Effect of Stored Pre-Poured Plates on Microbial Enumeration Using the Surface Plate Method1

1980 ◽  
Vol 43 (8) ◽  
pp. 592-594 ◽  
Author(s):  
J. E. KENNEDY ◽  
P. E. PHILLIPS ◽  
J. L. OBLINGER
Keyword(s):  
Correlation Coefficients ◽  
Storage Period ◽  
Regression Coefficients ◽  
Plate Count ◽  
Plate Method ◽  
Plate Count Agar ◽  
Plastic Bags ◽  
Plate Counts ◽  
Microbial Enumeration ◽  
Surface Plate

The surface plate method, using freshly pre-poured agar plates and/or stored pre-poured plates and the pour plate method were compared for enumeration of microorganisms in fresh bologna, fresh ground beef, frozen turkey pot pie and bacterial suspensions of Pseudomonas fluorescens and Streptococcus faecalis. Stored pre-poured Plate Count Agar (PCA) plates were packaged in plastic bags and held at 5 C for up to 6 weeks before use. Aerobic plate counts were derived from plates incubated at 35 C for 48 h, 20 C for 5 days and 7 C for 10 days. Differences in counts between methods for a given sample, incubation and pre-poured plate storage period were less than 0.5 log cycle in 97% of the comparisons. Regression and correlation coefficients between methods were highly significant; correlation coefficients varied from 0.987 to 0.999, and regression coefficients from 0.977 to 1.068 between any pair of methods. Storage of pre-poured plates for up to 6 weeks appeared to have no significant effect on recovery of microorganisms, using the surface plate technique.

Comparison of the Petrifilm™ Yeast and Mold Culture Film Method to Conventional Methods for Enumerating Yeasts and Molds in Foods

1991 ◽  
Vol 54 (6) ◽  
pp. 443-447 ◽  
Author(s):  
L. R. BEUCHAT ◽  
B. V. NAIL ◽  
R.E. BRACKETT ◽  
T. L. FOX
Keyword(s):  
Correlation Coefficients ◽  
Food Group ◽  
Black Pepper ◽  
Plate Count ◽  
Food Groups ◽  
Plate Count Agar ◽  
Plate Counts ◽  
Yeasts And Molds ◽  
Potential Food ◽  
Film Method

Petrifilm™ Yeast and Mold (YM) plates were compared to acidified potato dextrose agar (APDA) and chloramphenicol-supplemented plate count agar (CPCA) for its suitability to enumerate yeasts and molds in 13 groups of food products. These products consisted of beans (dry and frozen, green), corn meal, flour (wheat), fruit (apple), a meat/vegetable entree (chicken pot pie), a precooked meat (beef), milk (dehydrated, nonfat), nuts (pecans), pasta, potatoes (dehydrated), precooked sausage, and a spice (black pepper). Correlation coefficients of Petrifilm™ YM plates versus APDA and CPCA pour plates for recovering total yeasts and molds from a composite of the thirteen test foods were, respectively, 0.961 and 0.974. Individually, Petrifilm™ YM plate counts were equivalent or higher than APDA and CPCA for some food groups and lower for other food groups. Because food particle interference can make enumeration of yeast and mold colonies on Petrifilm™ YM plates difficult for some food groups, potential food interference will need to be evaluated for each food group tested.

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.

Chemical and Microbial Changes in Dehulled Confectionery Sunflower Kernels during Storage Under Controlled Conditions

1976 ◽  
Vol 39 (1) ◽  
pp. 18-23 ◽  
Author(s):  
J. A. ROBERTSON ◽  
J. K. THOMAS
Keyword(s):  
Storage Time ◽  
Storage Period ◽  
Plate Count ◽  
Enterobacter Agglomerans ◽  
High Moisture ◽  
Plastic Bags ◽  
Plate Counts ◽  
Aerobic Plate Count ◽  
And Storage ◽  
Microbiological Analyses

Samples of freshly dehulled, confectionery sunflower kernels were adjusted to moistures of 5.2, 10.5, and 14.7%, sealed in plastic bags and stored at 35, 75, and 95 F (1.7, 23.9, and 35 C) for 12 weeks. At 2-week intervals aliquots were removed for flavor, chemical, and microbiological analyses. Acid values of oil extracted from stored kernels increased with temperature, moisture content, and storage time. At acid values of 4 or higher, kernels had a sour flavor. In general, the peroxide value decreased with increased moisture at each temperature and storage period. The initial aerobic plate count of the sunflower kernels was log 6.83/g, the Enterobacteriaceae count was log 6.15/g, and the yeast and mold count was log 3.65/g. From countable plates randomly selected, about 80% of the Enterobacteriaceae were identified as Enterobacter agglomerans (Erwinia herbicola). At 35 F microbial counts generally changed little. At 75 F, however, counts decreased rapidly; and at 95 F, yeast and mold counts of 14.7% moisture kernels increased, Enterobacteriaceae counts decreased, and aerobic plate counts decreased except in high moisture samples. A microbiological survey of whole sunflower seed and dehulled kernels from three dehulling operations indicated that contamination of the dehulled kernels was primarily from sunflower hulls rather than from processing equipment.

Enumeration of Enterococci and Aerobic Mesophilic Plate Count in Dried Soup Using Three Reconstitution Methods

1985 ◽  
Vol 48 (9) ◽  
pp. 770-771 ◽  
Author(s):  
WEI-TSYI TING ◽  
GEORGE J. BANWART
Keyword(s):  
Plate Count ◽  
Plate Count Agar ◽  
Plate Counts

A naturally contaminated dried soup sample was reconstituted by three different methods (1:1 swirl, 1:9 soak and 1:9 rapid rehydration) and analyzed for enterococci on m-enterococcus agar and aerobic mesophilic plate count on plate count agar. The enterococcal counts obtained by the 1:1 swirl and the 1:9 soak methods were 41.6% and 26.5%, respectively, higher than that of the commonly used 1:9 rapid rehydration method. The aerobic mesophilic plate counts for the three systems were not significantly different.

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).

Evaluation of a Culture Film (Petrifilm™ YM) Method for Enumerating Yeasts and Molds in Selected Dairy and High-Acid Foods

1990 ◽  
Vol 53 (10) ◽  
pp. 869-874 ◽  
Author(s):  
L. R. BEUCHAT ◽  
B. V. NAIL ◽  
R. E. BRACKETT ◽  
T. L. FOX
Keyword(s):  
Correlation Coefficients ◽  
Food Products ◽  
Cottage Cheese ◽  
Plate Count ◽  
Fungal Cell ◽  
High Acid ◽  
Plate Count Agar ◽  
Sour Cream ◽  
Yeasts And Molds ◽  
Total Yeast

The Petrifilm™ Yeast and Mold (YM) plate was compared to acidified potato dextrose agar (APDA) and chloramphenicol-supplemented plate count agar (CPCA) using pour- and surface-plating techniques for its ability to recover yeasts and molds from hard and soft cheeses, cottage cheese, yogurt, sour cream, fruit juice, salad dressing, relishes, and tomato-based sauces. Correlation coefficients of Petrifilm™ YM plates versus pour-APDA, surface-APDA, pour-CPCA, and surface-CPCA for recovering total yeasts and molds from a composite of the eight test foods were, respectively, 0.993, 0.993, 0.994, and 0.995. Slope and intercept values for populations detected using Petrifilm™ YM plates versus traditional systems ranged, respectively, from 0.984 to 1.008 and −0.051 to 0.149. The coefficient of variation for total yeast and mold populations recovered on Petrifilm™ YM plates was 1.0% compared to 1.2 to 1.7% for traditional enumeration systems. Regardless of the enumeration system employed or the type of fungal cell, i.e., yeast or mold, being enumerated, significantly (P ≤ 0.05) higher populations were generally detected after 5 d compared to 3 d of incubation. After 5 d of incubation, in no case were yeast or total yeast and mold populations detected in the eight food products using Petrifilm™ YM plates significantly lower than respective populations detected using traditional pour- and surface-plating techniques and media. When Petrifilm™ YM plates were used, significantly higher total yeast and mold populations were detected in 3, 1, and 1 out of eight food products compared to using, respectively, pour-APDA, surface-APDA, and surface-CPCA enumeration systems. The Petrifilm™ YM plate offers an acceptable alternative to traditional methods for enumerating yeasts and molds in the dairy and high-acid products evaluated in this study.

scholarly journals Bacteriological and Phytochemical Assessment of Ficus asperifolia Linn. Infusion

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Kolapo Ayoola Fasina ◽  
Titilayo O. Adesetan ◽  
Faithfulness Oseghale ◽  
Haneefat O. Egberongbe ◽  
O. O. Aghughu ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Analytical Techniques ◽  
Plate Count ◽  
Phytochemical Analysis ◽  
Microbiological Analysis ◽  
Determinative Bacteriology ◽  
Biochemical Tests ◽  
Plate Method ◽  
Plate Count Agar ◽  
Yoruba Language

Ficus asperifolia Linn. known as “Eepin” in Yoruba language, or sand paper tree, is a monoecious fig tree whose leaves, bark, seeds, and roots have been used locally in treating many infectious and noninfectious diseases. The study is aimed at investigating the bacteriological and phytochemical potential of Ficus asperifolia Linn. The roots of the plant were harvested and washed, and phytochemical analysis was carried out using standard analytical techniques. Infusion was aseptically prepared, and incubation for 24 hours and microbiological analysis were carried out using the pour plate method on Plate Count Agar (PCA) and Nutrient Agar (NA). Microorganisms were subcultured and identified using morphological and biochemical tests according to “Bergey’s Manual of Determinative Bacteriology.” Phytochemical analysis of the fresh and dry roots revealed the presence of alkaloids, cardenolides, and saponins, while anthraquinones and tannins were absent. Total heterotrophic bacteria count on PCA was 5.6×105 CFU/ml, while on NA, it was 2.3×105 CFU/ml, and four classes of bacteria were isolated including Klebsiella sp., Escherichia coli, Proteus sp., and Bacillus sp. Although the presence of medicinal phytochemicals in F. asperifolia Linn. indicates strong potentials for its use in infusions, the presence of potential pathogens found in the infusions makes it unsafe for consumption.

Fungi in Foods

1975 ◽  
Vol 38 (12) ◽  
pp. 745-746 ◽  
Author(s):  
J. A. KOBURGER ◽  
A. R. NORDEN
Keyword(s):  
Food Samples ◽  
Plate Count ◽  
Most Probable Number ◽  
Probable Number ◽  
Plate Count Agar ◽  
Yeasts And Molds ◽  
Surface Plate

It was possible to compare recovery of yeasts and molds from 30 food samples by three methods, employing plate count agar and broth with added antibiotics. Although the pour plate and surface plate methods gave comparable results, the Most Probable Number (MPN) procedure consistently yielded the highest counts. With some of the samples, the MPN method was the only one in which recovery occurred. It thus appears that this procedure is practical for detection of fungi and may be of use in survey work or when analyzing foods containing low numbers of microorganisms.

Destruction de Microbacterium lacticum, Escherichia coli et Staphylococcus aureus au cours du séchage du lait par atomisation. I. Dénombrement sélectif des bactéries survivantes

1977 ◽  
Vol 23 (6) ◽  
pp. 716-720
Author(s):  
A. Chopin ◽  
G. Mocquot ◽  
Y. Le Graet
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Spray Drying ◽  
Skim Milk ◽  
Resistant Mutant ◽  
Plate Count ◽  
Mannitol Salt Agar ◽  
E Coli ◽  
Plate Count Agar ◽  
Plate Counts

In this paper a method which allows the measure of microbial death rate during spray-drying by means of a streptomycin-resistant mutant that can be grown on a streptomycin-containing agar is described. Plate counts of Microbacterium lacticum, Escherichia coli, and Staphylococcus aureus recovered from skim milk powders were done on plate count agar in the presence and absence of streptomycin and on various selective media. The powders were produced from evaporated milk previously inoculated with those organisms.Our results showed that the proposed method allows the recovery of 78% of M. lacticum, 61% of E. coli, and 100% of S. aureus that survived spray-drying. Recoveries of surviving E. coli on violet bile agar and brilliant green bile 2% were 34% and 29% respectively. Baird-Parker and mannitol salt agar media allow the recovery of all surviving S. aureus, thus showing that S. aureus cells did not lose their ability to grow in media containing 7.5% NaCl. Our results show that physiological injury of the cells during spray-drying differs from injury due to heating only. [Traduit par le journal]

Enumeration of the contaminating bacterial microbiota in unfermented pasteurized milks enriched with probiotic bacteria

2009 ◽  
Vol 55 (4) ◽  
pp. 410-418 ◽  
Author(s):  
C. P. Champagne ◽  
Y. Raymond ◽  
J. Gonthier ◽  
P. Audet
Keyword(s):  
Lactobacillus Rhamnosus ◽  
Microbiological Quality ◽  
Probiotic Bacteria ◽  
Plate Count ◽  
Plate Count Agar ◽  
Bacterial Microbiota ◽  
Standard Plate ◽  
Plate Counts ◽  
Probiotic Lactobacilli ◽  
De Man

Pasteurized and unfermented milks supplemented with probiotic bacteria are appearing on the market. It then becomes a challenge to ascertain the undesirable contamination microbiota in the presence of a largely superior population of probiotic bacteria. A method to enumerate the contaminating microbial microbiota in such probiotic-enriched milks was developed. The probiotic cultures, Lactobacillus rhamnosus Lb-Immuni-T™ and Bifidobacterium animalis subsp. lactis BB-12®, were added to a pasteurized unfermented milk to reach a minimum of 1 billion CFU per 250 mL portion, as ascertained by plating on de Man – Rogosa – Sharpe (MRS) agar in anaerobic conditions. No growth of B. animalis subsp. lactis BB-12 was noted on plate count agar (PCA) or Petrifilm™ plates, and the presence of this culture did not affect standard plate counts (SPC) of contaminating bacteria. However, L. rhamnosus formed colonies on PCA and Petrifilm™ plates. Attempts were thus made to inhibit the growth of the probiotic lactobacilli in PCA. The addition of 2% sodium phosphate (SP) or 5% glycerophosphate (GP) inhibited the growth of the lactobacilli in broths, but pin-point colonies of L. rhamnosus Lb-Immuni-T nevertheless appeared on PCA supplemented with phosphates. SPC could be obtained on PCA + 2% SP by only counting the large colonies, but this resulted in a significant (4.4 fold) underestimation of SPC values. On Petrifilm™ AC, at dilutions 0 to 2, all colonies were considered as being contaminants, while at dilutions 3 and 4, only large colonies were counted for SPC determinations. There was a direct correlation (R2 = 0.99) between SPC values with Petrifilm™ in uninoculated milks and those obtained on probiotic-enriched milks. The high correlation obtained over the 102 to 106 CFU/mL range of SPC values show that this Petrifilm™ method is appropriate to evaluate the microbiological quality of pasteurized milks enriched with L. rhamnosus Lb-Immuni-T and B. animalis subsp. lactis BB-12.

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