Hochdruckinaktivierung von Mikroorganismen – mit Dynamik zum quasi‐kontinuierlichen Prozess

Static high pressure treatment has become a gentle alternative in sterilization of fluids, but due to high costs, this technology is currently restricted to high‐quality products. The innovative use of dynamic high pressure has the potential to overcome these restrictions as the introduction of additional process parameters allows for amplification of lethal effects on microorganisms. In addition, through the possibility to further convey the product during low‐pressure periods, the dynamic treatment also enables quasi‐continuous modes of operation, which opens a broader field of applications.     

Effect of standard phenolic compounds and olive oil phenolic extracts on acrylamide formation in an emulsion system

In this work the effect of standard phenolic compounds such as trolox, phenolic acids (ferulic, gallic, protocatechuic and caffeic acid) and secoiridoids, extracted from virgin olive oil (VOO), on acrylamide formation in an emulsion system was investigated. The emulsion system was heated in an oil bath at different temperatures and for different periods of time. At 105 and 115 °C the generated amounts of acrylamide were negligible during the monitoring time. At 125 °C addition of standard phenolic compounds reduced acrylamide formation which was more pronounced at initial time of heating (20 min) reaching up to 70%. Protocatechuic and gallic acid were more effective than trolox, caffeic and ferulic acid in acrylamide reduction at the final time intervals of heating (30–60 min). On the contrary, addition of VOO extract in the emulsion system resulted in a remarkable increase of acrylamide level, which was ascribed to secoiridoids’ structure containing aldehydic groups.     

Power-law foods in continuous coiled sterilisers

The heating, holding and cooling section of the high temperature region (T>100°C) of coiled UHT-sterilisers were simulated three-dimensionally to assess the impact of centrifugal and buoyant forces on viscous power-law food products. For a wide range of curvature (De=0-500), heat transfer, lethality development and thiamine concentration were analysed.Curvature and pseudoplasticity substantially increase heat transfer and render the axial velocity profile more uniform. As a result, processing times in heater, holder and cooler can be shorter, thus greatly improving thiamine retention. Significant lethality accumulated in the heating section, but the cooling section contributed very little to product sterility. Buoyant forces were shown to be of minor importance in coiled steriliser flow at the current process conditions.     

Tonometer prism sterilisation: a local and UK national survey.

PURPOSE: First to audit local adherence to a protocol of use of an alcohol wipe for each tonometry, and secondly to assess current practice nationally in the UK. METHOD: The audit was carried out at two units: The West Kent Eye Centre at the Princess Royal University Hospital (Orpington, UK) and Queen Mary's Hospital (Sidcup, UK). The standard set for this audit was 100% sterilisation. During a 1-week period in November 2005, the number of alcohol wipes was counted in each consultation room after outpatient clinics, with the doctors being assessed blind to the survey. The number of Goldman applanation tonometry intra-ocular pressures recorded by each clinician was counted by inspection of the medical records of patients seen. Secondly, departments listed in the UK Directory of Training Posts were contacted by telephone and the senior nurse was interviewed. They were asked directly about their department's tonometer prism sterilisation and management. RESULTS: The local audit showed only 54% of tonometry measurements were associated with sterilisation using an alcohol-impregnated wipe. The national survey included 140 of the 152 UK training departments. Thirty-three (23.6%) departments used disposable tonometer prisms routinely. The remaining 107 (76.4%) used non-disposable prisms. Eighty-five (60.7%) departments provided sodium hypochlorite for prism sterilisation, with 69 (81.2%) of these departments providing more than one prism/clinician to allow full exposure to the disinfectant. Twenty-two (15.7%) departments used alcohol wipes. Only 8 (7.5%) of the 107 departments using non-disposable prisms tracked these prisms, despite Royal College of Ophthalmologists guidelines that they should be. These same 8 (7.5%) departments replaced the non-disposable prisms as per manufacturer guidelines. 19.3% of charge nurses were aware of a policy for tonometry in patients with, or at risk of, prion disease. CONCLUSIONS: This study highlights that sterilisation of tonometer prisms was inconsistent in a local audit. Nationally, practices were varied. The majority of ophthalmology departments continued to use non-disposable tonometer prisms, but few seemed aware of the Royal College of Ophthalmologists' recommendation that disposable prisms are used in patients at risk of prion disease, and few track tonometer heads or replace them according to manufacturers guidelines. Use of disposable tonometer prisms would seem to reduce concerns about sterilisation, as well as prevent spread of common pathogens.     

Effect of Ag/N codoping on photoactivity of TiO2 thin film

Abstract

Nano Ag/N–TiO₂ films with porous hadites as carriers have been successfully prepared by a modified sol–gel process. The performance of the films was characterised by X-ray diffraction, UV-vis and energy dispersive X-ray spectroscopy. The photocatalytic activities and sterilisations of the films were estimated with the waste water contained oil and the fresh cocci as polluted models. The experiments showed that the codoping of Ag and N modified observably the photocatalytic activity of TiO₂. The degradation rate of Ag/N–TiO₂ films on oil in water and bacteria was three times more than pure TiO₂ films on porous hadites. The porous hadites loaded Ag/N–TiO₂ films may be used for waste water processing, sterilisation and filtering.     

Validierung der Beständigkeit von ZrO2‐Minikugeln gegenüber Heißdampfsterilisation

Validation of the Resistance of ZrO₂‐Mini Balls against Hot Vapour Sterilisation Mini‐balls are used in bearings of dental drills. As the bearings as well as the drills are hot vapour sterilised, the bearings are operated under non‐lubricated conditions. In the present study, Raman scattering experiments show that hot vapour sterilisations of Y₂O₃ stabilised ZrO₂‐Mini‐balls lead to a phase transition from tetragonal to monoclinic ZrO₂. This phase transition finally causes the failure of ZrO₂‐Mini‐balls under the tribological conditions typical for dental drills. If, however, the ZrO₂‐Mini‐balls are stabilised using CeO₂, such hot vapour sterilisation induced phase transitions could not be observed. Subsequent tribological experiments prove that CeO₂ stabilised ZrO₂‐Mini‐balls, produced in a Sol‐Gel process, are resistant to slip‐rolling conditions, if large pores can be avoided.     

Modelling the effect of different sterilisation treatments on antioxidant activity and colour of carrot slices during storage

The effect of F₀ treatment time (min) and storage on the antioxidant activity and Hunter colour parameters (L*, a*, b*) of carrot slices was investigated. Carrot slices were sterilised for 0 (control), 3, 15 and 50 min and subsequently stored for 0, 3 and 6 months. Significant differences were observed in colour values of carrot slices with no significant difference beyond F₀ treatment of 3 min. Regression modelling was used to investigate the main effects of treatment time and storage. Treatment time and storage period was found to be significant. Predicted models were found to be significant (p < 0.05) with low standard error and high coefficients of determination (R²). This study proposes the predicted models for quality parameters of sterilised carrot slices.