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.

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.

Determination of Viable Bacterial Populations in Raw Milk within 20 Minutes by Using a Direct Epifluorescent Filter Technique

1997 ◽  
Vol 60 (7) ◽  
pp. 874-876 ◽  
Author(s):  
CLAUDE P. CHAMPAGNE ◽  
NANCY J. GARDNER ◽  
JULIE FONTAINE ◽  
JACQUES RICHARD
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Bacterial Populations ◽  
Filter Technique ◽  
Milk Samples ◽  
Standard Plate ◽  
Plate Counts ◽  
Direct Epifluorescent Filter Technique ◽  
Triton X

The results from a shortened procedure for the direct epifluorescent filter technique (DEFT) determination of viable bacterial populations in raw milk were compared to standard plate counts. Shortening the prefiltration trypsin-Triton X-100 incubation period from 10 to 3 min enabled the completion of the analysis within 20 min. The short DEFT method results had a correlation coefficient (r) of 0.81 with plate counts. With respect to precision, the average difference between values of duplicate plate count analyses was 0.16 log units; that of the short DEFT was 0.14 log units. The slopes of the regressions equations were less than 1, indicating that a direct correlation is not achieved. Short DEFT values were 0.17 log units higher than those of plate counts on milk samples containing less than 10,000 CFU/ml. For milk samples containing counts over 10,000 CFU/ml, short DEFT values averaged only 0.05 log units above plate count readings. Daily preparation of the stain appears unnecessary since acridine orange solutions stored for up to 2 days at 4°C did not produce results significantly (P > 0.05) different from those obtained with fresh solutions. The short DEFT method has potential for the assessment of the bacteriological quality of raw milk in tanker deliveries.

Impedance Measurements in Raw Milk as an Alternative to the Standard Plate Count1

1982 ◽  
Vol 45 (1) ◽  
pp. 4-7 ◽  
Author(s):  
S. GNAN ◽  
L. O. LUEDECKE
Keyword(s):  
Yeast Extract ◽  
Geometric Mean ◽  
Raw Milk ◽  
Plate Count ◽  
Impedance Method ◽  
Microbial Count ◽  
Specific Detection ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate

Electrical impedance, using the Bactometer 32, was evaluated as an alternative method to the Standard Plate Count (SPC) to determine the initial microbial count of raw milk samples. The raw milk samples were obtained from farm bulk tanks on commercial dairy farms. Analyses were started within 24–36 h after collection. The impedance method was used to evaluate the samples as raw milk, raw milk plus yeast extract, raw milk given preliminary incubation (18 h at 13 C) or raw milk given preliminary incubation plus yeast extract. The yeast extract (1% final concentration) was added after the milk was placed in the module wells. The geometric mean SPC of each of these four groups was 4.51, 4.37, 4.96 and 5.14, and the corresponding mean detection times with Bactometer 32 were 10.13, 8.80, 8.28 and 6.11 h, respectively. The correlation coefficient of detection time to SPC was −0.77, −0.88, −0.78 and −0.79, respectively, for the four sample groups. When specific detection cut-off times (approximately 7 h) were selected and a maximum SPC of 100,000 CFU/ml was selected, 85.2%, 97.2%, 81.0% and 83.6%ofthe samples in the above four groups were correctly classified.

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.

Temperature Equilibration Times of Plate Count Agar and a Comparison of 50 Versus 45 C for Recovery of Raw-Milk Bacteria1

1975 ◽  
Vol 38 (6) ◽  
pp. 319-322 ◽  
Author(s):  
C. N. HUHTANEN ◽  
A. R. BRAZIS ◽  
W. L. ARLEDGE ◽  
C. B. DONNELLY ◽  
R. E. GINN ◽  
...  
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Equilibration Time ◽  
Standard Methods ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Plate Count Agar ◽  
Standard Plate ◽  
Time Required ◽  
Tempering Time

Sixty raw milk samples were plated using “Standard Methods” agar tempered to 45 or 50 ± 1 C. The standard plate count was significantly lower with the agar at 50 C. Tempering time (to 44–46 C) of a flask of agar in a water bath was about 5–10 min longer than that of a comparable flask of water. Time required to reach the desired temperature depended upon the volume of agar in the flasks, the number of flasks, and the volume of the water in the bath. Up to an hour of equilibration time may be necessary for newly autoclaved agar to reach the recommended temperature (44–46 C). Insufficient tempering time might cause an excessively high plating agar temperature which might cause a reduction in bacterial counts, especially of a heat sensitive psychrotrophic bacterium.

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.

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.

scholarly journals Multiregional Evaluation of the SimPlate Heterotrophic Plate Count Method Compared to the Standard Plate Count Agar Pour Plate Method in Water

2000 ◽  
Vol 66 (1) ◽  
pp. 453-454 ◽  
Author(s):  
R. Wayne Jackson ◽  
Karen Osborne ◽  
Gary Barnes ◽  
Carol Jolliff ◽  
Dianna Zamani ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Water Samples ◽  
Plate Count ◽  
Heterotrophic Plate Count ◽  
Plate Method ◽  
Standard Plate Count ◽  
Plate Count Agar ◽  
Count Method ◽  
Standard Plate ◽  
Plate Count Method

ABSTRACT A new SimPlate heterotrophic plate count (HPC) method (IDEXX Laboratories, Westbrook, Maine) was compared with the pour plate method at 35°C for 48 h. Six laboratories tested a total of 632 water samples. The SimPlate HPC method was found to be equivalent to the pour plate method by regression analysis (r = 0.95;y = 0.99X + 0.06).

A New Medium for Determining the Total Plate Count in Food

1999 ◽  
Vol 62 (12) ◽  
pp. 1404-1410 ◽  
Author(s):  
C. F. SMITH ◽  
D. E. TOWNSEND
Keyword(s):  
Linear Regression Analysis ◽  
Alternative Methods ◽  
Plate Count ◽  
Most Probable Number ◽  
Suitable Alternative ◽  
Probable Number ◽  
Standard Plate Count ◽  
Plate Count Agar ◽  
Total Plate Count ◽  
Standard Plate

SimPlate for Total Plate Count–Color Indicator (TPC-CI, IDEXX Laboratories, Inc., Westbrook, Me.) is a new medium that incorporates the redox dye resazurin to detect and quantify bacteria in food. Enumeration is achieved by the most probable number method using a SimPlate device. Viable bacteria are detected in each well of the SimPlate device by the biochemical reduction of resazurin, which is blue, to the pink resorufin or the clear dihydroresorufin indicators. Results after 24 h of incubation for TPC-CI are highly correlated with standard plate count agar after 48 h of incubation. Correlation coefficients from studies conducted at five laboratories ranged from 0.94 to 0.98 in side-by-side comparisons against standard plate count agar. Four additional test sites, using alternative methods for determining the aerobic plate count in food, reported similar results in comparison studies (r = 0.91 to 0.97). The slopes from linear regression analysis at all sites ranged from 0.91 to 0.98, with y intercepts ranging from 0.11 to 0.84. Samples used for the validation of TPC-CI included raw food products (i.e., liver and grains), which may contain natural enzymes that interfere with enzyme-based detection methods. No interference was seen from the foods tested. These results suggest that TPC-CI is a suitable alternative to existing plate count methods and has reduced incubation time.

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.

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