Effect of using disposable polyethylene bag as a probe cover or finger cover in pulse oximetry

Background:

Consumer-grade pulse oximeters are used to monitor blood oxygen levels (SpO₂) at home. Sharing a pulse oximeter with family members in isolation centers or home isolation due to COVID-19 may increase the chances of cross-infection.

Aim:

We aimed to find if using commonly available disposable polyethylene covers either on the finger and/or on the pulse oximeter provides the same reading of SpO₂ or not.

Methods:

Two operators measured SpO₂ on 10 healthy subjects with three randomly selected pulse oximeters. Six types of commonly available polythene bags (transparent, translucent, and opaque) were used to cover the fingers and/or device. After measuring the baseline SpO₂ (i.e., without using covers), the measurements were taken with a covered finger, and/or covered oximeter probe.

Results:

The mean age of the research participants (five male, five female) was 23.9 ± 5.11 years. Perfusion index was 9.12 ± 1.63 (males 9.6 ± 1.42, females 8.64 ± 1.85, P = 0.38). Black opaque polyethylene bag as finger or probe cover did not detect any signal. There was no difference in SpO₂ reading when a pulse oximeter probe is covered, and/or a finger is covered. There was excellent inter-observer and inter-device agreement.

Conclusion:

Commonly available transparent and translucent polyethylene plastic bags may be used as finger or pulse oximeter cover without compromising the SpO₂ reading. However, an opaque black plastic bag is not suitable for finger or probe cover. These easily available and cheap pulse oximeter covers may be used by multiple patients or family members in an emergency like the COVID-19 pandemic with the potential to prevent cross-infection.

Plastic cutting boards as a source of microplastics in meat

Plastic cutting boards were found to be the source of polythene microplastic contamination in cut meat commercially available at butchers and a supermarket chain in the Middle East, making them also a direct source of microplastic in wastewater. The mean size of the microplastic in the raw meat was 1279.2 ± 835.0 µm, but decreased when the meat was cooked or fried. The microplastic melted during both cooking and frying processes and recrystallised partially upon cooling. Washing the meat for a short time (10 seconds) before preparing it reduced the microplastic contamination insignificantly, and only extensive washing of the meat over longer periods of time (3 min) helped decrease the microplastic count to 0.07 MP/g meat. The composition of the cutting boards was analysed by FT-IR spectroscopy, differential scanning calorimetry and subjected to wear, tensile and hardness tests. From a 3D photo of a spent cutting board, it was calculatedthat 875 g polythene was lost from the cutting board at the end of its lifetime.

Mycofloral profile and the radiation sensitivity (D10 values) of solar dried and gamma irradiated Pleurotus ostreatus (Jacq.Ex. Fr.) Kummer fruitbodies stored in two different packaging materials

The presence of fungi in our foods poses serious health risks as some genera of fungi may produce certain mycotoxins which have carcinogenic, mutagenic, teratogenic, and immunosuppressive effect on humans and animals alike. Fruitbodies of Pleurotus ostreatus were solar dried at a moisture content of 12.5 ± 0.2% and stored in polythene and polypropylene packs, gamma irradiated at doses of 0 (control), 1, 2, 3, 4, and 5 kGy at a dose rate of 1.7 kGy/hr from a Cobalt 60 source (SLL, 515, Hungary) and stored at room temperature 28-30°C for a period of 12 months. Mycological analyses were done at intervals of 0, 3, 6, and 12 months. A total of eleven (11) fungi belonging to eight fungal genera were isolated on both Cooke's and DRBC media; Aspergillus (A. niger, A. flavus, A. fumigatus, A. tamarii), Rhizopus (R. oligosporus), Mucor (M. racemosus), Fusarium (F. oxysporum), Penicillium (Penicillium sp.), Trichoderma (T. viride), and Rhodotorula sp. were recorded. There was a significant (p < .05) reduction in initial mycofloral population by an average of 2.2 log cycles as well as in species numbers with increasing doses of radiation. Radiation sensitivity (D₁₀ values) also ranged between 1.68-2.78 kGy. Gamma irradiation treatment is one way which can enhance food safety through the reduction in potential pathogens and has been recommended as part of a comprehensive program to enhance food safety.