Responses of acid-stressed Salmonella Typhimurium in broth and chicken patties to subsequent antimicrobial stress with ɛ-polylysine and combined potassium lactate and sodium diacetate

Jung, Yang Jin; Min, Kyung Jin; Yoon, Ki Sun

doi:10.1016/j.fm.2009.02.007

Cited by 22 publications

(12 citation statements)

References 36 publications

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“…Thus, the stress conditions that resulted in larger modifications in the IR spectra (acidification and alkalinization) also caused the most prominent ultrastructural changes after a 1-log cycle reduction, with a loss of the general cellular shape, disorganization of the genome area, the appearance of blank spaces in the cytoplasm, and the condensation of the cytoplasmic material toward the membrane, which showed a winding shape and, on some occasions, looked disrupted. These morphological features, which probably indicate the existence of DNA degradation and release and the denaturation and precipitation of proteins and other cellular components, agree with previous observations (16,31) for Salmonella cells treated in alkaline and acid environments, respectively. On the other hand, under all of the stress conditions assayed, an increase in the OD 260 and OD 280 of cell-free filtrates was observed, which is indicative of the loss of membrane integrity, since OD 260 and OD 280 values vary as a function of the amount of nucleic acids and proteins released from bacterial cells and, therefore, present in cell-free filtrates (31).…”

Section: Discussionsupporting

confidence: 92%

Changes in Ultrastructure and Fourier Transform Infrared Spectrum of Salmonella enterica Serovar Typhimurium Cells after Exposure to Stress Conditions

Álvarez‐Ordóñez

Prieto

2010

Appl Environ Microbiol

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The effect of exposure to acid (pH 2.5), alkaline (pH 11.0), heat (55°C), and oxidative (40 mM H 2 O 2 ) lethal conditions on the ultrastructure and global chemical composition of Salmonella enterica serovar Typhimurium CECT 443 cells was studied using transmission electron microscopy and Fourier transform infrared spectroscopy (FT-IR) combined with multivariate statistical methods (hierarchical cluster analysis and factor analysis). Infrared spectra exhibited marked differences in the five spectral regions for all conditions tested compared to those of nontreated control cells, which suggests the existence of a complex bacterial stress response in which modifications in a wide variety of cellular compounds are involved. The visible spectral changes observed in all of the spectral regions, together with ultrastructural changes observed by transmission electron microscopy and data obtained from membrane integrity tests, indicate the existence of membrane damage or alterations in membrane composition after heat, acid, alkaline, and oxidative treatments. Results obtained in this study indicate the potential of FT-IR spectroscopy to discriminate between intact and injured bacterial cells and between treatment technologies, and they show the adequacy of this technique to study the molecular aspects of bacterial stress response.Salmonella spp. are an important cause of bacterial foodborne disease all over the world, causing a diversity of illnesses that include typhoid fever, gastroenteritis, and septicemia (11). According to epidemiological data from the European Union, a total of 131,468 laboratory-confirmed salmonellosis cases were reported in 2008, with two serovars, Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis, being responsible for 79.9% of all cases (13). The detection and identification of pathogens in foods are a basic cornerstone of food safety, because they make it possible to identify sources of contamination, provide data on the evaluation of risk reduction measures, and identify the food chain operations, processes, batches, or products representing a threat to public health. Furthermore, they also are fundamental in the epidemiological investigation of food-borne diseases. The presence of stress-injured bacterial cells in foods represents a challenge to those involved in food quality assurance, as routine microbiological procedures may yield negative results for sublethally injured cells. Thus, food could be presumed to be safe and free from pathogenic cells but during storage become dangerous due to the recovery and growth of previously injured cells.Given the fact that bacterial cells react to the different environmental stress conditions by inducing structural and physiological changes, Fourier transform infrared (FT-IR) spectroscopy, which reflects the biochemical composition of the cellular constituents of bacteria that include water, fatty acids, proteins, polysaccharides, and nucleic acids (26), should be able to monitor the changes occurring in bacterial ce...

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Section: Discussionsupporting

confidence: 92%

Changes in Ultrastructure and Fourier Transform Infrared Spectrum of Salmonella enterica Serovar Typhimurium Cells after Exposure to Stress Conditions

Álvarez‐Ordóñez

Prieto

2010

Appl Environ Microbiol

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“…Jung and others (14) investigated growth of Salmonella Typhimurium (ATCC 13311) from an initial density of 3 log/ml in BHI broth incubated at 10uC for 20 days. They reported a 5-log increase of Salmonella Typhimurium after 20 days, which is much greater than that of Salmonella Typhimurium DT104 at 10uC in the current study.…”

Section: Discussionmentioning

confidence: 99%

Development and Validation of a Predictive Microbiology Model for Survival and Growth of Salmonella on Chicken Stored at 4 to 12°C

Oscar

2011

Journal of Food Protection

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Salmonella spp. are a leading cause of foodborne illness. Mathematical models that predict Salmonella survival and growth on food from a low initial dose, in response to storage and handling conditions, are valuable tools for helping assess and manage this public health risk. The objective of this study was to develop and to validate the first predictive microbiology model for survival and growth of a low initial dose of Salmonella on chicken during refrigerated storage. Chicken skin was inoculated with a low initial dose (0.9 log) of a multiple antibiotic-resistant strain of Salmonella Typhimurium DT104 (ATCC 700408) and then stored at 4 to 12 °C for 0 to 10 days. A general regression neural network (GRNN) model that predicted log change of Salmonella Typhimurium DT104 as a function of time and temperature was developed. Percentage of residuals in an acceptable prediction zone, from -1 (fail-safe) to 0.5 (fail-dangerous) log, was used to validate the GRNN model by using a criterion of 70% acceptable predictions. Survival but not growth of Salmonella Typhimurium DT104 was observed at 4 to 8 °C. Maximum growth of Salmonella Typhimurium DT104 during 10 days of storage was 0.7 log at 9 °C, 1.1 log at 10 °C, 1.8 log at 11 °C, and 2.9 log at 12 °C. Performance of the GRNN model for predicting dependent data (n=163) was 85% acceptable predictions, for predicting independent data for interpolation (n=77) was 84% acceptable predictions, and for predicting independent data for extrapolation (n=70) to Salmonella Kentucky was 87% acceptable predictions. Thus, the GRNN model provided valid predictions for survival and growth of Salmonella on chicken during refrigerated storage, and therefore the model can be used with confidence to help assess and manage this public health risk.

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“…CAA and CAR were the most effective acid and essential oil, respectively (unpublished data). POL, a cationic surfactant, was not as effective as CAA or CAR against the pathogen, but it was included in the present study based on previous published reports (6,11,14) of its antimicrobial activity against Salmonella and other foodborne pathogens.…”

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confidence: 99%

Antimicrobials for Reduction of Salmonella Contamination in Uncooked, Surface-Browned Breaded Chicken Products

Moschonas

Geornaras

Stopforth³

et al. 2012

Journal of Food Protection

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Surface-browned but uncooked frozen breaded chicken products have been associated with salmonellosis outbreaks due to inadequate or no cooking of the products before consumption. This study was conducted to evaluate the effect of three antimicrobials against Salmonella during manufacture of a surface-browned, uncooked frozen breaded chicken meat product. Fresh chicken breast meat portions (5 by 5 by 5 cm) were inoculated (4 to 5 log CFU/g) with Salmonella and mixed with caprylic acid (CAA; 0.5 and 1.0%), carvacrol (CAR; 0.3 and 0.5%), ε-polylysine (POL; 0.125 and 0.25%), or distilled water (control). Sodium chloride (1.2%) and sodium tripolyphosphate (0.3%) were added to all treatments, and the mixtures were ground (5% total moisture enhancement level) and formed into portions (9 by 5 by 3 cm). The products were breaded and surface browned by baking in an oven (208°C for 15 min) or deep frying in vegetable oil (190°C for 15 s), packaged in polyethylene bags, and stored at -20°C for 7 days. Total reductions of inoculated Salmonella in untreated control oven- or fryer-browned products after frozen storage were 1.2 and 0.8 log CFU/g, respectively. In comparison, treatment with CAA, CAR, or POL reduced initial pathogen counts by 3.3 to >4.5, 4.1 to >4.7, and 1.1 to 1.6 log CFU/g, respectively, regardless of the antimicrobial concentration and browning method. Treatment with 1.0% CAA (oven browned) or 0.5% CAR (oven or fryer browned) reduced Salmonella to nondetectable levels (<0.3 log CFU/g) in stored frozen products. These data may be useful for development of suitable antimicrobial treatments to reduce the risk of Salmonella contamination in surface-browned, uncooked frozen breaded chicken products.

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Responses of acid-stressed Salmonella Typhimurium in broth and chicken patties to subsequent antimicrobial stress with ɛ-polylysine and combined potassium lactate and sodium diacetate

Cited by 22 publications

References 36 publications

Changes in Ultrastructure and Fourier Transform Infrared Spectrum of Salmonella enterica Serovar Typhimurium Cells after Exposure to Stress Conditions

Changes in Ultrastructure and Fourier Transform Infrared Spectrum of Salmonella enterica Serovar Typhimurium Cells after Exposure to Stress Conditions

Development and Validation of a Predictive Microbiology Model for Survival and Growth of Salmonella on Chicken Stored at 4 to 12°C

Antimicrobials for Reduction of Salmonella Contamination in Uncooked, Surface-Browned Breaded Chicken Products

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