scholarly journals A modified Weibull model for growth and survival of Listeria innocua and Salmonella Typhimurium in chicken breasts during refrigerated and frozen storage

2012 ◽  
Vol 91 (6) ◽  
pp. 1482-1488 ◽  
Author(s):  
A.K. Pradhan ◽  
M. Li ◽  
Y. Li ◽  
L.C. Kelso ◽  
T.A. Costello ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Frozen Storage ◽  
Weibull Model ◽  
Listeria Innocua ◽  
Growth And Survival ◽  
Modified Weibull

Survival Rate of Salmonella on Cooked Pig Ear Pet Treats at Refrigerated and Ambient Temperature Storage

2014 ◽  
Vol 77 (1) ◽  
pp. 50-56 ◽  
Author(s):  
PETER J. TAORMINA
Keyword(s):  
Survival Rate ◽  
Salmonella Typhimurium ◽  
Room Temperature ◽  
Weibull Model ◽  
Salmonella Newport ◽  
Human Salmonellosis ◽  
Salmonella Serotypes ◽  
Safety Assessments ◽  
Modified Weibull ◽  
Temperature Storage

Pet treats, including pig ears, have been implicated as vehicles of human salmonellosis, and Salmonella has been isolated on commercially produced pig ears. Therefore, behavior of the pathogen on this very low water activity (aw) pet treat is of interest. The survival of Salmonella serotypes Newport and Typhimurium DT104 was measured on natural (aw 0.256) and smoked (aw 0.306) pig ear pet treat products inoculated at ca. 6.5 log CFU per sample and stored at 4.4 or 22°C for 365 days. Surviving populations of Salmonella were enumerated periodically, and a modified Weibull model was used to fit the inactivation curves for log populations. After 14 days, the decline of Salmonella was significantly (P < 0.05) greater at 22°C than at 4.4°C. By 365 days of storage at 4.4°C, Salmonella Typhimurium DT104 declined by 2.19 log on smoked pig ears and 1.14 log on natural pig ears, while Salmonella Newport declined by 4.20 log on smoked pig ears and 2.08 log on natural pig ears. Populations of Salmonella Typhimurium DT104 on refrigerated natural pig ears rebounded between day 152 (3.21 log CFU per sample) and day 175 (4.79 log CFU per sample) and rose gradually for the duration of the study to 5.28 log CFU per sample. The model fits for survival rate of Salmonella on pig ears at 4.4°C show a rapid initial decline followed by a long tailing effect. Salmonella Typhimurium DT104 on natural pig ears at 4.4°C had the slowest rate of reduction. At 22°C Salmonella declined nonlinearly by >4.5 log for each combination of serotype and pig ear type at 22°C but remained detectable by enrichment. The model parameter for days to first decimal reduction of Salmonella on pig ears was two to three times higher at 4.4°C compared with 22°C, demonstrating that Salmonella slowly declines on very low aw refrigerated pet treats and more rapidly at room temperature. This information may be useful for pet treat safety assessments.

Effect of rat polymorphonuclear leukocyte granule components on the growth and survival of Pseudomonas aeruginosa and Salmonella typhimurium

1983 ◽  
Vol 29 (10) ◽  
pp. 1339-1343 ◽  
Author(s):  
M. C. Modrzakowski ◽  
D. Dosch-Meier ◽  
R. L. Hodinka
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Activity ◽  
Salmonella Typhimurium ◽  
Polymorphonuclear Neutrophils ◽  
Growth Enhancement ◽  
Growth And Survival ◽  
Whole Cells ◽  
Phosphate Buffered Saline ◽  
Antimicrobial Assay ◽  
Enhancement Property

Granule contents from rat polymorphonuclear neutrophils were prepared by extraction with 0.2 M acetate buffer (pH 4.0), dialyzed against phosphate-buffered saline (pH 7.0), and tested for bactericidal activity against selected target bacteria. Salmonella typhimurium LT-2 and a series of progressively rough lipopolysaccharide outer membrane mutants derived from it were used to monitor antimicrobial activity. Although an antimicrobial potential was present in rat granule contents for S. typhimurium, the growth of Pseudomonas aeruginosa PAO-1 in antimicrobial assay mixtures containing rat granule contents was substantially enhanced over control values. The growth enhancement property of the granule protein was heat resistant and promoted increased oxygen consumption by whole cells.

Effectiveness of a Laboratory-Scale Vertical Tower Static Chamber Steam Pasteurization Unit against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua on Prerigor Beef Tissue†

2004 ◽  
Vol 67 (8) ◽  
pp. 1630-1633 ◽  
Author(s):  
DEANNA RETZLAFF ◽  
RANDALL PHEBUS ◽  
ABBEY NUTSCH ◽  
JAMES RIEMANN ◽  
CURTIS KASTNER ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Cold Water ◽  
Laboratory Scale ◽  
Listeria Innocua ◽  
Steam Treatment ◽  
Escherichia Coli O157 ◽  
Tissue Samples ◽  
Before And After ◽  
Steam Pasteurization

A laboratory-scale vertical tower steam pasteurization unit was evaluated to determine the antimicrobial effectiveness of different exposure times (0, 3, 6, 12, and 15 s) and steam chamber temperatures (82.2, 87.8, 93.3, and 98.9°C) against pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria innocua) inoculated onto prerigor beef tissue. Samples were collected and microbiologically analyzed immediately before and after steam treatment to quantify the effectiveness of each time-temperature combination. The 0-s exposure at all chamber temperatures (cold water spray only, no steam treatment) was the experimental control and provided ≤0.3 log CFU/cm2 reductions. Chamber temperatures of 82.2 and 87.8°C were ineffective (P > 0.05) at all exposure times. At 93.3°C, significant reductions (>1.0 log CFU/cm2) were observed at exposure times of ≥6 s, with 15 s providing approximately 1 log cycle greater reductions than 12 s of exposure. The 98.9°C treatment was consistently the most effective, with exposure times of ≥9 s resulting in >3.5 log CFU/cm2 reductions for all pathogens.

Antibiotic Resistance of Salmonella spp. and Listeria spp. Isolates from Traditionally Made Fresh Sausages in Greece

1998 ◽  
Vol 61 (10) ◽  
pp. 1378-1380 ◽  
Author(s):  
AMIN ABRAHIM ◽  
ANNA PAPA ◽  
NIKOLAOS SOULTOS ◽  
IOANNIS AMBROSIADIS ◽  
ANTONIS ANTONIADIS
Keyword(s):  
Antibiotic Resistance ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Salmonella Enteritidis ◽  
Antibacterial Agents ◽  
Listeria Innocua ◽  
Salmonella Spp ◽  
Listeria Welshimeri ◽  
Butcher Shops

Sixty-five samples of traditionally made fresh sausages obtained from retail shops and butcher shops in northem Greece were screened for the presence of Salmonella spp. and Listeria spp. Salmonella spp. were found in 20% of the samples tested (54% Salmonella typhimurium and 46% Salmonella enteritidis). The prevalence of Listeria spp. in the samples was 26% (12% Listeria monocytogenes, 76% Listeria innocua, and 12% Listeria welshimeri). Nine of 13 Salmonella isolates were found to be resistant to ampicillin and 4 of 13 showed intermediate sensitivity; 1 of 13 was found to be resistant to chloramphenicol and 1 of 13 to tetracycline. Two strains of Salmonella typhimurum were multiresistant (resistant to ampicillin, chloramphenicol, and norfloxacin). All Listeria isolates were sensitive to the antibacterial agents tested that are commonly used for the treatment of human listeriosis.

Validation of the Use of Organic Acids and Acidified Sodium Chlorite To Reduce Escherichia coli O157 and Salmonella Typhimurium in Beef Trim and Ground Beef in a Simulated Processing Environment

2006 ◽  
Vol 69 (8) ◽  
pp. 1802-1807 ◽  
Author(s):  
K. HARRIS ◽  
M. F. MILLER ◽  
G. H. LONERAGAN ◽  
M. M. BRASHEARS
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Frozen Storage ◽  
Ground Beef ◽  
Sodium Chlorite ◽  
Escherichia Coli O157 ◽  
Refrigerated Storage ◽  
E Coli ◽  
Log Reduction ◽  
Antimicrobial Treatments

A study was conducted to determine if acidified sodium chlorite (1,200 ppm) and acetic and lactic acids (2 and 4%) were effective in reducing foodborne pathogens in beef trim prior to grinding in a simulated processing environment. The reduction of Salmonella Typhimurium and Escherichia coli O157:H7 at high (4.0 log CFU/g) and low (1.0 log CFU/g) inoculation doses was evaluated at various processing steps, including the following: (i) in trim just after treatment application, (ii) in ground beef just after grinding, (iii) in ground beef 24 h after refrigerated storage, (iv) in ground beef 5 days after refrigerated storage, and (v) in ground beef 30 days after frozen storage. All antimicrobial treatments reduced the pathogens on the trim inoculated with the lower inoculation dose to nondetectable numbers in the trim and in the ground beef. There were significant reductions of both pathogens in the trim and in the ground beef inoculated with the high inoculation doses. On the trim itself, E. coli O157:H7 and Salmonella Typhimurium were reduced by 1.5 to 2.0 log cycles, with no differences among all treatments. In the ground beef, the organic acids were more effective in reducing both pathogens than the acidified sodium chlorite immediately after grinding, but after 1 day of storage, there were no differences among treatments. Overall, in the ground beef, there was a 2.5-log reduction of E. coli O157:H7 and a 1.5-log reduction of Salmonella Typhimurium that was sustained over time in refrigerated and frozen storage. Very few sensory differences between the control samples and the treated samples were detected by a consumer panel. Thus, antimicrobial treatments did not cause serious adverse sensory changes. Use of these antimicrobial treatments can be a promising intervention available to ground beef processors who currently have few interventions in their process.

scholarly journals Effects of Temperature and Moisture on Sporulation and Infection by Pseudoperonospora cubensis

Plant Disease ◽  
2017 ◽  
Vol 101 (4) ◽  
pp. 562-567 ◽  
Author(s):  
Shiling Sun ◽  
Sen Lian ◽  
Shulian Feng ◽  
Xiangli Dong ◽  
Caixian Wang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Downy Mildew ◽  
Weibull Model ◽  
Infection Process ◽  
Effect Of Temperature ◽  
Effective Control ◽  
Pseudoperonospora Cubensis ◽  
Cucumber Downy Mildew ◽  
Effects Of Temperature ◽  
Modified Weibull

Cucumber downy mildew, caused by Pseudoperonospora cubensis, is a worldwide disease that causes severe damage to cucumber production. The effects of temperature and moisture on sporulation and infection by P. cubensis were investigated by inoculating cucumber (‘85F12’) cotyledons with sporangia and examining the sporangia produced on the inoculated cotyledons under artificially controlled environments. The result showed that the temperature required for sporangium infection by P. cubensis and sporulation of the downy mildew lesions occurred at 5 to 30°C. The optimal temperature estimated by the fitted model was 18.8°C for sporangium infection and 16.2°C for downy mildew lesion sporulation. The pathogen formed plenty of sporangia when disease cotyledons were wetted or in the environment with relative humidity = 100%. The downy mildew lesions produced only a few sporangia when placed in the environment with relative humidity = 90%. The inoculated cotyledons, which incubated for 5 days at about 20°C in a dry greenhouse, began to form sporangia 4 h after being wetted when incubated in darkness. The quantity of sporangia produced on the downy mildew lesions increased with extension of incubating period (within 12 h), and the relationship between produced sporangia and the incubation period at 15, 20, and 25°C can be described by three exponential models. The observed minimum wetness durations (MWD) required for sporangia to complete the infection process and cause downy mildew were 12, 4, 2.5, 1, 1, and 6 h for 5, 10, 15, 20, 25, and 30°C, respectively. The effect of temperature and wetness duration on infection by sporangia of P. cubensis can be described by the modified Weibull model. The shortest MWD was 0.45 h, about 27 min, estimated by model. The experimental data and models will be helpful in the development of forecasting models and effective control systems for cucumber downy mildew.

Reduction of Listeria monocytogenes and Salmonella Typhimurium on Blueberries through Brief Exposure to Antimicrobial Solutions Coupled with Freezing

2019 ◽  
Vol 82 (6) ◽  
pp. 926-930 ◽  
Author(s):  
DAVID F. BRIDGES ◽  
SHRAVANI TADEPALLI ◽  
RYAN ANDERSON ◽  
RONG ZHANG ◽  
VIVIAN C. H. WU
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Acid Treatment ◽  
Frozen Storage ◽  
Short Exposure ◽  
Antimicrobial Effectiveness

ABSTRACT This study evaluated the efficacy of different brief-exposure antibacterial washes (≤3 min) coupled with frozen storage against Listeria monocytogenes and Salmonella Typhimurium on blueberries. Inoculated berries where treated with sodium hypochlorite (NaOCl, 200 ppm), chlorine dioxide (15 ppm), ozone (3 and 5 ppm), or lactic acid (2%) for short exposure times (10 s, 1 min, or 3 min), and antibacterial effectiveness was determined with or without an additional freezing hurdle (−12°C, 1 week). Wash treatments alone resulted maximum log reductions from 1.0 to 2.8, while the additional freezing step increased this to a range from 3.7 to 6.6. The greatest reduction of L. monocytogenes (6.6 log) and Salmonella Typhimurium (5.3 log) was observed after freezing combined with 3 min of exposure to 2% lactic acid or 200 ppm of NaOCl, respectfully. After treatment, no residue was measured by the methodologies used. However, lactic acid treatment resulted in changes of color and aroma. In conclusion, wash treatments of blueberries using short exposure times had antimicrobial effectiveness (1.0 to 2.8 log reductions) and can be enhanced by coupling with freezing. HIGHLIGHTS

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