine analyses. The histamine levels found in fresh bluefish obtained from wholesale seafood distributors ranged between <1 ppm and 99 with an average of 39 ppm. Putrescine and cadaverine were not found in fresh bluefish. Fish fillets stored at each of the three temperatures developed histamine. The greatest accumulation of histamine was observed in fish stored at 15°C, which developed histamine levels as high as 2,200 ppm. Putrescine levels increased at each temperature during storage. Cadaverine was present only in uninoculated bluefish stored at 15°C. Histamine achieved higher levels in bluefish pieces inoculated with Morganella morganii, which demonstrates that bluefish support bacterial histamine formation. Histamine levels at each temperature exceeded the 50-ppm advisory level established by the Food and Drug Administration before 100% sensory rejection. Standard plate counts increased during storage of fish at all temperatures, but the correlation between histamine levels and standard plate count was not significant.

A COMPARATIVE EVALUATION OF OFFICIAL METHODS FOR THE STANDARD PLATE COUNT OF CREAM

1972 ◽  
Vol 35 (12) ◽  
pp. 730-732
Author(s):  
A. R. Brazis ◽  
J. W. Messer ◽  
J. T. Peeler
Keyword(s):  
Statistical Analysis ◽  
Comparative Evaluation ◽  
Plate Count ◽  
Precise Method ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Plate Counts

Three official methods to measure cream samples for Standard Plate Counts (SPC) were reviewed. A statistical analysis was made of results from 135 analysts over a 2-year period. Results demonstrated that: (a) pipetting samples is the least precise method to prepare cream samples for the SPC, (b) when compared to the SPC variance of 0.012, variation among analysts is significant for the procedure that weighs 11 g of cream, while the among-analyst variance is not significant when the 1-g weighing procedure is employed, and (c) weighing 1 g of cream is the most precise method to prepare cream samples for SPC determinations.

A Comparison of Phosphate Buffered and Distilled Water Dilution Blanks for the Standard Plate Count of Raw-Milk Bacteria1

1975 ◽  
Vol 38 (5) ◽  
pp. 264-268 ◽  
Author(s):  
C. N. HUHTANEN ◽  
A. R. BRAZIS ◽  
W. L. ARLEDGE ◽  
C. B. DONNELLY ◽  
R. E. GINN ◽  
...  
Keyword(s):  
Phosphate Buffer ◽  
Dairy Products ◽  
Raw Milk ◽  
Plate Count ◽  
Sign Test ◽  
Distilled Water ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Plate Counts ◽  
Water Dilution

Raw milk samples were diluted with distilled water or distilled water with added phosphate buffer as recommended by Standard Methods for the Examination of Dairy Products. The standard plate counts were higher in diluent without phosphate buffer with both high and low count milk. The higher counts were significant when analyzed by a nonparametric sign test or a t-test of differences but were not significant with an analysis of variance technique. Reproducibility was not statistically different in the two diluents. It is suggested that the use of phosphate buffer for raw milk bacteria counts be discontinued until information showing definite advantages is provided.

COMPARISON OF THE OVAL TUBE WITH THE STANDARD PLATE COUNT METHOD FOR DETERMINI NG VIABLE COUNTS OF RAW MILK

1966 ◽  
Vol 29 (6) ◽  
pp. 191-196
Author(s):  
S. G. Wilson
Keyword(s):  
Goodness Of Fit ◽  
Raw Milk ◽  
Plate Count ◽  
Chi Square ◽  
Standard Plate Count ◽  
Significant Difference ◽  
Standard Plate ◽  
Plate Counts ◽  
Comparison Of The Results ◽  
Oval Tube

Summary Standard plate counts (SPC) and oval tube counts (OTC) were compared and analyzed by the statistical method on 547 samples of raw milk from the Wichita milk shed. 389 of these milks were paired as routine two-dilution standard plates vs. single tube estimates of viable bacteria; 127 were set in duplicate by each method; and 31 samples were set in replicates of five for the purpose of two-factor variance analysis. Using the criterion of the IAMFES Committee on Applied Laboratory Methods, the experimental results indicated that the comparison odds were approximately even for equivalent counts between methods (48.9% of samples); two out of five random samples showed that the oval tube counts were higher (39.6% of samples) and that one out of ten of the standard plate counts was superior (11.5% of samples). Also, revised data of differences between two-dilution SPC's and single OTC's that passed the chi-square test for goodness of fit for a normal distribution gave a significant difference of means at the 1% level (89 samples). However, with another trial run, two-factor analysis did not yield a significant difference between methods (33 samples × 5 replicates), and the F ratio of the means of the pooled variance data showed no difference in precision between methods; the interaction between samples and methods was highly significant. A comparison of the results from these experiments with data obtained in five other laboratories over a span of 25 years is shown in Table form. It was concluded that there is no significant difference between the two methods where paired estimates are based on replication, but the oval tube is preferred where time and economy are important.

MANUFACTURING MILK QUALITY: A RE-EVALUATION

1971 ◽  
Vol 34 (5) ◽  
pp. 249-255 ◽  
Author(s):  
William S. LaGrange
Keyword(s):  
Milk Quality ◽  
Plate Count ◽  
Dairy Farmers ◽  
High Count ◽  
Psychrotrophic Bacteria ◽  
Standard Plate Count ◽  
Processing Plants ◽  
Standard Plate ◽  
Plate Counts ◽  
Microscopic Count

The bacteriological quality of manufacturing-grade milk is very similar to that marketed a decade earlier when bulk tanks first came into general use. Milk grading programs usually relied on reduction tests. These tests indicated that most milk supplies were good quality. Based on the Standard Plate Count, data is presented that show approximately one-third of the samples tested, in 1969–70 and in 1957–59, exhibit counts <200,000/ml. Considerable quantities of milk, received at processing plants have plate counts exceeding 1,000,000/ml. Dairy farmers learned they could substitute cooling for cleaning because psychrotrophic bacteria predominated the microflora of most high count bulk milk. These bacteria do not readily reduce resazurin and methylene blue. Psychrotrophs also tend to grow in clumps preventing an accurate evaluation of milk quality using the Direct Microscopic Count (DMC). USDA uses the DMC to test check manufacturing plant's milk supplies. Laboratories are recognizing the value of plating procedures, including the Plate Loop Count, to determine milk quality. Manufacturing-grade milk must be evaluated with a plating procedure before progress can be made in milk quality improvement. One grade of milk is far from being a reality if present levels of manufacturing-grade milk quality are considered.

PREDICTION OF STANDARD PLATE COUNT OF MANUFACTURING-GRADE RAW MILK FROM THE PLATE LOOP COUNT1

1970 ◽  
Vol 33 (4) ◽  
pp. 168-170 ◽  
Author(s):  
Earl O. Wright ◽  
George W. Reinbold ◽  
Leon Burmeister ◽  
James Mellon
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Adjustment Factor ◽  
Bacterial Counts ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Count Range ◽  
Standard Plate ◽  
Plate Counts

Plate Loop Counts and Standard Plate Counts of manufacturing grade raw milk samples were compared. With bacterial counts of 200,000/ml and less, the Plate Loop Count approximated the Standard Plate Count very closely. With counts greater than 200,000, the agreement was not as close. Differences between counts from the two methods, however, were not statistically significant (P<0.05) within either count range. An adjustment factor was determined to enable the Plate Loop Count to more accurately predict the Standard Plate Count of milk with a Standard Plate Count >200,000/ml. The Standard Plate Count can be reasonably predicted from the Plate Loop Count by the formula:

Analyst Variation in Doing the Standard Plate Count as Described in Standard Methods for the Examination of Dairy Products1,2

1978 ◽  
Vol 41 (1) ◽  
pp. 4-7 ◽  
Author(s):  
JAMES L. FOWLER ◽  
WARREN S. CLARK ◽  
JAMES F. FOSTER ◽  
ALAN HOPKINS
Keyword(s):  
Dairy Products ◽  
Plate Count ◽  
Bacterial Colony ◽  
Bacterial Counts ◽  
Standard Methods ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Plate Counts

Five analysts participated in a study to evaluate the following aspects of the 13th edition of Standard Methods for the Examination of Dairy Products (SMEDP): (a) analyst variation in overall Standard Plate Counts (SPC), and (b) analyst duplication of bacterial colony counts on agar places. Each analyst prepared 24 samples of pasteurized, homogenized milk during a successive 8-day period (i.e., 3 samples/day), and then the analysts estimated the numbers of bacterial colonies for these, as well as other analysts' plates, initially after 48 h of incubation, and then 1 h later and 24 h later. Statistically significant differences in colony enumerations were found between analysts in preparation of agar plates on 3 days. Significant differences were also noted between analysts for bacterial counts of agar plates. Mean bacterial estimates of certain analysts ranged between 565 and 948, and fluctuated greatly between the initial, 1-h, and 24-h determinations. These results indicate that the “standards of accuracy” currently specified in SMEDP are not realistic, i.e., (a) among-analyst variation of 18.2% compared to 10%, and (b) within-analyst variation of 7.7% compared to 5% in SMEDP.

An estuarine agar medium for enumeration of aerobic heterotrophic bacteria associated with water, sediment, and shellfish

1980 ◽  
Vol 26 (11) ◽  
pp. 1366-1369 ◽  
Author(s):  
Ronald M. Weiner ◽  
David Hussong ◽  
Rita R. Colwell
Keyword(s):  
Yeast Extract ◽  
Heterotrophic Bacteria ◽  
Agar Medium ◽  
Plate Count ◽  
Bacterial Populations ◽  
Standard Plate Count ◽  
Plate Count Agar ◽  
Standard Plate ◽  
Plate Counts ◽  
Yeast Extract Agar

A plate count agar was formulated for use in bacteriological analysis of estuarine samples and was tested together with standard plate count agar and an estuarine salts yeast extract agar for growth of aerobic, heterotrophic bacteria in water, sediment, and oysters. The estuarine agar was found to be efficient for enumerating aerobic, heterotrophic bacterial populations of water, sediment, and oysters, and is recommended for plate counts of estuarine samples.

THE RELATIONSHIP OF AVERAGE STANDARD PLATE COUNT RATIOS TO EMPLOYEE PROFICIENCY IN PLATING DAIRY PRODUCTS

1956 ◽  
Vol 19 (12) ◽  
pp. 336-344 ◽  
Author(s):  
J. L. Courtney
Keyword(s):  
Dairy Products ◽  
Plate Count ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Plate Counts ◽  
The Individual ◽  
Relationship Of ◽  
Effective Supervision

A study of the conditions under which 32,546 samples of dairy products were plated and 2,264 ratios occurred emphasizes the role of the individual worker and effective supervision in attaining maximum accuracy when making standard plate counts. It appears that the average ratio varies directly with the accuracy with which the procedure, particularly pipetting, is performed. Consequently, the average is an index to the quality of work being done.

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