Use of Iron Milk Medium for Enumeration of Clostridium perfringens

1982 ◽  
Vol 65 (5) ◽  
pp. 1129-1133 ◽  
Author(s):  
William D St John ◽  
Jack R Matches ◽  
Marleen M Wekell
Keyword(s):  
Clostridium Perfringens ◽  
Incubation Time ◽  
Incubation Temperature ◽  
Egg Yolk ◽  
Most Probable Number ◽  
Biochemical Tests ◽  
Probable Number ◽  
Large Numbers ◽  
Whole Milk ◽  
Short Incubation Time

Abstract A simple iron milk medium was used for isolation and enumeration of Clostridium perfringens from soil, sludge, and water samples. The whole milk contained only iron powder as a reducing agent; no other inhibitors were added. The iron milk most probable number (MPN) procedure was compared with 4 plating media: sulfite-polymyxin-sulfadiazine, Shahidi-Ferguson perfringens, tryptose-sulfite- cycloserine (both with and without egg yolk), and tryptone-sulfite-neomycin. The selectivity of the iron milk relies solely on the rapid growth of C. perfringens at 45°C and the stormy fermentation reaction within 18 h. Isolates were confirmed as C. perfringens by standard biochemical tests. The iron milk MPN procedure compared very well with the 4 plating media tested. Selectivity of incubation temperature, short incubation time, and ease of identification by the characteristic stormy fermentation make this method ideal for enumerating C. perfringens from large numbers of samples.

Levels and Enterotoxigenicity of Clostridium perfringens in Pozole, Tamales, and Birria

2005 ◽  
Vol 68 (2) ◽  
pp. 331-335 ◽  
Author(s):  
V. NAVARRO-HIDALGO ◽  
E. CABRERA-DÍAZ ◽  
H. ZEPEDA ◽  
L. MOTA DE LA GARZA ◽  
A. CASTILLO ◽  
...  
Keyword(s):  
Clostridium Perfringens ◽  
Cell Elongation ◽  
Cytotoxic Effect ◽  
Cell Lysis ◽  
Vero Cells ◽  
Plate Count ◽  
Most Probable Number ◽  
Probable Number ◽  
Quantitative Survey ◽  
Plate Counts

A quantitative survey of Clostridium perfringens in typical foods served at local restaurants was conducted for 18 months in Guadalajara, Mexico. A total of 151 samples, including goat's birria (50), pozole (50), and beef tamales (51), were collected from small restaurants in Guadalajara. Samples were tested for C. perfringens by the most probable number (MPN) method and for mesophilic aerobic plate counts (MAPCs) and coliform, yeast, and mold counts by plate count methods. Isolates confirmed as C. perfringens were further sporulated and tested for cytotoxic or cytotonic effect against Vero cells as an indication of enterotoxin production. C. perfringens was detected in 78 (52%) of all samples at concentrations that ranged from 2.3 to 5.4 log MPN/g. Average MAPCs were 1.3 to 2.7 log CFU/g, depending on the type of dish. Coliform counts ranged from less than 1.0 to 1.5 CFU/g, and yeast and mold counts were less than 1.0 log CFU/g in all cases. A total of 118 isolates of C. perfringens were tested for enterotoxic effect on Vero cells; 82 (70%) showed activity against Vero cells. Of them, 31 isolates induced cell lysis, indicating cytotoxic effect; 41 induced cell elongation, indicating cytotonic effect; and 10 produced both cytotoxic and cytotonic effect. Dilution of the bacterial filtrates that were still producing an effect on Vero cells ranged from 1:80 to 1:5,120. These results underscore the importance of determining enterotoxigenicity when testing for C. perfringens in foods.

Survival of Borrelia burgdorferi in Whole Milk, Low Fat Milk, and Skim Milk at 34°C and in Skim Milk at 5°C

1991 ◽  
Vol 54 (7) ◽  
pp. 532-536 ◽  
Author(s):  
GERALDINE M. FARRELL ◽  
AHMED E. YOUSEF ◽  
ELMER H. MARTH
Keyword(s):  
Borrelia Burgdorferi ◽  
Milk Protein ◽  
Skim Milk ◽  
Storage Period ◽  
Most Probable Number ◽  
Low Fat ◽  
Probable Number ◽  
Whole Milk ◽  
The Mean ◽  
D Values

Autoclaved whole milk, low-fat milk, protein-fortified skim milk and regular skim milk were inoculated to contain ca. 105 to 106 Borrelia burgdorferi strains 35210, 35211, or EBNI/ml and stored at 34°C for 16 d. Similarly inoculated skim milk also was held at 5°C for 46 d. Numbers of survivors were estimated by the Most Probable Number (MPN) technique. In all instances, numbers of B. burgdorferi decreased over the storage period. At 34°C, no strain of B. burgdorferi was detected after day 12. The mean D-values, at 34°C, for strains 35210, 35211, and EBNI were 2.2, 2.4, and 2.2 d, respectively. The mean D-values, at 34°C, for all strains in whole milk, low-fat milk, protein-fortified skim milk, and regular skim milk were 2.4, 2.3, 1.9, and 2.4 d, respectively. At 5°C, spirochete numbers in regular skim milk decreased, but all three strains remained at a detectable level for 46 d. The mean D-values, at 5°C, for strains 35210, 35211, and EBNI were 12, 15, and 12 d, respectively.

scholarly journals Isolation and Enumeration of Escherichia coli from Soil and Water

2020 ◽  
Vol 36 (2) ◽  
pp. 75-77
Author(s):  
Anindita Bhowmik ◽  
Sunjukta Ahsan
Keyword(s):  
Escherichia Coli ◽  
Water Samples ◽  
Gas Production ◽  
Soil Samples ◽  
Most Probable Number ◽  
Biochemical Tests ◽  
Probable Number ◽  
E Coli ◽  
Dilution Series

Majority of the population of Bangladesh depend on tap or surface water as their source of water supply. This study was carried out to examine the microbial quality of both water and soil collected from different places using the multiple tube fermentation technique to determine coliform count by the most probable number (MPN) method in brilliant green lactose broth (BGLB) media.Inoculum from positive tubes of the presumptive test were further transferred on eosinemethylene blue (EMB) and MacConkey agar.The organisms isolated were further characterized using biochemical tests. Out of 93 water samples, 30 (32.26%) indicated the presence of lactose fermenter and gas producer in all 3 tubes of dilution series using inoculum quantities of 1.0, 0.1 and 0.01 ml, whereas out of 85 soil samples, 45 (52.94%) showed acid and gas production in all 3 tubes of dilution series.Among 85 soil samples, 40 samples that contained at least one positive in each dilution series and among 93 water samples, 31 samples that contained at least one positive in each dilution series were further re-identified with biochemical tests.This study showed 30.59% soil isolates and 26.88% water isolates were Escherichia coli which highlighted the fact that both water and soil act as a major reservoir of E.coli, which indicates possible fecal contamination as well as presence of potentially pathogenic E. coli. Bangladesh J Microbiol, Volume 36 Number 2 December 2019, pp 75-77

Differentiation of Clostridium perfringens from Related Clostridia in Iron Milk Medium

1985 ◽  
Vol 48 (2) ◽  
pp. 130-134 ◽  
Author(s):  
CARLOS ABEYTA ◽  
ANITA MICHALOVSKIS ◽  
MARLEEN M. WEKELL
Keyword(s):  
Clostridium Perfringens ◽  
High Selectivity ◽  
Positive Response ◽  
Food Samples ◽  
Gas Production ◽  
The Other ◽  
Plate Count ◽  
Most Probable Number ◽  
Probable Number ◽  
Positive Results

The stormy fermentation reaction of Clostridium perfringens in iron milk medium was compared to that of several C. perfringens-like strains. These clostridia, C. barati, C. perenne, C. absonum, and C. paraperfringens are very similar to C. perfringens on the basis of certain biochemical reactions and, consequently, are often difficult to distinguish from C. perfringens. Furthermore, these related clostridia may also be present in foods. Results of this study demonstrate that after 18 h of incubation at 45°C, only C. perfringens gave a positive reaction in iron milk with inocula as low as 22 cells/g. Some of the other strains began to show only gas production at 18 h. After 24 to 42 h some strains gave positive results and after 72 h all were positive. Enumeration of C. perfringens from food samples in iron milk medium by a 3-tube most probable number (MPN) technique gave similar results to enumeration by plate count using Shahidi-Ferguson Perfringens (SFP) agar. Furthermore, a rapid positive response occurred after only 2 and 3 h incubation of iron milk inoculated with 108 and 107 cells/ml, respectively. The high selectivity, ease of identification and rapid growth of C. perfringens in iron milk make the iron milk MPN procedure a valuable assay for accurate enumeration and differentiation of C. perfringens from related Clostridia in food products.

Extended Incubation of LST and BGB Tubes and the MPN Estimates of Coliforms

1994 ◽  
Vol 57 (8) ◽  
pp. 740-742 ◽  
Author(s):  
LAWRENCE A. ROTH ◽  
HAROLD BENGSCH ◽  
CHARLES DAVIDSON ◽  
JAMES S. DICKSON
Keyword(s):  
Incubation Time ◽  
Brilliant Green ◽  
Regulatory Compliance ◽  
Most Probable Number ◽  
Lauryl Sulfate ◽  
Interlaboratory Comparisons ◽  
Confidence Limits ◽  
Probable Number

Extending the incubation time past the standard 48 h for presumptive lauryl sulfate tryptose (LST) broth and confirmed brilliant green bile (BGB) broth tests for coliforms resulted in increases in most probable number (MPN) estimates. Whereas 40% of the samples showed an increase in the presumptive MPN when the incubation was extended from 48 to 72 h, only 5% showed confirmed MPNs, which exceeded the 95% confidence limits established for the 48-h confirmed MPNs. Extending the incubation of BGB tubes to 72 h resulted in less than 5% of the samples exhibiting increased MPNs, which exceeded the 48-h 95% confidence limits. Some loss in viability of coliforms was observed when LST tubes were incubated beyond 72 h. The study demonstrates the importance of adhering to standard incubation times for interlaboratory comparisons and ensuring regulatory compliance.

Bacterial Populations of Ground Beef, Textured Soy Protein and Ground Beef Extended With Soy Protein After 3 and 10 Days of Refrigerated Storage1,2

1978 ◽  
Vol 41 (8) ◽  
pp. 647-653 ◽  
Author(s):  
JAMES F. FOSTER ◽  
RICHARD C. HUNDERFUND ◽  
JAMES L. FOWLER ◽  
JOHN T. FRUIN ◽  
LINDA S. GUTHERTZ
Keyword(s):  
Soy Protein ◽  
Ground Beef ◽  
Microbial Populations ◽  
Plate Count ◽  
Most Probable Number ◽  
Bacterial Populations ◽  
Probable Number ◽  
Fecal Streptococcus ◽  
Large Numbers ◽  
Aerobic Plate Count

A survey of the microbial populations of 31 samples of ground beef (GB), textured soy protein (TSP), and ground beef extended with TSP (SGB) after 3 and 10 days of storage at 4 C was done. Analyses included aerobic plate count (APC), psychrotrophic plate count (PPC), coliform Most Probable Number (CMPN) and plate determinations (CPC), Escherichia coli MPN (EMPN) and plate determinations (EPC), Staphylococcus aureus MPN, and fecal streptococcus plate count. Statistical analyses of data from the enumeration procedures showed significant increases in the total microbial flora after 10 days of storage. PPCs were significantly higher than APCs. CMPNs were significantly higher than CPCs for GB and SGB. The EMPNs were significantly higher than EPCs in SGB only. These products contained a variety of microorganisms many in large numbers; however if properly handled and cooked before consumption, these products should present no public health problems.

scholarly journals Comparison of media and methods for countingClostridium perfringensin poultry meat and further-processed products

1980 ◽  
Vol 84 (1) ◽  
pp. 151-158 ◽  
Author(s):  
B. W. Adams ◽  
G. C. Mead
Keyword(s):  
Egg Yolk ◽  
Poultry Meat ◽  
Most Probable Number ◽  
Similar Species ◽  
Good Growth ◽  
Probable Number ◽  
Direct Plating ◽  
Confirmatory Tests ◽  
Processed Products ◽  
Reference Strains

SUMMARYA Most Probable Number (MPN) method involving Differential Reinforced Clostridial Medium followed by streaking on Willis & Hobbs medium was com pared with direct plating of samples on Tryptose-Suiphite-Cycloserine agar with out egg yolk, and two forms of Oleandomycin-Polymyxin-Suiphadiazine-Per fringens agar, one being prepared from a commercial, dehydrated product.With skin samples taken from chicken carcasses at different stages of processing, the three direct plating media gave similar counts ofCl. perfringenswhereas results obtained with the MPN method were consistently lower.Although counts ofCl. perfringensfrom various further processed products were usually < 10/g, the three plating media showed similar specificity for this organism.All media supported good growth of reference strains ofClostridium perfringensbut it was founsi that physiologically similar species, includingCl. absonum, Cl. paraperfringens and Cl. perenne alsogrew uninhibited in these media and produced colonies identical with those ofCl. perfringens, thus indicating the need for confirmatory tests forCl. perfringenswhen examining natural samples.

Conjugated Linoleic Acid Production by Fermentation

2006 ◽  
Vol 2 (4) ◽  
Author(s):  
Ming Dong ◽  
Shuting Qi
Keyword(s):  
Linoleic Acid ◽  
Incubation Time ◽  
Lactobacillus Acidophilus ◽  
Seed Oil ◽  
Incubation Temperature ◽  
Conversion Ratio ◽  
Isomerase Activity ◽  
Whole Milk ◽  
Alfalfa Seed ◽  
Linoleic Acid Isomerase

Lactobacillus acidophilus 1.1854 was used for CLA production in whole milk and alfalfa seed oil was used as substrate. Alfalfa seed oil contained linoleic acid about 40%. Results showed that alfalfa seed oil addition to the culture improved CLA production, indicating the presence of linoleic acid isomerase activity in the culture. The concentration of lactic acid bacteria, the incubation time, the substrate concentration, the pH, incubation temperature, the pre-incubation time and the substrate amount of pre-incubation were studied in our research and they are optimized at 2.5%(v/v), 21h, 0.05%(v/v), pH 6.4, 37°C, 11h and 10µL which brought the optimal conversion ratio at about 50%.

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