Biomaterial Database

Optimization of broth recovery for repair of heat-injured Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7. 2019

J-Y Han, and W-J Song, and D-H Kang

Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea.

OBJECTIVE The purpose of this research was to determine optimum conditions for broth recovery of heat-injured Salmonella Typhimurium and Escherichia coli O157:H7. RESULTS Exposure to 55°C for 15 and 25 min, respectively, induced cellular injury to those pathogens. Comparison was made with the commonly used overlay method using selective medium for recovering sublethally injured cells of S. Typhimurium. For E. coli O157:H7, phenol red agar base with 1% sorbitol was used. After cell suspensions were heated at 55°C for selected time intervals, microbes were 10-fold diluted with brain heart infusion (BHI), tryptic soy broth (TSB) and TSB with 0·6% yeast extract (TSBYE) and incubated at 37°C for up to 3 h. At hourly intervals, diluents were plated onto selective medium for recovery. Simultaneously, diluents were plated onto tryptic soy agar (TSA) for recovery of sublethally injured cells. For overlays, diluents were plated onto TSA and overlaid with selective agar after a resuscitation interval. Broth recovery conditions for S. Typhimurium and E. coli O157:H7 were determined to be 1 h in any of the following broth media: BHI, TSB or TSBYE. When liquid resuscitation was applied to sublethally injured cells in food samples (milk), 1 h was also sufficient time for recovery. CONCLUSIONS The broth recovery method is a convenient alternative to conventional recovery methods. CONCLUSIONS Cells sublethally injured by control interventions might not grow on selective medium because they have no resistance to several selective compounds. However, injured cells can recuperate and multiply under conditions sufficient for recovery. To repair and detect heat-injured cells, the overlay method is commonly used but this method has some limitations. This study confirms the effectiveness of liquid resuscitation method on recovery of injured cells. The broth recovery can replace the overlay method due to greater convenience and timesaving.

UI	MeSH Term	Description	Entries
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D005516	Food Microbiology	The presence of bacteria, viruses, and fungi in food and food products. This term is not restricted to pathogenic organisms: the presence of various non-pathogenic bacteria and fungi in cheeses and wines, for example, is included in this concept.	Microbiology, Food
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D000362	Agar	A complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae. It is used as a gel in the preparation of solid culture media for microorganisms, as a bulk laxative, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis.
D001431	Bacteriological Techniques	Techniques used in studying bacteria.	Bacteriologic Technic,Bacteriologic Technics,Bacteriologic Techniques,Bacteriological Technique,Technic, Bacteriological,Technics, Bacteriological,Technique, Bacteriological,Techniques, Bacteriological,Bacteriologic Technique,Bacteriological Technic,Bacteriological Technics,Technic, Bacteriologic,Technics, Bacteriologic,Technique, Bacteriologic,Techniques, Bacteriologic
D012486	Salmonella typhimurium	A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.	Salmonella typhimurium LT2
D015169	Colony Count, Microbial	Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.	Agar Dilution Count,Colony-Forming Units Assay, Microbial,Fungal Count,Pour Plate Count,Spore Count,Spread Plate Count,Streak Plate Count,Colony Forming Units Assay, Microbial,Colony Forming Units Assays, Microbial,Agar Dilution Counts,Colony Counts, Microbial,Count, Agar Dilution,Count, Fungal,Count, Microbial Colony,Count, Pour Plate,Count, Spore,Count, Spread Plate,Count, Streak Plate,Counts, Agar Dilution,Counts, Fungal,Counts, Microbial Colony,Counts, Pour Plate,Counts, Spore,Counts, Spread Plate,Counts, Streak Plate,Dilution Count, Agar,Dilution Counts, Agar,Fungal Counts,Microbial Colony Count,Microbial Colony Counts,Pour Plate Counts,Spore Counts,Spread Plate Counts,Streak Plate Counts
D018869	Heat-Shock Response	A sequence of responses that occur when an organism is exposed to excessive heat. In humans, an increase in skin temperature triggers muscle relaxation, sweating, and vasodilation.	Heat-Shock Reaction,Heat Shock,Heat Shock Stress,Heat Stress,Heat-Stress Reaction,Heat-Stress Response,Heat Shock Reaction,Heat Shock Response,Heat Shock Stresses,Heat Shocks,Heat Stress Reaction,Heat Stress Response,Heat Stresses,Heat-Shock Reactions,Heat-Shock Responses,Heat-Stress Reactions,Heat-Stress Responses,Shock, Heat,Stress, Heat,Stress, Heat Shock
D019453	Escherichia coli O157	A verocytotoxin-producing serogroup belonging to the O subfamily of Escherichia coli which has been shown to cause severe food-borne disease. A strain from this serogroup, serotype H7, which produces SHIGA TOXINS, has been linked to human disease outbreaks resulting from contamination of foods by E. coli O157 from bovine origin.	E coli O157,E coli O157-H7,Escherichia coli O157-H7