Importance of the Precautionary Principle With Regard to the Risk of Exposure to Aerosols Containing Viral Loads of SARS-CoV-2 Present in Feces: In Perspective.

In COVID-19 infection, the emissions of droplets and aerosols produced by the respiratory tract of contaminated subjects may represent a high risk of spreading the SARS-COV-2 virus in the environment. Thus, studies have shown that there is, at least, another source of droplets and aerosols in which viral particles of SARS-COV-2 can be found. It happens after flushing of toilet to dispose of the stools of a patient who has contracted COVID-19. The presence of viral particles of SARS-COV-2 in the stool could be linked to the concentration of angiotensin-converting enzyme 2 (ACE2) found on the surface of intestinal cells. Therefore, there is a reason to wonder whether the emission of viral particles by activating a toilet flush could represent an important potential risk of contamination for health care workers. To investigate this hypothesis, we have correlated different studies on the production of droplets and aerosols as well as the presence of viral particles following flush of toilet. This pooling of these studies led to the following conclusion: the precautionary principle should be applied with regard to the potential risk represented by viral particles of SARV-COV-2 in the stool when flushing the toilet.

Gnetum africanum: a wild food plant from the African forest with many nutritional and medicinal properties.

Gnetum africanum is a forest liana that grows abundantly in Central Africa, South America, and tropical and subtropical Asia. Its leaves are eaten as a vegetable, either raw or finely chopped and cooked; they are also widely used as an ingredient in soups and stews and are much in demand for their nutritional and therapeutic properties. In the latter application, various fractions of G. africanum are used medicinally to treat many different illnesses. Many studies have also shown that the chemical composition of the leaves of this plant gives it significant nutritional properties, and its high fiber, protein, and calorie content support these claims. Several molecular compounds related to the families of stilbenes, glycosylflavones, and flavonostilbenes have been isolated and identified in the leaf extract of this plant. These molecules give the plant its interesting properties and biological activities.

Efficacy of egg cleaning compounds on eggshells contaminated with Salmonella enterica serovar Enteritidis.

Salmonella Enteritidis infections of egg contents can be related to external contamination of the shell. In this study, the efficacy of three commercial cleaning and/or sanitizing compounds (sodium carbonate, sodium hypochlorite, and potassium hydroxide) was evaluated for bactericidal activity at pH values of 10, 11, and 12 against various concentrations (10(2), 10(4), or 10(6) CFU/ml) of Salmonella Enteritidis inoculated onto the eggshell surface. Efficacy of these chemical agents was also assessed against Salmonella Enteritidis in aqueous suspension. Our results indicated that none of the chemicals applied at the recommended manufacturer's concentrations (sodium carbonate, 36 ppm; other treatments, 200 ppm) could eliminate Salmonella Enteritidis from eggshells artificially contaminated with the highest bacterial concentrations (10(4) or 10(6) CFU/ml). Higher concentrations of each product, at least 5 to 20 times greater than recommended doses, were needed to destroy the bacteria on egg surfaces. However, at or slightly above the manufacturer's recommended use concentrations, all three formulations were effective against Salmonella Enteritidis in aqueous suspension (10(8) CFU/ml) or on eggshells contaminated with 10(2) CFU/ml. For both shell and suspension assays, inactivation of Salmonella Enteritidis occurred at lower concentrations at pH 12 than at pH 11 and 10. Contact time between chemicals and Salmonella apparently influenced bacterial inactivation. Extended contact times (2 to 10 min) reduced minimum chemical concentrations necessary to inactivate the bacteria. However, neither pH nor contact time influenced Salmonella Enteritidis inactivation when the initial bacterial numbers on eggshells were high.

Evidence for Escherichia coli O157:H7 attachment to water distribution pipe materials by scanning electron microscopy.

Scanning electron microscopy observation was used to investigate the adhesion of Escherichia coli O157:H7 on water distribution pipe surfaces such as copper and polyethylene plastic at different contact times and storage temperatures. Our results indicated that E. coli cells could easily attach to both surface types after exposures as short as 1 or 4 h at ambient (20 degrees C) and refrigeration temperatures (4 degrees C). Also, we found that copper surfaces have a higher number of attached E. coli cells than plastic surfaces. The number of cells attached to each type of material depended on the nature of the water distribution pipe surfaces and the length of contact time. In addition, the surface energy value of each surface estimated by contact angle measurements using water, alpha-bromonaphthalene, and dimethyl sulfoxide as wetting agents showed that both copper (41.2 megajoules [MJ] m(-2)) and plastic (45.8 MJ x m(-2)) have a low energy surface. In no cases could evidence of extracellular material be observed on surfaces with either exposure condition.

Attachment of Arcobacter butzleri, a new waterborne pathogen, to water distribution pipe surfaces.

The capability of Arcobacter butzleri to attach to various water distribution pipe surfaces, such as stainless steel, copper, and plastic, was evaluated using scanning electron microscopy. Our results indicated that Arcobacter cells could easily attach to all surface types and the number of attached cells depended on the length of exposure and temperatures (4 and 20 degrees C). Extracellular fibrils were also observed on the stainless steel surface, especially after 72 h of contact times at both refrigeration and ambient temperatures. In addition, the surface energy value of each material was estimated by contact angle measurements using water, alpha-bromonaphthalene, and dimethylsulfoxide. The surface energy of A. butzleri was 58.6 mJ x m(-2) and the surface energy values of the three surfaces studied showed that plastic had a low energy surface (26.1 mJ x m(-2)) as did copper (45.8 mJ x m(-2)) and stainless steel (65.7 mJ x m(-2)).