Destruction of Salmonella Species Heated in Aqueous Salt Solutions by Microwave Energy

1993 ◽  
Vol 56 (9) ◽  
pp. 763-768 ◽  
Author(s):  
RONALD A. HEDDLESON ◽  
STEPHANIE DOORES ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
GERALD D. KUHN
Keyword(s):  
Phosphate Buffer ◽  
Microwave Energy ◽  
Constant Time ◽  
Salmonella Spp ◽  
Final Temperature ◽  
Minimum Concentration ◽  
Mixed Mean ◽  
Buffer Control ◽  
Microbial Destruction ◽  
Saline Solutions

Concentrations of 0.1, 0.5, 0.75, 1.0, and 1.25% wt/vol (0.017, 0.085, 0.13, 0.17, and 0.21 M, respectively) sodium chloride were added to 0.3 mM phosphate buffer, pH 6.8, and heated by microwave energy to study the relationship between salt concentration, temperatures achieved, and microbial destruction. Heating Salmonella spp. in saline solutions for a constant time (45 s) or to a constant final temperature (60°C) was also investigated. Fiberoptic thermometry was employed to obtain a temperature profile at specific sites within the solution. When heating for a constant time period, a minimum concentration of 0.75% wt/vol NaCl was necessary to afford Salmonella spp. significantly (P = 0.05) greater protection than the phosphate buffer control. Sodium, potassium, magnesium, and calcium chloride (1.0% wt/vol) in 0.3 mM phosphate buffer were also inoculated with a mixture of Salmonella spp. and heated by microwave energy. Of the salts examined, solutions containing NaCl consistently achieved the highest final surface temperature and largest temperature gradient from the surface to the bottom of the container. The amount of destruction of Salmonella spp. heated to a mixed mean final temperature of 60°C in buffer containing 1.0% wt/vol concentrations of NaCl, KCl, CaCl2, and MgCl2 was 56.4, 71.2, 72.8, and 88.7%, respectively. No relationship was found between the valency of the cation used and final temperatures achieved.

Survival of Salmonella Species Heated by Microwave Energy in a Liquid Menstruum Containing Food Components

1991 ◽  
Vol 54 (8) ◽  
pp. 637-642 ◽  
Author(s):  
RONALD A. HEDDLESON ◽  
STEPHANIE DOORES ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
GERALD D. KUHN ◽  
MORRIS G. MAST
Keyword(s):  
Protective Effect ◽  
Phosphate Buffer ◽  
Corn Oil ◽  
Microwave Energy ◽  
Depth Of Penetration ◽  
Salmonella Spp ◽  
Final Temperature ◽  
Mercury Thermometer ◽  
The Mean ◽  
Buffer Control

Common food constituents were examined to determine the protective influence they may exert on a mixture of Salmonella species heated by microwave energy. A model system was developed, wherein combinations of sucrose, sodium chloride, caseinate and corn oil, all at 1.0% (w/v) concentrations, were added to 0.3 mM phosphate buffer (pH 6.8), producing a total volume of 100 ml. Salmonella-inoculated solutions were heated for 47 sec in a 700 watt microwave oven. Temperatures at localized areas were monitored by fluorescent fiberoptic (fluoroptic) thermometry as the solutions heated, and by mercury thermometer after heating. The mean final temperature achieved for the various combinations of solutes was not significantly different and varied only by 4°C as measured by a mercury thermometer. However, solutions containing NaCl afforded the Salmonella spp. up to 170 times the protection of the phosphate buffer control. This protective effect occurred although the mean final temperature of NaCl-containing solutions would be as high as those solutions lacking salt. Fluoroptic thermometry temperature profiles revealed that surface temperatures were higher when NaCl was present in solution, due to decreased depth of penetration of the microwaves. This re-sulted in decreased temperatures at greater depths. Of the solutes evaluated, only NaCl appears to confer a significant protective effect.

Viability Loss of Salmonella Species, Staphylococcus aureus, and Listeria monocytogenes in Complex Foods Heated by Microwave Energy

1996 ◽  
Vol 59 (8) ◽  
pp. 813-818 ◽  
Author(s):  
RONALD A. HEDDLESON ◽  
STEPHANIE DOORES ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
GERALD D. KUHN
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Chemical Composition ◽  
Food Systems ◽  
Sodium Content ◽  
Salmonella Spp ◽  
Uht Milk ◽  
Mixed Mean ◽  
Liquid Whole Egg ◽  
And Staphylococcus Aureus

The chemical composition of five foods (UHT milk, beef broth, pudding, cream sauce, and liquid whole egg) was examined to determine factors important in achieving uniform temperatures within foods heated in a 700 W microwave oven. Proximate analyses were performed on all food systems to relate their chemical composition to temperatures and to destruction of microwave-heated Salmonella species, Listeria monocytogenes Scott A and V7 and Staphylococcus aureus ATCC 25923. Microwave heating times were chosen such that the final mixed mean temperature achieved by systems was 60°C for Salmonella spp. and L. monocytogenes, and 65°C for S. aureus. The amount of destruction of Salmonella spp. varied from 3.17 log CFU/ml in UHT milk to 0.44 log CFU/ml in beef broth. L. monocytogenes strains incurred the greatest amount of destruction in pudding (2.39 log CFU/g), while the least amount of destruction was observed in cream sauce (1.63 log CFU/ml). There were no significant differences in the amount of destruction of S. aureus heated in the five foods. The pH and aw of these foods did not affect survival of thermally stressed Salmonella, L. monocytogenes, or S. aureus cells. Of the food components examined, sodium content was the primary influence on the uniformity of temperatures achieved within foods, and, in turn, on the survival of bacteria.

scholarly journals First Report of Bacterial Blight of Crucifers Caused by Pseudomonas cannabina pv. alisalensis in Australia

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 1027-1027 ◽  
Author(s):  
C. T. Bull ◽  
I. Rubio
Keyword(s):  
Pseudomonas Syringae ◽  
Phosphate Buffer ◽  
Bacterial Blight ◽  
Control Treatment ◽  
Wagga Wagga ◽  
Bacterial Disease ◽  
Banding Patterns ◽  
First Report ◽  
Dna Fragment ◽  
Buffer Control

In 1978 and 1979, Pseudomonas syringae pv. maculicola strains DAR 33362, DAR 33363, and DAR 33406 were isolated from diseased Brassica hirta, B. nigra, and B. napus var. napus, respectively, in Wagga Wagga and Armatree, NSW, Australia (2). Peters et al. (2) demonstrated that these strains were similar to P. syringae pv. maculicola ICMP 4326 (CFBP 1637), which was recently transferred to Pseudomonas cannabina pv. alisalensis (1). We evaluated these Australian strains to determine if they might also be P. cannabina pv. alisalensis. Amplification of DNA using the BOXA1R primer and PCR resulted in identical DNA fragment banding patterns for Australian strains DAR 33362 and DAR 33363 and P. cannabina pv. alisalensis ICMP 4326 and CFBP 6875. The third Australian strain, DAR 33406, was 90% similar to P. cannabina pv. alisalensis; in contrast, it was only 77% similar to P. syringae pv. maculicola. All strains of P. cannabina pv. alisalensis, including the pathotype strain (CFBP 6866) and all three Australian strains, were lysed by bacteriophage PBS1, which is specific for P. cannabina pv. alisalensis strains (1). To complete Koch's postulates, pathogenicity was evaluated on B. hirta, B. nigra, and B. napus var. napus. In two independent experiments, two plants of each species were inoculated with each Australian strain or a phosphate buffer control treatment. In separate experiments, pathogenicity was evaluated on the differential hosts radish (Raphanus sativus cv. Comet) and broccoli raab (Brassica rapa cv. Sorrento), and plants inoculated with the pathotypes of P. cannabina pv. alisalensis and P. syringae pv. maculicola served as additional control treatments. Inoculum was prepared by growing the bacteria on nutrient agar for 48 h (27°C), suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), and adjusting each suspension to 0.6 OD at 600 nm (approximately 108 CFU/ml). Treatments were applied by spraying until runoff. DAR 33362, DAR 33363, and DAR 33406 caused typical bacterial blight symptoms on B. hirta, B. nigra, and B. napus var. napus. Infected leaves became yellow, followed by the development of small (<2 mm in diameter), angular, water-soaked, and eventually, shot-holed spots. Bacteria isolated from symptomatic tissue following surface disinfestation of tissue with sodium hypochlorite (0.525%) had identical characteristics (rep-PCR DNA fragment banding patterns and phage sensitivity) to the strains used to inoculate the plants. Additionally, DAR 33362, DAR 33363, and DAR 33406, as well as P. cannabina pv. alisalensis, caused symptoms on radish and broccoli raab while P. syringae pv. maculicola and the buffer control did not. These data support the transfer of the Australian crucifer strains, originally identified as P. syringae pv. maculicola, to P. cannabina pv. alisalensis. To our knowledge, this is the first report of a bacterial disease of crucifers caused by P. cannabina pv. alisalensis in Australia. Differentiation of these pathogens will inform crop rotation strategies for disease management. References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) B. J. Peters et al. Plant Pathol. 53:3, 2004.

Microwave-Inactivation of Bacterial Pathogens in Various Controlled Frozen Food Compositions and in a Commercially Available Frozen Food Product

1984 ◽  
Vol 47 (6) ◽  
pp. 458-462 ◽  
Author(s):  
GEORGE T. SPITE
Keyword(s):  
Pathogenic Bacteria ◽  
Food Product ◽  
Microwave Energy ◽  
Microwave Oven ◽  
Frozen Foods ◽  
Frozen Food ◽  
Test Conditions ◽  
Mashed Potatoes ◽  
Microbial Destruction ◽  
Product Species

An assessment was made of the inactivation of pathogenic bacteria by microwave energy in frozen foods using various time-temperature configurations, controlled carbohydrate, lipid, protein, moisture, or food mass levels, and on a commercially prepared product. Species of Salmonella cubana, Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens were separately inoculated into mashed potatoes or one of its controlled variations, giving a concentration range of 105 to 107 cells per gram of food. After freezing, the food was cooked by microwave oven for 3 to 9 min, depending on test conditions. Samples were withdrawn for pathogens and vertical food core temperatures recorded. Survival percentages were calculated and averaged. All species survived the cooking cycle that was least detrimental to the food's palatability. Increased moisture generally enhanced survival. Higher protein or lipid ratios tended to increase the survival of C. perfringens although higher internal temperatures were produced. Sporeforming organisms were generally less susceptible under all test conditions. Addition of whole peas to the mashed potatoes resulted in higher temperatures, but significantly reduced microbial destruction, perhaps by allowing formation of micropockets of cooler food matrices.

scholarly journals Determination of eight carbonyl compounds in aerosols trapped in phosphate buffer saline solutions to support in vitro assessment studies

Talanta ◽  
2018 ◽  
Vol 184 ◽  
pp. 42-49 ◽  
Author(s):  
Roberto Buratto ◽  
Daniela Correia ◽  
Monique Parel ◽  
Maude Crenna ◽  
Mickaël Bilger ◽  
...  
Keyword(s):  
Phosphate Buffer ◽  
Carbonyl Compounds ◽  
Phosphate Buffer Saline ◽  
In Vitro Assessment ◽  
Saline Solutions

Radicidation for Elimination of Salmonellae in Frog Legs

1982 ◽  
Vol 45 (9) ◽  
pp. 820-823 ◽  
Author(s):  
D. P. NERKAR ◽  
N. F. LEWIS
Keyword(s):  
Phosphate Buffer ◽  
Salmonella Spp

The D10 values of three Salmonella spp. often encountered in frog legs, i.e., S. typhimurium, S. enteritidis and S. newport, were found to be between 18 to 30 krad when cells were irradiated at 0–2°C in 0.1 M phosphate buffer, pH 7.0. The radiation sensitivities of these Salmonella spp. increased only marginally when cells were irradiated in frog leg homogenate. The doses of radiation required for eradication of this pathogen in fresh and frozen frog legs were 300 and 400 krad, respectively.

Surface Material, Temperature, and Soil Effects on the Survival of Selected Foodborne Pathogens in the Presence of Condensate

2004 ◽  
Vol 67 (12) ◽  
pp. 2666-2670 ◽  
Author(s):  
J. T. ALLAN ◽  
Z. YAN ◽  
J. L. KORNACKI
Keyword(s):  
Stainless Steel ◽  
Foodborne Pathogens ◽  
Phosphate Buffer ◽  
Salmonella Spp ◽  
Time Intervals ◽  
Porcine Serum ◽  
Reinforced Plastic ◽  
Type Stainless Steel ◽  
Soil Effects ◽  
Material Temperature

The effects of surface type (stainless steel, acetal resin, and fiberglass reinforced plastic wall paneling [FRP]), soil, and temperature on the survival of Listeria monocytogenes, Salmonella spp., and Yersinia enterocolitica, in the presence of condensate were evaluated. Surface coupons—half soiled with sterile porcine serum—were exposed to cell suspensions made from individual five-strain cocktails composed of organisms from the same genus (107 CFU/ml) in Butterfield's phosphate buffer and incubated for 2 h at 25°C allowing attachment of cells to coupon surfaces. Coupons were rinsed to remove unattached cells, incubated at either 4 or 10°C under condensate-forming conditions, and sampled at six time intervals over a 15-day period. For enumeration, cells were removed from the coupons by vigorous shaking in 100 ml of Butterfield's phosphate buffer with 3 g of glass beads and plated on tryptic soy agar with 0.6% yeast extract. Stainless steel did not support the survival of Listeria as well as acetal resin or FRP. Acetal resin and stainless steel were less supportive of Salmonella than FRP. All surfaces supported the survival of Yersinia over the 15-day trial equally. Temperature had little effect on survival of all organisms across all surfaces with one exception. However, Yersinia displayed growth on FRP at 10°C, but death at 4°C. Serum had a protective effect on L. monocytogenes on all surfaces, with populations sustained at significantly (P ≤ 0.05) higher numbers over time than unsoiled coupons. Serum did not effect survival of Salmonella or Yersinia on stainless steel, acetal resin, or FRP.

scholarly journals THE STABILITY OF INFLUENZA VIRUS IN THE PRESENCE OF SALTS

1944 ◽  
Vol 79 (3) ◽  
pp. 285-290 ◽  
Author(s):  
C. A. Knight
Keyword(s):  
Influenza Virus ◽  
Phosphate Buffer ◽  
Protein Concentration ◽  
Distilled Water ◽  
Virus Activity ◽  
Veronal Buffer ◽  
The Stability ◽  
Saline Solutions ◽  
Poor Solvent

The stability of centrifugally purified PR8 influenza virus at pH 7 in 0.001, 0.01, 0.1, and 1.0 M phosphate buffers, in veronal and borate buffers, and in adjusted solutions of saline and distilled water was investigated. The results demonstrate that the stability of this virus can vary considerably at pH 7 depending upon the nature and concentration of the salts present. Borate, veronal, and phosphate buffers at a concentration of about 0.1 M showed almost equal ability to maintain virus activity over several weeks of time at 4°C. In many cases, it may prove inconvenient to use veronal buffer, however, because of the difficulty in determining protein concentration in its presence. The 0.1 M phosphate buffer has proved in tests not described here to be slightly more consistent in preserving virus activity than the borate and may, therefore, be considered slightly superior to the latter. It is apparent that unbuffered saline is a poor solvent for preserving virus activity regardless of pH. The activity of partially inactivated virus in distilled water and in saline solutions was increased ten to 1000 times by diluting such solutions with 0.1 M phosphate buffer. Some reactivation was also effected with veronal but not with borate buffers.

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