Determining the disinfection of textiles in compressed carbon dioxide using various indicator microbes

Application of RSM Method for Optimization of Geraniol Transformation Process in the Presence of Garnet

This paper presents the results of tests obtained for the transformation of geraniol in the presence of garnet as a catalyst by the response surface method (RSM). The method analyzed the influence of the following parameters: a temperature of 50-150 °C, a catalyst concentration (garnet) of 1.0-10.0 wt% and a reaction time of 0.25-24 h. Response functions included the conversion of geraniol (GA), selectivity for conversion to neral (NE) and selectivity for conversion to citronellol (CL). In addition, the influence of all control parameters on each of the response parameters is presented in the form of second-order polynomials. The optimal parameters of the geraniol transformation process were a temperature of 55 °C, a catalyst concentration of 5 wt% and a reaction time of 2 h, for which high values of the GA conversion function and the selectivity of conversion to NE and CL were obtained. For the GA conversion, the optimum was obtained at 94 mol% at 60 °C, a catalyst concentration of 5.0 wt% and a reaction time of 2 h. For NE selectivity, the optimum value was reached at 49 mol% at 60 °C, a catalyst concentration equal to 2.5 (5.0) wt% mole and a reaction time of almost 2 h. For CL selectivity, the optimum value of 49 mol% was obtained for control factors: a temperature equal to 20 °C, a catalyst concentration equal to 5.0 wt% and a response time equal to 2 h. The optimal set of control factors for all power factors is characterized by a temperature of 55 °C, a catalyst concentration of 5 wt% and a reaction time of 2 h.

Decontamination Efficiency of Thermal, Photothermal, Microwave, and Steam Treatments for Biocontaminated Household Textiles

With the outbreak of the COVID-19 pandemic, textile laundering hygiene has proved to be a fundamental measure in preventing the spread of infections. The first part of our study evaluated the decontamination efficiency of various treatments (thermal, photothermal, and microwave) for bio contaminated textiles. The effects on textile decontamination of adding saturated steam into the drum of a household textile laundering machine were investigated and evaluated in the second part of our study. The results show that the thermal treatment, conducted in a convection heating chamber, provided a slight reduction in efficiency and did not ensure the complete inactivation of Staphylococcus aureus on cotton swatches. The photothermal treatment showed higher reduction efficiency on contaminated textile samples, while the microwave treatment (at 460 W for a period of 60 s) of bio contaminated cotton swatches containing higher moisture content provided satisfactory bacterial reduction efficiency (more than 7 log steps). Additionally, the treatment of textiles in the household washing machine with the injection of saturated steam into the washing drum and a mild agitation rhythm provided at least a 7 log step reduction in S. aureus. The photothermal treatment of bio contaminated cotton textiles showed promising reduction efficiency, while the microwave treatment and the treatment with saturated steam proved to be the most effective.

Level of decontamination after washing textiles at 60°C or 70°C followed by tumble drying

BACKGROUND

Several major outbreaks in healthcare facilities have occurred with the emergence of multi-resistant bacteria. A possible route for dissemination is the hospital textiles and inadequate laundering of them. The aim of this study was to develop an easy-to-use method for simulating the laundering process of hospital textiles, and thereafter apply the method when evaluating the decontaminating efficacy of two different washing temperatures.

METHODS

The laundering process, including tumble drying, took place at two professional laundries. Enterococcus faecium was used as bioindicator.

RESULTS

The results showed that a lowering of the washing temperature from 70°C to 60°C did not affect the decontamination efficacy; the washing cycle alone reduced the number of bacteria with 3-5 log10 CFU, whereas the following tumble drying reduced the bacterial numbers with another 3-4 log10 CFU, yielding the same final result independent of washing temperature. Without tumble drying, there was an obvious risk of adding non-fermenting gram-negative bacteria to the fabric. These bacteria originated from the washing cycle.

CONCLUSION

A simple method to simulate hospital laundering was developed. To save energy, it is possible to use a washing temperature of 60°C, but the washing cycle should be followed by tumble drying, and the whole laundering process needs to be monitored to maintain sufficient textile hygiene.