The objective of this study was to evaluate the effect of sodium habituation on thermal resistance of Staphylococcus aureus in various ready-to-heat (RTH) sauces. The strain mixture of S. aureus strains KACC10768, KACC10778, KACC11596, KACC13236 and NCCP10862 was habituated up to 9% of NaCl. The inocula of NaCl-habituated and nonhabituated S. aureus were inoculated in 5 g portions of pork cutlet, meat and Carbonara sauces at 7 Log CFU/g, and the samples were vortexed vigorously. The inoculated samples were then exposed to 60 and 70 o C in a water-bath, and survivals of total bacteria and S. aureus were enumerated on tryptic soy agar and mannitol salt agar, respectively, every 30 min for 120 min. At 60 o C, the cell counts of total bacteria and the significant difference in survivals between sodium-habituated and non-habituated S. aureus were observed only in the Carbonara sauce; the tailing effect, which is the period of no reduction of bacterial cell counts, was observed in pork cutlet, meat and Carbonara sauces subjected to 60 o C. At 70 o C, total bacterial populations and sodium-habituated and non-habituated S. aureus cell counts in meat and Carbonara sauce also significantly decreased (p<0.05) after 30 min of heat treatment, followed by the obvious tailing effect. Sodium-habituated S. aureus cell counts in meat and Carbonara sauces were higher (p<0.05) than those of non-habituated S. aureus at 70 o C. The results indicate that sodium habituation of S. aureus cells may increase the thermal resistance of the pathogen in RTH sauces; moreover, heating RTH sauces for a short time before serving may not sufficiently decrease the cell counts of S. aureus, particularly for sodium-habituated strain.
Bacillus cereus strains were inoculated into tryptic soy broth (TSB) and incubated (7-35 o C). Exponential and stationary phase cells were subjected to TSB plus sodium hypochlorite (0-3.6%), hydrogen peroxide (0-0.28%), and acetic acid (0-1.5%). Populations were counted on tryptic soy agar. Linear regression was fitted to survival data to calculate death rates. Cell counts decreased at 7 o C. Differences in growth patterns were observed at 10 o C and 15 o C. Exponential and stationary phase cells showed significant (p<0.05) differences in disinfectant resistance. Strains treated with different disinfectants showed differences in growth and disinfectant resistance during different growth phases.
This study developed predictive models to describe the behavior of Staphylococcus aureus in sweet pumpkin salad. A five‐strain mixture of S. aureus was inoculated in 5‐g portions of sweet pumpkin salad. The samples were stored at 10–30C, and cell counts were enumerated. The growth data were fitted to the Baranyi model to calculate lag‐phase duration (h), maximum specific growth rate (Log cfu/g/h), lower asymptote (Log cfu/g) and upper asymptote (Log cfu/g). The growth parameters were then fitted to secondary models as a function of storage temperature. Dynamic models were also developed for changing temperatures. The model was validated using the observed data, and the root mean square error (RMSE) was calculated. S. aureus growth was observed at 15–30C. RMSE values were 0.428–0.847. The results indicate that the developed mathematical models should be useful in describing the behavior of S. aureus as a function of temperature.Practical ApplicationMany Staphylococcus aureus strains can contaminate sweet pumpkin salad. The salad may be stored at constant and nonisothermal temperatures, which may cause different S. aureus behaviors. Therefore, the developed model could be useful in describing and predicting the behavior of S. aureus with respect to temperature and time.
1) PurposeThe need for hospice palliative care continues to grow as the number of deaths from cancer increases with increasing interest in and need for the management of end stage cancer patients. We conducted this study to determine differences in quantity and cost of drugs used by end-stage cancer patients who were hospitalized in general wards or hospice wards for 7 days before death.2) MethodsAmong patients who died in the hospice ward or the general ward of a university hospital in a metropolitan city (Seoul) from January 2016 to September 2019, patients aged over 18 years with a hospital stay of 8 days or more were selected. A total of 526 patients were selected, including 290 from hospice wards and 236 from general wards.3) ResultsNumbers of PO, injections, and fluid, but not opioids, used in the hospice ward were significantly lower than those in the general ward. Cost of PO, injections, fluid, and total costs were significantly lower in the hospice ward than in the general ward. In the case of opioids, the cost was higher for the hospice ward. Total costs including all drug costs in the hospice ward were significantly lower than those in the general ward. 4) ConclusionCaring for people with terminal cancer in a hospice can lower costs and increase satisfaction for dying patients. Reducing the proportion of patients caring for terminal cancer in general wards and increasing access to hospice services can address health insurance deficits and exhaustion.
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