CORRELATION BETWEEN STANDARD PLATE COUNT AND FOUR DIRECT MICROSCOPIC COUNT PROCEDURES FOR MILK

1966 ◽  
Vol 29 (12) ◽  
pp. 366-371 ◽  
Author(s):  
Roger Dabbah ◽  
W. A. Moats
Keyword(s):  
Acetic Acid ◽  
Toluidine Blue ◽  
Periodic Acid ◽  
Plate Count ◽  
Staining Procedure ◽  
Standard Plate Count ◽  
Bisulfite Treatment ◽  
Geometrical Pattern ◽  
Standard Plate ◽  
Microscopic Count

Summary The standard plate count (SPC-32 C) and the direct microscopic count (DMC) of samples of commercially pasteurized milk inoculated with pure cultures of actively growing (18–24 hr growth) bacteria commonly found in milk were compared. Four staining procedures for DMC were used: (a) Levowitz-Weber's methylene blue stain; (b) a modified Levowitz-Weber stain incorporating basic fuchsin; (c) alcoholic-acetic acid fixation followed by periodic acid-bisulfite treatment and staining with pH4 toluidine blue; and (d) alcoholic-acetic acid fixation and staining with pH4 toluidine blue. Counting was standardized by the use of a geometrical pattern. Correlations between SPC and each DMC procedure, or among the DMC procedures were little influenced by the number of microscopic fields counted, their location on the smear or the definition of “clumping” used. Correlations were influenced by the type of bacterial culture inoculated in milk and by the staining procedure. Precision of DMC was shown to be independent from the staining procedure, but varied directly with the number of cells per field and inversely with the square root of the number of fields counted.

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.

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.

EVALUATION OF PRODUCTION CONDITIONS OF MANUFACTURING-GRADE RAW MILK BY FIELDMEN RATINGS AND BY BACTERIAL TESTS

1971 ◽  
Vol 34 (4) ◽  
pp. 200-203 ◽  
Author(s):  
Roger Dabbah ◽  
W. A. Moats ◽  
J. C. Olson
Keyword(s):  
Correlation Coefficients ◽  
Raw Milk ◽  
Plate Count ◽  
Standard Plate Count ◽  
Reduction Test ◽  
Sanitary Condition ◽  
Methylene Blue Reduction ◽  
Standard Plate ◽  
Microscopic Count ◽  
Production Conditions

Standard microbiological tests, Standard Plate Count, direct microscopic count, methylene blue reduction test, and several variations of the resazurin reduction test were correlated with fieldmen's ratings of sanitary condition of milking area, milk house, and milking utensils. Correlation coefficients were low, in general, approximately 0.2. The effect of different production facilities and practices on these correlations was variable. Results suggest that bacterial tests and fieldmen's inspection be used concurrently since they appear to measure different sanitary factors on the producing farms.

Pyruvate in Producer and Commingled Manufacturing Grade Milk

1982 ◽  
Vol 45 (13) ◽  
pp. 1236-1241 ◽  
Author(s):  
R. T. MARSHALL ◽  
B. L. O'BRIEN ◽  
Y. H. LEE ◽  
W. A. MOATS
Keyword(s):  
False Negative ◽  
Skim Milk ◽  
Plate Count ◽  
Negative Type ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate ◽  
Microscopic Count ◽  
Highly Correlated

The automated test for pyruvate concentration, [P], was evaluated as a substitute for the direct microscopic count (DMC) in determining quality of manufacturing grade milk. Samples of manufacturing grade milk from producers and tank trucks as well as skim milk were collected at a large milk drying plant. Each sample was tested immediately for standard plate count (SPC), psychrotrophic plate count (PPC) and DMC. Portions of milk were heated to 85°C for 10 min to stabilize [P] before being returned to the laboratory for analysis of initial pyruvate concentration, [IP]. Unheated samples stored at 4°C were analyzed for [P] and DMC daily for up to 120 h. [IP] was a good indicator of PPC in milk from individual producers (r=0.81). However, [IP] was not highly correlated (r=0.26) with PPC in skim milk samples which were characteristically high in SPC and homogeneous in PPC. With skim milk, [IP] was more highly and significantly correlated with initial DMC (r=0.61) than with initial SPC (r=0.31) or initial PPC (r=0.26). [IP] was a good indicator of [P] in stored fluid samples until counts exceeded about 107/ml. Initial DMC and initial PPC were about equally correlated with [P] determined at 24-h intervals, and the initial DMC was a reasonably good indicator of DMC determined at 24-h intervals. Using 6.5 mg of pyruvate/L to represent bacterial counts of 3 × 106/ml by the three methods tested, the pyruvate test correctly classified 91% of 57 samples of producer milk based on PPC, 88% based on SPC and 82% based on DMC. Most of the error was of the false-negative type in which samples with high counts had less than 6.5 mg of pyruvate/L. This was probably because some bacteria catabolize pyruvate once their numbers exceed 107/ml.

scholarly journals Efek Dekontaminasi Karkas Ayam Pedaging Menggunakan Asam Asetat, Asam Sitrat dan Kombinasinya Terhadap Angka Lempeng Total Campylobacter sp.

2014 ◽  
Vol 14 (2) ◽  
pp. 96-101
Author(s):  
Zalhendra Eka Putra ◽  
Nurliana Nurliana ◽  
Razali Razali
Keyword(s):  
Acetic Acid ◽  
Citric Acid ◽  
Observation Time ◽  
Plate Count ◽  
Standard Plate Count ◽  
Total Plate Count ◽  
Standard Plate ◽  
Poultry Carcass ◽  
Treatment Observation ◽  
Banda Aceh

(Effect of poultry carcas decontamination by acetic acid, citric acid and its combination to total plate count of Campylobacter sp).ABSTRACT. This research aimed to detect the total number of Campylobacter sp. on poultry carcass after decontamination by acetic acid, citric acid and combination of both. This research was conducted in the Laboratory of Veterinary Public Health Syiah Kuala University, Banda Aceh. The research was factorial completely randomized designed. Samples of poultry carcass were obtained from the Lamnyong market, Banda Aceh. Sixty poultry carcasses were divided into three groups of treatment and one group without treatment. Observation of each treatment was five time replicated at 0, 2, 4, 6 and 8 hours after immersion for ± 30 seconds in each of the decontamination material. Observation of Campylobacter sp. was done by inoculating every sample on CM0739 selective Campylobacter Blood free selective agar base and CCDA Selective supplement SR0155E. Measurements of Total Plate Count (TPC) Campylobacter sp according to Standard Plate Count (SPC). Data was variance analyzed (ANOVA) using SPSS. The results of research showed that the growing colonies of Campylobacter sp. were indicated by white colony with surrounded by black zone. Immersion of poultry carcass with acetic acid, citric acid and combination of the both and the observation time had no influence (P0,05) to ALT Campylobacter sp. The research was concluded that carcass to Campylobacter sp. The immersion by acetic acid, citric acid and combination of both and the observation time were not reduce Campylobacter sp. in poultry carcass.  

Bioluminescence: A Rapid Indicator of Escherichia Coli O157:H7 in Selected Yogurt and Cheese Varieties

1997 ◽  
Vol 60 (8) ◽  
pp. 891-897 ◽  
Author(s):  
L. M. HUDSON ◽  
J. CHEN ◽  
A. R. HILL ◽  
M. W. GRIFFITHS
Keyword(s):  
Escherichia Coli ◽  
Enterohemorrhagic Escherichia Coli ◽  
Cottage Cheese ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Potential Hazard ◽  
Growth And Survival ◽  
E Coli ◽  
Standard Plate Count ◽  
Standard Plate

Outbreaks of enterohemorrhagic Escherichia coli O157:H7 have been commonly associated with products derived from ground beef, but recently the organism has been implicated as the causative agent in outbreaks involving yogurt and cheese. This finding has raised concern about the potential for its growth and survival in fermented dairy products. A bioluminescent strain of E. coli O157:H7 was used to determine postprocessing survival in yogurt with live cultures at pH 4.17, 4.39, and 4.47 stored at 4 and 10°C. In addition, survival of E. coli O157:H7 was monitored during the manufacture of Cottage, Colby, Romano, and Feta cheeses. Results indicated survival for 8 and 5 days at 4 and 10°C respectively in yogurt at pH 4.17, 17 and 15 days at 4 and 10°C respectively in yogurt at pH 4.39, and 17days at both 4 and 10°C in yogurt at pH 4.47. E. coli O157:H7 did not survive cooking procedures at 56°C in Cottage cheese. However, the pathogen survived for 27, 30, and 27 days in Colby, Romano, and Feta cheeses respectively. A high correlation of r2 > 0.89 was obtained between counts of bioluminescenct colonies and standard plate count for all yogurt and cheese varieties, indicating that bioluminescence was a sensitive and rapid indicator of cellular viability for E. coli O157:H7. Survival of the pathogen, as indicated by this method, is possible in highly acidic environments even at refrigeration temperatures. This poses a potential hazard should postprocessing contamination occur.

Evaluation of the 3M Dry Medium Culture Plate (Petrifilm™ SM) Method for Determining Numbers of Bacteria in Raw Milk1

1984 ◽  
Vol 47 (10) ◽  
pp. 753-755 ◽  
Author(s):  
R. E. GINN ◽  
V. S. PACKARD ◽  
T. L. FOX
Keyword(s):  
Cold Water ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
Water Soluble ◽  
Gelling Agent ◽  
Plate Count ◽  
Suitable Alternative ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Indicator Dye

The 3M Company has developed a sample-ready system (Petrifilm ™ SM) for enumerating bacteria in milk and other food products. The testing unit consists of Standard Methods culture medium coated onto a base film and overlaid with a second film coated with a cold-water-soluble gelling agent and tetrazolium indicator dye. As such, the system is ready to accept samples of product. A pipette or 0.001-ml plate loop continuous pipetting syringe can be used for applying samples. In this study, both methods of sample addition were used and results compared with those of the Standard Plate Count (SPC) and standard Plate Loop (PL) methods for determining bacteria numbers in raw milk. In total, 108 samples were analyzed in duplicate by each of the four methods. The correlation coefficients (r) between the 3M-SPC and SPC, 3M-PL and PL, 3M-PL and SPC and PL and SPC were 0.946, 0.935, 0.941, and 0.974, respectively. Repeatability, as measured by mean log10 variance for duplicate determinations, was essentially the same for the four methods, and in all instances less than 0.005. The mean log10 differences between the SPC and 3M-SPC, and SPC and 3M-PL were, respectively, −0.177 and −0.168. The preceding statistical criteria suggest the Petrifilm™ SM method to be a suitable alternative to the SPC or the PL procedure.

scholarly journals Comparison of Probiotic Isolate Growth in Natural Culture with Various Carbon Sources

2021 ◽  
Vol 6 (2) ◽  
pp. 103-107
Author(s):  
Sitti Nur Ilmiah ◽  
Zaraswati Dwyana ◽  
Asadi Abdullah
Keyword(s):  
Carbon Sources ◽  
Plate Count ◽  
Standard Plate Count ◽  
Standard Plate

Probiotik merupakan mikroba hidup yang memberikan pengaruh menguntungkan pada inang karena dapat menyeimbangkan mikroba yang ada dalam saluran pencernaan menjadi meningkat. Pemanfaatan tersebut dapat memberikan pengaruh positif dan kesehatan bagi inang sehingga sangat baik untuk diaplikasikan. Pemanfaatan bahan alami dapat menekan biaya media tumbuh sehingga perlu penggantian media sintetik dengan media alami karena memiliki harga yang relatif lebih murah tetapi mengandung nutrien penting bagi pertumbuhan mikroba. Tujuan penelitian ini adalah untuk mengetahui pertumbuhan isolat probiotik berdasarkan lama waktu kutur dalam media alami yang mengandung sumber karbon berbeda. Pertumbuhan isolat probiotik dalam berbagai sumber karbon dilakukan melalui metode Standard Plate Count (SPC). Melalui metode SPC didapatkan jumlah koloni isolat G dari masing-masing media berupa kanji, sagu, dan dedak yaitu 2,3 x 108 Cfu/mL, 6,4 x 106 Cfu/mL, dan 4,3 x 106 Cfu/mL selama 48 jam; 2,6 x 108 Cfu/mL, 1,6 x 108 Cfu/mL, dan 1,0 x 108 Cfu/mL selama 96 jam; 4,6 x 108 Cfu/mL, 1,8 x 108 Cfu/mL, dan 1,2 x 108 Cfu/mL selama 144 jam. Hasil yang didapatkan menunjukkan bahwa isolat G mampu ditumbuhkan dalam media alami berupa kanji, sagu dan dedak.

Microbiological Quality of Shellfish-Growing Waters in Chesapeake Bay

1994 ◽  
Vol 57 (3) ◽  
pp. 229-234 ◽  
Author(s):  
TUU-JYI CHAI ◽  
TZYY-JAN HAN ◽  
RALPH R. COCKEY
Keyword(s):  
Escherichia Coli ◽  
Chesapeake Bay ◽  
Water Samples ◽  
Microbiological Quality ◽  
Geographic Area ◽  
Water Area ◽  
Fecal Coliforms ◽  
Plate Count ◽  
Standard Plate Count ◽  
Standard Plate

A total of 338 water samples were collected at 20 stations from three geographically shellfish-growing areas in Chesapeake Bay from May to September 1989. Samples were examined for standard plate count, total coliforms, fecal coliforms, Escherichia coli and coliphages. Salinity, dissolved oxygen and temperature varied slightly with the depth, season, and geographic area of water samples. The geometric means of standard plate count for the three areas were 135, 355 and 275/ml, respectively. The range of means of fecal coliform for these areas was from <3 to 93/100 mi. Escherichia coli counts were also low with a range of <3 to 93/100 mi and a mean of < 3/100 mi. The growing water area adjacent to cropland was found to have higher bacterial counts than those of the other two areas. Levels of male-specific phages were very low. Results indicate that shellfish-growing waters in all three areas were of satisfactory bacteriological quality.

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