Evaluation of Two Standard and Two Chromogenic Selective Media for Optimal Growth and Enumeration of Isolates of 16 Unique Bacillus Species

2017 ◽  
Vol 80 (6) ◽  
pp. 952-962 ◽  
Author(s):  
M. Shahjahan Kabir ◽  
Ying-Hsin Hsieh ◽  
Steven Simpson ◽  
Khalil Kerdahi ◽  
Irshad M. Sulaiman
Keyword(s):  
Food Poisoning ◽  
Optimal Growth ◽  
Egg Yolk ◽  
Growth Conditions ◽  
Bromothymol Blue ◽  
Culture Collection ◽  
Most Probable Number ◽  
Bacillus Species ◽  
Probable Number ◽  
Wide Range

ABSTRACTThe genus Bacillus is a group of gram-positive endospore-forming bacteria that can cause food poisoning and diarrheal illness in humans. A wide range of food products have been linked to foodborne outbreaks associated with these opportunistic pathogens. The U.S. Food and Drug Administration recommends (in their Bacteriological Analytical Manual) the use of Bacara or mannitol egg yolk polymyxin (MYP) agar plates and the most-probable-number (MPN) method for enumeration and confirmation of Bacillus cereus and related species isolated from foods, sporadic cases, outbreaks, and routine environmental surveillance samples. We performed a comparative analysis of two chromogenic media (Bacara and Brilliance) and two traditional media (MYP and polymyxin egg yolk mannitol bromothymol blue agar [PEMBA]) for the isolation and enumeration of 16 Bacillus species under modified growth conditions that included pH, temperature, and dilution factor. A total of 50 environmental, food, and American Type Culture Collection reference isolates from 16 distinct Bacillus species were evaluated. A food adulteration experiment also was carried out by artificially adulterating two baby food matrices with two isolates each of B. cereus and Bacillus thuringiensis. Our results clearly indicated that chromogenic plating media (Bacara and Brilliance) are better than conventional standard media (MYP and PEMBA) for the detection and enumeration of B. cereus in foods and other official regulatory samples. The comparison of the two chromogenic media also indicated that Brilliance medium to be more efficient and selective for the isolation of Bacillus.

Optimization of Growth Conditions of Citrus Anthracnose Agent Colletotrichum gloeosporioides Isolates in Tunisia

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Ben Hadj-Daoud H ◽  
◽  
Ben Salem I ◽  
Boughalleb-M’Hamdi N ◽  
◽  
...  
Keyword(s):  
Morphological Traits ◽  
Laboratory Experiments ◽  
Plant Pathogens ◽  
Colletotrichum Gloeosporioides ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Fruit Drop ◽  
Nutritional Conditions ◽  
Solid Media ◽  
Wide Range

Background: Colletotrichum gloeosporioides is important plant pathogens on a wide range of plant hosts such as citrus causing pre- or post-harvest infections as anthracnose, post-bloom fruit drop, tearstain and stem-end rot on fruit, or wither-tip of twigs. Method: The optimization of growth conditions of this pathogen was performed (solid media, temperature, pH and water potential under laboratory experiments). Results: Our results revealed that the maximum radial growth of C. gloeosporioides was recorded on SDA medium. All isolates were able to grow on PDA at temperatures of 15 and 30°C (over 0.7cm/day). Optimal growth radial was recorded at pH 5, 6, 7 and 8. Similar responses were obtained with both salt types, but, in general, C. gloeosporioides was more tolerant to KCl than NaCl. Conclusion: Studies of cultural, morphological traits of the pathogen are prominent to understand the response of the pathogen in different environmental and nutritional conditions.

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.

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.

A Nucleation Study of GaN Multifunctional Nanostructures

2004 ◽  
Vol 831 ◽  
Author(s):  
Gupta Shalini ◽  
Kang Hun ◽  
Strassburg Martin ◽  
Asghar Ali ◽  
Senawiratne Jayantha ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Mocvd Growth ◽  
Aspect Ratios ◽  
Nucleation Sites ◽  
Wide Range ◽  
Metal Organic ◽  
Multifunctional Nanostructures

ABSTRACTThis paper reports the Metal Organic Chemical Vapor Deposition (MOCVD) growth of GaN nanostructures. The use of MOCVD allows the direct integration of these nanostructures into pre-existing device technology. The formation of GaN nanostructures grown on AlN epitaxial layers were studied as a function of growth temperature, growth rate, V-III ratio and the amount of deposited material. A wide range of temperatures from 800 °C to 1100 °C and V-III ratios from 30 to 3500 were applied to determine the optimal growth conditions for nucleation studies in a modified production reactor. Small GaN nanostructures with lateral dimensions below 50 nm and low aspect ratios were obtained using relatively low temperatures of 815 °C and extreme metal-rich growth conditions. Island densities up to 1010 cm−2 were achieved using silane as an anti-surfactant to increase the available nucleation sites. Manganese has been incorporated into these nanostructures to enhance the multifunctional ferromagnetic properties of GaMnN.

Uptake and Elimination of Bacteria in Shellfish*

1980 ◽  
Vol 43 (2) ◽  
pp. 124-126 ◽  
Author(s):  
FRANK O. PERKINS ◽  
DEXTER S. HAVEN ◽  
REINALDO MORALES-ALAMO ◽  
MARTHA W. RHODES
Keyword(s):  
Crassostrea Virginica ◽  
Environmental Conditions ◽  
Fecal Coliform ◽  
Sea Water ◽  
Fecal Coliforms ◽  
Most Probable Number ◽  
Probable Number ◽  
General Review ◽  
Wide Range ◽  
Bacterial Accumulation

A general review of knowledge concerning bacterial accumulation and depletion by commercially significant bivalve molluses is presented. Naturally contaminated shellfish can eliminate fecal coliforms (FC) in 48 h to levels below most market standards over a wide range of environmental conditions when sea water flowing to the molluses is treated so that fecal coliform levels are indeterminate or marginally determinate as assayed by standard methodology. Most probable number (MPN) enumerations of shellfish depurated for 48 h by the authors yielded a median value of &lt; 18 FC/100 g of oyster (Crassostrea Virginica) meats with &lt; 10% of the samples exceeding 78 FC/100 g.

Comparison of the SimPlate™ Total Plate Count Method with Petrifilm™, Redigel™, and Conventional Pour-Plate Methods for Enumerating Aerobic Microorganisms in Foods

1998 ◽  
Vol 61 (1) ◽  
pp. 14-18 ◽  
Author(s):  
L. R. BEUCHAT ◽  
F. COPELAND ◽  
M. S. CURIALE ◽  
T. DANISAVICH ◽  
V. GANGAR ◽  
...  
Keyword(s):  
Food Samples ◽  
Test Methods ◽  
Plate Count ◽  
Most Probable Number ◽  
Suitable Alternative ◽  
Probable Number ◽  
Plate Count Agar ◽  
Total Plate Count ◽  
Wide Range ◽  
Highly Correlated

The SimPlate™ Total Plate Count (TPC) method, developed by IDEXX Laboratories, Inc., is designed to determine the most probable number of aerobic microorganisms in foods. The 24-h test was compared to the conventional plate count agar (PCA) method, the Petrifilm™ Aerobic Count plates, and the Redigel™ Total Count procedure for enumerating microflora in 751 food samples. Results using the SimPlate™ TPC method were highly correlated (r ≥ 0.96) with results from other test methods. Slopes (0.96–0.97) were not significantly different from 1, and y intercepts (−0.03–0.08) were not different from 0. The SimPlate™ has a high counting range (&gt; 1600 most probable number per single dilution), thus requiring fewer dilutions of samples compared to other methods evaluated. Some foods, e.g., raw liver, wheat flour, and nuts, contain enzymes that gave false-positive reactions on SimPlates™. Overall, however, the SimPlate™ TPC method is a suitable alternative to conventional PCA, Petrifilm™, and Redigel™ methods for estimating populations of mesophilic aerobic microorganisms in a wide range of foods.

Inactivation of Mycobacterium avium subsp. paratuberculosis during Cooking of Hamburger Patties

2013 ◽  
Vol 76 (7) ◽  
pp. 1194-1201 ◽  
Author(s):  
PHILIPP HAMMER ◽  
HANS-GEORG C. WALTE ◽  
SÖ NKE MATZEN ◽  
JANN HENSEL ◽  
CHRISTIAN KIESNER
Keyword(s):  
Mycobacterium Avium ◽  
Egg Yolk ◽  
Mycobacterium Avium Subsp ◽  
Most Probable Number ◽  
Heat Inactivation ◽  
Inactivation Kinetics ◽  
Bacterial Reduction ◽  
Probable Number ◽  
Mycobacterium Avium Subsp Paratuberculosis ◽  
Cooking Times

The role of Mycobacterium avium subsp. paratuberculosis (MAP) in Crohn's disease in humans has been debated for many years. Milk and milk products have been suggested as possible vectors for transmission since the beginning of this debate, whereas recent publications show that slaughtered cattle and their carcasses, meat, and organs can also serve as reservoirs for MAP transmission. The objective of this study was to generate heat-inactivation data for MAP during the cooking of hamburger patties. Hamburger patties of lean ground beef weighing 70 and 50 g were cooked for 6, 5, 4, 3, and 2 min, which were sterilized by irradiation and spiked with three different MAP strains at levels between 102 and 106 CFU/ml. Single-sided cooking with one flip was applied, and the temperatures within the patties were recorded by seven thermocouples. Counting of the surviving bacteria was performed by direct plating onto Herrold's egg yolk medium and a three-vial most-probable-number method by using modified Dubos medium. There was considerable variability in temperature throughout the patties during frying. In addition, the log reduction in MAP numbers showed strong variations. In patties weighing 70 g, considerable bacterial reduction of 4 log or larger could only be achieved after 6 min of cooking. For all other cooking times, the bacterial reduction was less than 2 log. Patties weighing 50 g showed a 5-log or larger reduction after cooking times of 5 and 6 min. To determine the inactivation kinetics, a log-linear regression model was used, showing a constant decrease of MAP numbers over cooking time.

scholarly journals Detection and quantification of Salmonella in fresh vegetables in Perak, Malaysia

Food Research ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 441-448 ◽  
Author(s):  
Seow Hoon Saw ◽  
J.L. Mak ◽  
M.H. Tan ◽  
S.T. Teo ◽  
T.Y. Tan ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Food Poisoning ◽  
Leafy Vegetables ◽  
Most Probable Number ◽  
Salmonella Spp ◽  
Probable Number ◽  
Increased Risk ◽  
Fresh Vegetables ◽  
Serovar Typhimurium ◽  
Wet Market

The eating of fresh and minimally processed vegetables is getting popular among Malaysians. This trend poses an increased risk of food poisoning associated with the consumption of fresh produce contaminated with pathogenic bacteria. Salmonellosis is a foodborne disease caused by several non-typhoidal Salmonella enterica serovars, predominantly serovars Enteritidis and Typhimurium. The present study aimed to determine the prevalence of Salmonella spp., S. enterica serovar Enteritidis and S. enterica serovar Typhimurium in fresh leafy vegetables such as cabbages (n = 40), lettuces (n = 20), and fruit vegetables such as tomatoes (n = 40), carrots (n = 40) and cucumbers (n = 40), which were sold by three different hypermarkets and a wet market in Kampar, Perak, Malaysia. The study was performed over a period of 13 months (January 2018 to January 2019). A combination of most probable number-multiplex polymerase chain reaction (MPN-mPCR) method was used to quantify the concentrations of Salmonella spp., S. enterica serovar Enteritidis and S. enterica serovar Typhimurium in the examined samples. The results of this study demonstrated that of the vegetables tested, tomatoes, carrots and lettuces were not contaminated by Salmonella spp., S. enterica serovar Enteritidis and S. enterica serovar Typhimurium. However, the presence of Salmonella spp. was detected in 3.3% of cabbages from the hypermarket, with estimated microbial loads ranging from <3.0 MPN/g to 15.0 MPN/g. On the other hand, S. enterica serovar Typhimurium was detected in 10.0% of the cucumbers from hypermarkets and 20% of them from the wet market. Their microbial loads were ranging from <3.0 MPN/g to >1,100 MPN/g. This indicated that cabbages and cucumbers could be the potential sources of salmonellosis. Therefore, the monitoring of food safety and hygienic practices should be strictly enforced by relevant government agencies to avoid potential poisoning by foodborne pathogens.

scholarly journals Identification and enumeration of microbial organisms in grey water in the Khayelitsha informal settlement, Western Cape, South Africa

2020 ◽  
Vol 20 (3) ◽  
pp. 1114-1126
Author(s):  
Qenehelo A. Leuta ◽  
James P. Odendaal ◽  
Arnelia N. Paulse
Keyword(s):  
Escherichia Coli ◽  
Informal Settlement ◽  
Most Probable Number ◽  
Bacillus Species ◽  
Western Cape ◽  
Gram Positive ◽  
Klebsiella Species ◽  
Grey Water ◽  
Probable Number ◽  
Common Misconception

Abstract Grey water, as opposed to blackwater, is generally assumed to be a safer and more acceptable wastewater source that could be considered for reuse. This is mainly due to a common misconception that its microbial load is lower compared to that of blackwater (domestic sewage). This study aimed to determine the presence of microbial contaminants, specifically pathogens, in stagnant grey water in the RR Section in Khayelitsha, Western Cape. The most probable number (MPN) technique was conducted to determine faecal coliform (FC) and Escherichia coli (EC) counts in the samples. The API 20E and the RapID ONE systems were used to identify possible pathogenic Gram-negative microorganisms, while the isolated Gram-positive microorganisms were identified using the BBL Crystal Gram-Positive (GP) Identification (ID) system. The highest respective FC and EC counts observed during this period were recorded as 2.8 × 107 microorganisms/100 mL (Site F, week 5). The RapID ONE and the API 20 identification systems identified mostly Escherichia coli, Klebsiella species and Enterobacter cloacae, amongst others, while the BBL Crystal-GP ID system identified mostly Corynebacterium and Bacillus species. The presence of these organisms raises health concerns for the community of RR Section.

Recovery of Salmonella from Shell Eggs

1991 ◽  
Vol 74 (5) ◽  
pp. 821-826
Author(s):  
Patricia Stephenson ◽  
Felicia B Satchell ◽  
Geraldine Allen ◽  
Wallace H Andrews
Keyword(s):  
Brain Heart Infusion ◽  
Egg Yolk ◽  
Most Probable Number ◽  
Probable Number ◽  
Selective Enrichment ◽  
Shell Eggs ◽  
Peptone Water ◽  
Egg Albumen ◽  
Liquid Whole Egg ◽  
Whole Egg

Abstract A preenrlchment procedure and a direct selective enrichment procedure were compared for recovery of Salmonella artificially inoculated into liquid whole egg, egg yolk, and egg albumen. For liquid whole egg and egg yolk, the 2 procedures were comparable. With egg albumen, however, preenrlchment In lactose broth gave significantly higher recoveries than did direct selective enrichment in either selenite cystine or tetrathionate broths. The lactose preenrlchment procedure was used to determine the survival of S. enterltldla in egg yolk and egg albumen over a period of 7 days. As shown by most probable number determinations, counts of S. enterltldla Inoculated Into egg albumen decreased by 3 log units, whereas those in egg yolk did not change significantly. It is recommended, therefore, that only the egg yolk be examined for this pathogen. In a comparison of 5 different preenrlchment media (lactose broth, brain heart Infusion broth, trypticase soy broth, buffered peptone water, and nutrient broth), lactose broth was somewhat less productive than the other 4 media for the recovery of Salmonella from egg yolks. Trypticase soy broth gave the highest recovery.

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