scholarly journals Reduction of Microbial Populations on Prunes by Vapor Phase Hydrogen Peroxide

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 815F-815
Author(s):  
Gilbert F. Simmons ◽  
Joseph L. Smilanick ◽  
Shama John ◽  
Dennis A. Margosan
Keyword(s):  
Hydrogen Peroxide ◽  
Vapor Phase ◽  
Culture Medium ◽  
Culture Media ◽  
Microbial Populations ◽  
Plate Count ◽  
Potassium Sorbate ◽  
Plate Count Agar ◽  
Colony Forming Units ◽  
Aerobic Plate Count

Moisture is raised in dehydrated prunes to improve palatability before packaging and potassium sorbate is added to inhibit microbial growth. Vapor phase hydrogen peroxide (VPHP) technology uses hydrogen peroxide pulses to disinfect dried prunes. Dried prunes were obtained from dehydrators. The number of colony-forming units per 10 prunes (cfu/p) was compared between untreated and VPHP treated. Three culture media—dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (PCA), and potato dextrose agar (PDA)—were used to evaluate cfu/p. Similar mean microbe populations were observed on DRBC (67) and PDA (70); PCA had higher cfu/p (99). Microbes washed from untreated prunes obtained from dehydrators were 58 to 112 cfu/p, depending on the culture medium used. The number of cfu/p assessed on all media on VPHP-treated prunes was near 0 after 100 min exposure. Unlike potassium sorbate, hydrogen peroxide is a microbiocide rather than a microbiostat.

scholarly journals 275 VAPOR PHASE HYDROGEN PEROXIDE TREATMENT OF WALNUT NUTMEATS (Juglans regia L.) FOR CONTROL OF MICROORGANISMS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 469d-469
Author(s):  
Gilbert F. Simmons ◽  
Joseph L. Smilanick ◽  
Nuria Denis-Arrue ◽  
Dennis A Margosan ◽  
Shama John
Keyword(s):  
Hydrogen Peroxide ◽  
Vapor Phase ◽  
Culture Media ◽  
Juglans Regia ◽  
Plate Count ◽  
Plate Count Agar ◽  
Hydrogen Peroxide Treatment ◽  
Aseptic Packaging ◽  
Aerobic Plate Count ◽  
Yeasts And Molds

A new vapor phase hydrogen peroxide (VPHP) technology that uses relatively dry hydrogen peroxide pulses is a promising method for the disinfection of surface-borne bacteria, yeasts, and molds on walnut nutmeats. The number of colony forming units per gram (cfu/g) on untreated nutmeats was compared to those VPHP treated. Three culture media; dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (APC, Oxoid), and potato dextrose agar (PDA, Sigma), were utilized to evaluate cfu/g. Similar numbers of cfu/g of product were observed on APC and PDA. The more selective DRBC had lower cfu/g. Microorganisms washed from untreated walnut nutmeats purchased at retail outlets ranged between 17,000-29,000 cfu/g depending upon the culture medium used. The number of cfu/lg on nutmeats after VPHP treatments was reduced to 500-1400, a 95% reduction. VPHP may offer an alternative to propylene oxide fumigation. The moisture content of nutmeats was not significantly altered by VPHP. The Food and Drug Administration lists hydrogen peroxide as a “generally recognized as safe substance” (GRAS). Hydrogen peroxide is already produced in a food grade for aseptic packaging.

Reduction of Microbial Populations on Prunes by Vapor-Phase Hydrogen Peroxide†

1997 ◽  
Vol 60 (2) ◽  
pp. 188-191 ◽  
Author(s):  
GILBERT F. SIMMONS ◽  
JOSEPH L. SMILANICK ◽  
SHAMA JOHN ◽  
DENNIS A. MARGOSAN
Keyword(s):  
Hydrogen Peroxide ◽  
Vapor Phase ◽  
Rose Bengal ◽  
Potato Dextrose Agar ◽  
Microbial Populations ◽  
Plate Count ◽  
Plate Count Agar ◽  
Oxidation Damage ◽  
Aerobic Plate Count ◽  
Treatment Comparisons

Vapor-phase hydrogen peroxide (VPHP) was used to disinfect prunes. Concentrated hydrogen peroxide solution (35%, wt/wt) was volatilized into a stream of dried air to approximately 3.1 mg/l (wt/vol) of hydrogen peroxide. Dried prunes obtained from commercial dehydrators were treated with VPHP and compared to untreated prunes. Microbial populations were determined for treatment comparisons. Untreated dried prune microbial populations were 155, 107, and 111 CFU/g of prunes on aerobic plate count agar, potato dextrose agar, and dichloran rose bengal agar, respectively. In contrast, VPHP-treated prune microbial populations were reduced to near zero on all media after 10 minutes of VPHP exposure. The color of prunes exposed for 20 min or longer, however, showed oxidation damage. No hydrogen peroxide residues were detected 90 days after treatment.

Comparison of a Dry Medium Culture Plate (Petrifilm SM Plates) Method to the Aerobic Plate Count Method for Enumeration of Mesophilic Aerobic Colony-Forming Units in Fresh Ground Beef

1985 ◽  
Vol 48 (12) ◽  
pp. 1044-1045 ◽  
Author(s):  
LORRAINE B. SMITH ◽  
TERRANCE L. FOX ◽  
F. F. BUSTA
Keyword(s):  
Linear Regression Analysis ◽  
Ground Beef ◽  
Microbial Populations ◽  
Plate Count ◽  
Retail Markets ◽  
Count Method ◽  
Colony Forming Units ◽  
Plate Count Method ◽  
Aerobic Plate Count ◽  
Medium Culture

Mesophilic aerobic microbial populations in fresh ground beef were enumerated with a new system, Petrifilm™ SM Plates (PSM), and with the conventional aerobic plate count (APC) method using standard methods agar (SMA). Total colony-forming units were determined in 119 fresh ground beef samples (29 extra-lean, 30 lean and 60 regular) purchased at nine different retail markets over a period of 6 wk. Linear regression analysis of PSM vs. APC counts gave a slope of 0.963, an intercept of −0.027, and a correlation coefficient of 0.951. Mean log10 counts on PSM were 5.86 compared to 6.11 on SMA (P<0.01) or a mean log10 difference of −0.25. These analyses indicate that the Petrifilm SM method would be a possible alternative for the aerobic plate count method.

Study of the Microbial Ecology of Wild and Aquacultured Tunisian Fresh Fish

2011 ◽  
Vol 74 (10) ◽  
pp. 1762-1768 ◽  
Author(s):  
MOUNA BOULARES ◽  
LOBNA MEJRI ◽  
MNASSER HASSOUNA
Keyword(s):  
Aeromonas Hydrophila ◽  
Microbiological Quality ◽  
Common Species ◽  
Microbial Populations ◽  
Plate Count ◽  
Gram Negative Bacteria ◽  
Fresh Fish ◽  
Psychrotrophic Bacteria ◽  
Aerobic Plate Count

Eighty samples of fresh fish were collected in Tunisia and analyzed for microbial load. Quality and hygienic safety of the meat and intestines of wild and aquacultured fresh fish were determined. The mesophilic aerobic plate count and populations of psychrotrophic lactic acid bacteria (LAB) and other psychrotrophic bacteria ranged from 5.67 to 7.29, 4.51 to 6, and 5.07 to 6.21 log CFU/g, respectively. For all microbiological determinations, bacterial counts were lower in meat than in the intestines of fresh fish. For all samples lower microbial populations were found in most of the wild fish than in the aquacultured fish. No isolates of the pathogenic genera Salmonella and Listeria were detected in any sample. Among the 160 strains of biopreservative psychrotrophic LAB and the 150 strains of spoilage psychrotrophic gram-negative bacteria identified by biochemical and molecular methods, Lactobacillus (six species) and Pseudomonas (six species) predominated. Lactococcus, Leuconostoc, Carnobacterium (C. piscicola and C. divergens), Aeromonas, and Photobacterium were the most common genera, and Lactococcus lactis, Lactobacillus plantarum, Pseudomonas fluorescens, and Aeromonas hydrophila were the most common species. These findings indicate that the microbiological quality of fresh fish in Tunisia can be preserved by controlling pathogenic and psychrotrophic bacteria.

Microbiological Status of Fresh Beef Cuts

2006 ◽  
Vol 69 (6) ◽  
pp. 1456-1459 ◽  
Author(s):  
J. D. STOPFORTH ◽  
M. LOPES ◽  
J. E. SHULTZ ◽  
R. R. MIKSCH ◽  
M. SAMADPOUR
Keyword(s):  
Total Coliform ◽  
Incidence Rates ◽  
Microbial Populations ◽  
Plate Count ◽  
Bacterial Populations ◽  
E Coli ◽  
Coliform Count ◽  
Processing Plants ◽  
Aerobic Plate Count ◽  
Whole Muscle

Fresh beef samples (n = 1,022) obtained from two processing plants in the Midwest (July to December 2003) were analyzed for levels of microbial populations (total aerobic plate count, total coliform count, and Escherichia coli count) and for the presence or absence of E. coli O157:H7 and Salmonella. A fresh beef cut sample was a 360-g composite of 6-g portions excised from the surface of 60 individual representative cuts in a production lot. Samples of fresh beef cuts yielded levels of 4.0 to 6.2, 1.1 to 1.8, and 0.8 to 1.0 log CFU/g for total aerobic plate count, total coliform count, and E. coli count, respectively. There did not appear to be substantial differences or obvious trends in bacterial populations on different cuts. These data may be useful in establishing a baseline or a benchmark of microbiological levels of contamination of beef cuts. Mean incidence rates of E. coli O157:H7 and Salmonella on raw beef cuts were 0.3 and 2.2%, respectively. Of the 1,022 samples analyzed, cuts testing positive for E. coli O157:H7 included top sirloin butt (0.9%) and butt, ball tip (2.1%) and for Salmonella included short loins (3.4%), strip loins (9.6%), rib eye roll (0.8%), shoulder clod (3.4%), and clod, top blade (1.8%). These data provide evidence of noticeable incidence of pathogens on whole muscle beef and raise the importance of such contamination on product that may be mechanically tenderized. Levels of total aerobic plate count, total coliform count, and E. coli count did not (P ≥ 0.05) appear to be associated with the presence of E. coli O157:H7 and Salmonella on fresh beef cuts. E. O157:H7 was exclusively isolated from cuts derived from the sirloin area of the carcass. Salmonella was exclusively isolated from cuts derived from the chuck, rib, and loin areas of the carcass. Results of this study suggest that contamination of beef cuts may be influenced by the region of the carcass from which they are derived.

Microbiological Evaluation of Shrimp (Pandalus borealis) Processing

1978 ◽  
Vol 41 (1) ◽  
pp. 40-43 ◽  
Author(s):  
STEPHEN C. RIDLEY ◽  
BOHDAN M. SLABY J
Keyword(s):  
Salt Water ◽  
Bacterial Load ◽  
Microbiological Quality ◽  
Plate Count ◽  
Water Medium ◽  
Pandalus Borealis ◽  
Plate Count Agar ◽  
Cooking Process ◽  
Processing Plants ◽  
Aerobic Plate Count

Line samples from three different shrimp processing plants (brine-cooked shell-on, hand-peeled raw, and machine-peeled cooked) in Maine were examined for microbiological quality. Aerobic plate count (APC) of freshly caught shrimp (Pandalus borealis) was found to be about 530/g (Plate Count Agar at 35 C) while salt-requiring (SR) organisms were at significantly higher concentration (1.11 ×105/g; Salt Water Medium at 21 C). Some increase in psychrotrophic-mesophilic flora of shrimp delivered to the plant was observed. Cooking in-plant or on board the boat drastically reduced the SR flora, which was subsequently observed to increase after culling and inspection in the brine-cooked shell-on process. No such significant fluctuation due to processing was detected in APC. Shrimp sampled from steel barrels before a hand-peeled raw operation exhibited relatively high APC (7.2 × 104/g) and SR microflora (2.78 × 106/g). Heading and hand-peeling reduced the APC and SR bacterial loads by 71 and 95%, respectively. Subsequent processing and holding at room temperature resulted in a product with an APC and SR load of about 4 × 104/g. Similarly, high APC (1.66 × 105/g) and SR bacterial loads (1.84 × 105/g) were detected in samples obtained from a storage hopper of the machine-peeled cooking process. Although significant reduction in bacterial load was detected on line samples of this process (fluming, preheating, and cooking), the total bacterial load reached about 4 × 104/g before the canning step. Low levels of contamination with coliform and/or coagulase-positive staphylococci were detected in the three processes studied.

scholarly journals Application of microbiological method direct epifluorescence filter techique/aerobic plate count agar in the identification of irradiated herbs and spices

2014 ◽  
Vol 3 (3) ◽  
Author(s):  
Maria Concetta Campagna ◽  
Maria Teresa Di Schiavi ◽  
Marina Foti ◽  
Maria Cristina Mosconi ◽  
Giuseppina Mattiolo ◽  
...  
Keyword(s):  
Plate Count ◽  
Microbiological Method ◽  
Plate Count Agar ◽  
Aerobic Plate Count ◽  
Herbs And Spices

Use of Petrifilm™ to Evaluate the Microflora of Frozen Dessert Mixes1

1989 ◽  
Vol 52 (8) ◽  
pp. 549-551 ◽  
Author(s):  
L. B. SMITH ◽  
E. A. ZOTTOLA ◽  
T. L. FOX ◽  
K. CHAUSSE
Keyword(s):  
Linear Relationship ◽  
Raw Milk ◽  
Microbial Populations ◽  
Plate Count ◽  
Standard Methods ◽  
Naturally Occurring ◽  
Colony Forming Units ◽  
Frozen Dessert ◽  
Evaluation Of Data ◽  
Strong Linear Relationship

Ninety vanilla frozen dessert mix samples were analyzed to determine total microbial populations and coliforms present in samples inoculated with a coliform isolated from raw milk. Standard methods agar (SMA, PCA, Difco) and violet red bile agar (VRBA, Difco) as well as Petrifilm™ (PSM, PVRB) were used for plating of samples. Standard VRBA 1:10 method produced significantly higher counts of colony-forming units (CFU) than PVRB 2:3 and VRBA 2:3 methods. VRBA 2:3 colony-forming unit counts were also significantly higher than those on PVRB 2:3, but both methods showed a moderately strong linear relationship. Repeatabilities of all three coliform plating methods (VRBA 1:10, VRBA 2:3, and PVRB 2:3) were acceptably low. Less than 10% of samples plated on SMA and PSM resulted in total aerobic colony-forming units in the countable range, making evaluation of data difficult and resulting in a lack of strong linear relationship between PSM and SMA. An additional 70 local retail store samples containing naturally occurring coliforms were evaluated using PVRB 2:3 and VRBA 1:10 methodology, confirmed in brilliant green lactose bile broth (BGLB, Difco) and compared to standard VRBA 1:10 previously analyzed. All methods were equivalent for mean log coliforms, i.e., 1.38,1.33, and 1.31 for PVRB 2:3, VRBA 2:3, and VRBA 1:10, respectively. Petrifilm™ methods were comparable to standard methods for enumerating coliforms in frozen dairy products, and would be a valid alternative to standard coliform and total plate count methods.

Potassium Sorbate and Recovery of Pectinolytic Psychrotrophs from Vacuum-Packaged Pork

1983 ◽  
Vol 46 (6) ◽  
pp. 499-502 ◽  
Author(s):  
B. R. MYERS ◽  
J. E. EDMONDSON ◽  
M. E. ANDERSON ◽  
R. T. MARSHALL
Keyword(s):  
Klebsiella Oxytoca ◽  
Plate Count ◽  
Most Probable Number ◽  
Potassium Sorbate ◽  
Probable Number ◽  
Public Health Significance ◽  
Colony Forming Units ◽  
Peptone Water ◽  
Health Significance ◽  
Pectinolytic Bacteria

Pork loins were divided into small roasts. Thirty roasts were uninoculated and 30 were inoculated by dipping in 1 % peptone water containing 100 Colony-forming units (CFU)/ml of pectinolytic Yersinia enterocolitica. Twenty-four each of the uninoculated and inoculated roasts were sprayed with or dipped in 5 or 10% solutions of potassium sorbate. All roasts were then vacuum-packaged and stored at 5°C. After storage for 1 or 21 d, three roasts from each group were examined for psychrotrophic plate count (PPC) and the 3-tube most probable number of pectionolytic bacteria. Counts of psychrotrophs on lean surfaces of untreated controls increased by nearly 3.4 log10. Numbers on sorbate-treated lean surfaces increased about 2.0 log10. Growth and differences in counts on fatty surfaces were less. Numbers of pectinolytic bacteria on lean surfaces of controls increased by nearly 2.0 log10, but numbers of pectinase producers did not change significantly during storage of sorbate-treated samples. Of 30 pectinolytic isolates identified from roasts stored 21 d at 5°C, 87% were Yersinia spp. and 13% were Klebsiella oxytoca. Since most of the pectinolytic isolates were psychrotrophs of public health significance, inhibition of their growth by sorbate is of particular importance.

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.

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