RpoS Function in Salmonella Typhimurium LT2 Monitored in a Skim Milk Model Food

1999 ◽  
Vol 62 (1) ◽  
pp. 70-72 ◽  
Author(s):  
JACQUELYN M. THOMPSON ◽  
GORDON S. A. B. STEWART ◽  
CHRISTINE E. R. DODD
Keyword(s):  
Salmonella Typhimurium ◽  
Food Systems ◽  
Environmental Control ◽  
Skim Milk ◽  
Logarithmic Phase ◽  
Global Regulator ◽  
Reporter Construct ◽  
Nutrient Media ◽  
Expression Of Genes ◽  
Model Food

In Salmonella Typhimurium, the stationary phase sigma factor RpoS regulates the expression of genes associated with adaptation, survival, and virulence. Expression of rpoS is known to be under environmental control and yet, to date, there have been no studies that assess the expression of this global regulator in real food systems. Skim milk represents a useful model food; using an spvRA::luxCDABE reporter construct, we have determined RpoS availability from an inoculum of Salmonella Typhimurium LT2. We report that RpoS activity increases exponentially at the end of the logarithmic phase of growth, consistent with data from nutrient media.

Functionality of Modified Plant Proteins in Model Food Systems

1984 ◽  
Vol 17 (4) ◽  
pp. 202-208 ◽  
Author(s):  
A.T. Paulson ◽  
M.A. Tung ◽  
M.R. Garland ◽  
S. Nakai
Keyword(s):  
Food Systems ◽  
Plant Proteins ◽  
Model Food

Antioxidant potential and antimicrobial efficacy of seaweed (Himanthalia elongata) extract in model food systems

2013 ◽  
Vol 26 (4) ◽  
pp. 1823-1831 ◽  
Author(s):  
Sabrina Cox ◽  
Grace Hamilton Turley ◽  
Gaurav Rajauria ◽  
Nissreen Abu-Ghannam ◽  
Amit Kumar Jaiswal
Keyword(s):  
Food Systems ◽  
Antioxidant Potential ◽  
Antimicrobial Efficacy ◽  
Himanthalia Elongata ◽  
Model Food

Expression of Genes Encoding the RhtB Family Proteins Depends on the Global Regulator Lrp

2005 ◽  
Vol 39 (3) ◽  
pp. 331-335 ◽  
Author(s):  
E. A. Kutukova ◽  
N. P. Zakataeva ◽  
V. A. Livshits
Keyword(s):  
Global Regulator ◽  
Expression Of Genes ◽  
Genes Encoding

Buffering capacity of protein-based model food systems in the context of gastric digestion

2019 ◽  
Vol 10 (9) ◽  
pp. 6074-6087 ◽  
Author(s):  
Yamile A. Mennah-Govela ◽  
R. Paul Singh ◽  
Gail M. Bornhorst
Keyword(s):  
Protein Content ◽  
Surface Area ◽  
Food Systems ◽  
Buffering Capacity ◽  
Gastric Digestion ◽  
Model Food ◽  
Standardized Method ◽  
The Impact

A standardized method to measure and quantify buffering capacity in the context of gastric digestion is proposed and the impact of protein content and surface area on buffering capacity was observed.

Behavior of Flavor Compounds in Model Food Systems:  a Thermodynamic Study

2003 ◽  
Vol 51 (5) ◽  
pp. 1393-1398 ◽  
Author(s):  
Ellen Philippe ◽  
Anne-Marie Seuvre ◽  
Bernard Colas ◽  
Virginie Langendorff ◽  
Christine Schippa ◽  
...  
Keyword(s):  
Food Systems ◽  
Thermodynamic Study ◽  
Flavor Compounds ◽  
Model Food

Spray Method for Recovery of Heat-Injured Salmonella Typhimurium and Listeria monocytogenes

2012 ◽  
Vol 75 (10) ◽  
pp. 1867-1872 ◽  
Author(s):  
KYEONG-HWAN BACK ◽  
SANG-OH KIM ◽  
KI-HWAN PARK ◽  
MYUNG-SUB CHUNG ◽  
DONG-HYUN KANG
Keyword(s):  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Recovery Rate ◽  
Skim Milk ◽  
Selective Media ◽  
Spray Method ◽  
Selective Agar ◽  
Overlay Method ◽  
Peptone Water ◽  
Pathogen Recovery

Selective agar is inadequate for supporting recovery of injured cells. During risk assessment of certain foods, both injured and noninjured cells must be enumerated. In this study, a new method (agar spray method) for recovering sublethally heat-injured microorganisms was developed and used for recovery of heat-injured Salmonella Typhimurium and Listeria monocytogenes. Molten selective agar was applied as an overlay to presolidified nonselective tryptic soy agar (TSA) by spray application. Heat-injured cells (55°C for 10 min in 0.1% peptone water or 55°C for 15 min in sterilized skim milk) were inoculated directly onto solidified TSA. After a 2-h incubation period for cell repair, selective agar was applied to the TSA surface with a sprayer, and the plates were incubated. The recovery rate for heat-injured Salmonella Typhimurium and L. monocytogenes with the spray method was compared with the corresponding rates associated with TSA alone, selective media alone, and the conventional overlay method (selective agar poured on top of resuscitated cells grown on TSA and incubated for 2 h). No significant differences (P > 0.05) were found in pathogen recovery obtained with TSA, the overlay method, and the spray method. However, a lower recovery rate (P < 0.05) was obtained for isolation of injured cells on selective media. Overall, these results indicate that the agar spray method is an acceptable alternative to the conventional overlay method and is a simpler and more convenient approach to recovery and detection of injured cells.

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