Monday 26 December 2022

Big diversity of fungi residing in hand-washing sink drains

                        Image by Lars Klintwall Malmqvist - Own work, Public Domain,

Sinks and P-traps contain fungi. This is established, but the high numbers and diversity of fungal organisms is an under-researched area.


Research from the University of Reading examined 250 restroom sinks for fungi, recovering black moulds, and relatives of baker's yeast. Each of the sinks had a very similar community of yeasts and moulds, showing that sinks in use in public environments share a role as reservoirs of fungal organisms.


For most people, this isn't a problem, but for those who are immunocompromised, certain fungal species can cause serious infections and it may be prudent for some people to avoid infections by some of the opportunistic pathogens that may be lurking in sinks, such as species of Fusarium.



Some species may cause a range of opportunistic infections in humans. In people with normal immune systems, fusarial infections may occur in the nails (onychomycosis) and in the cornea (keratomycosis or mycotic keratitis).


In humans whose immune systems are weakened in a particular way, (neutropenia, due to a very low neutrophils count), aggressive fusarial infections penetrating the entire body and bloodstream (disseminated infections) may be caused by members of the Fusarium solani complex, Fusarium oxysporum, Fusarium verticillioides, and Fusarium proliferatum.


The types of fungi that live in sinks can tolerate high temperatures, low pH (acidic), and low nutrients. Some will even use detergents, found in soap, as a source of carbon-rich food. Overall, they thrive in the warm and wet environments.


There was no significant observed between male and female restrooms. The 250 sinks tested, all had a very similar population of fungi present.


The implications from the research are that better cleaning protocols need to be developed to address the colonisation of sinks and P-traps, particularly in environments where many people will use a single sink.


A p-trap is a u-shaped bend in the waste pipe that connects a sink’s drain to a home septic tank or to a municipal sewer system. Under normal circumstances, p-traps always contain some water, hence this region of the sink is a major reservoir of microbial contamination.


See: “Mycobial community assemblages in sink drains across a university campus”, published in the journal  Environmental DNA.


Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

Saturday 24 December 2022

Season's greetings


Season's greetings to readers of Pharmaceutical Microbiology Resources and of my LinkedIn and Facebook sites. Thank you for supporting my channels and for engaging in the world of pharmaceutical microbiology.

There will be lots of new content in 2023.

Meanwhile, here are some interesting and thematically appropriate images!

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (

Wednesday 21 December 2022

How To Test A Fume Hood’s Face Velocity?


What is a fume hood face?

The face of a fume hood is the plane between the bottom of the sash and the work surface. The hood pulls air from the laboratory into the fume hood through this opening. It also serves as the entry point to the work area.

By Darren DeYoung

What is face velocity?

Face velocity is the measured speed of air flowing into the fume hood's face, measured in feet per minute (FPM). The recommended face velocity for fume hoods is 100 FPM. But, it's best to check with local safety regulations because it can vary by state and use.


Face velocity is dependent on the amount of air going through the hood and size of the opening.  Fume hoods pull air through via a blower, creating a negative pressurized environment. The more air pulled through a hood’s opening, the faster the air will travel.


If face velocities are too high, air turbulence will occur between the fume hood’s face and the user. This is inefficient and will result in high energy costs as you exhaust large amounts of air from the room.


If the face velocity is too low, chemical fumes can escape the hood into the lab. This is, of course, dangerous for those around the hood.

Face Velocity Requirements

Different fume hoods can operate at different face velocities. Specific face velocities depend on several variables. The recommended face velocity is set by a safety officer or a local code. A traditional hood should be between 60 and 100 FPM. This may increase to 120 FPM if you’re working with toxic chemicals.

Variable air velocity (VAV) hoods take energy efficiency into account. When the sash is all the way open, the face velocity should be at 100 FPM. But, when you close the sash, the hood will conserve energy with less airflow. The face velocity of VAV hoods only gets as low as 60 FPM.

Testing Face Velocity

The face velocity test measures the speed of the airflow within a fume hood. Although face velocity is an adequate measure of performance, it isn’t the be-all and end-all. Many labs use face velocity as the only standard, but it only measures one aspect of hood performance. Face velocity is the only test required by most orgs, so it's often the only one performed. But, other tests can provide a better measurement of a hood’s ability to contain hazards. Many hoods meet face velocity requirements but are not able to pass air-flow and tracer gas tests. As with many situations, ensuring total safety is more complicated than a single test.


A digital anemometer is a testing tool consisting of a probe with a fan on the end. The probe measures airflow at different areas of the hood. For a fume hood to pass, its face velocity must be between 95-130 FPM.


To calculate average velocity, start by dividing the face into an imaginary grid. Each square of the grid should be approximately 1 square foot. Then, use the digital anemometer to take measurements at the center point of each square. Repeat until you have measured all squares. Then, analyze the measurements and look for outliers.


If any measurement is 20% over or under the standard then you may have a problem. Such readings state the possibility of turbulent or non laminar airflow.


A laboratory can save a significant amount of energy if the hood can operate lower than 100 FPM. But, you must supply enough air to your lab to allow the hood to exhaust at its set volume. Otherwise the hood will create a vacuum within the lab. Not all hoods can operate at 60 FPM to relieve strain on an HVAC system.

ASHRAE 110 Test

The ASHRAE 110 Method is the industry testing standard.  This test ensures that the face velocity meets the requirements.


This process goes beyond measuring the performance of a hood by its face velocity rating. It also tests the hood’s ability to contain and exhaust fumes.


The three-part test includes:

• Face velocity measurements

• Smoke visualization

• Tracer gas containment


Fume hoods are first tested after they're manufactured (AM) to ensure that they work. This occurs in a controlled testing lab.


After installing a new fume hood, you should test it in two operating conditions; as installed (AI) and as used (AU).


The AI test occurs when the hood is empty and in its final location. This test ensures that the ventilation system works, but isn't tested with any fumes.


The AU test occurs after the hood has been in use by the customer. The equipment and tools remain in the hood and activities in the laboratory continue.


While the AM test takes place in a controlled lab, the AI and AU tests happen in real environments.

Diffuser Check

Diffusers supply air to laboratories. These devices make up for the air that is being exhausted out of the building. If air currents from the diffusers reach the face of the hood, they can cause fumes to blow into the lab. Make sure to balance and replace diffusers if velocities become too high.

Foot Traffic Analysis

Ensure that foot traffic isn't directed in front of the hood. This is important if the face velocity is on the lower end of the acceptable FPM range. The average human produces a vortex of air behind them as they walk. This vortex can pull fumes out from the hood into the laboratory.

Assessing Face Velocity Results

In a standard hood, it is unlikely that velocities below 0.4 m/s are able to contain contaminants. In special situations, some fume hoods can operate at low face velocities.


When fume hoods have face velocities outside the recommended value, you must fix it.


The following conditions can cause insufficient airflow:

     Inrush of air into the room through a door or an open window

     Ventilation system imbalance

     Bulky equipment


The speed at which air enters a fume hood determines the effectiveness. A speed that is too high or low can compromise the performance of the hood.

How often do hoods need face velocity testing?

Conduct face velocity testing every three months, according to OSHA standards.


Pharmaceutical Microbiology Resources (

Tuesday 20 December 2022

Preparing for Flu Season: 3 Essential Safety Measures for Pharmacies


With flu season right around the corner, pharmacies everywhere are taking extra precautions to ensure their customers stay safe and healthy. While no one wants to get sick, it’s important that pharmacy owners take the necessary steps to prevent a potential outbreak in their store. From implementing new sanitation methods to creating social distancing policies, there are several measures that you can take to keep your store and its customers safe during flu season.


Sanitization Protocols

One of the most critical aspects of staying healthy is keeping your store clean and sanitary. During flu season, it’s even more important to be vigilant about sanitation protocols. Make sure that all surfaces, such as countertops and doorknobs, are constantly cleaned with a disinfectant cleaner throughout the day. It’s also important to use hand sanitizer at regular intervals so that germs don't spread from person-to-person contact.

By Lizzie Weakley

Social Distancing Policies

Another important thing you can do is implement social distancing protocols in your store. This means setting up barriers between customers who are standing in line or limiting the number of people who can be inside your pharmacy at any given time. Setting up signs or markers on the ground can help remind customers of proper social distancing habits while they're shopping. It's also a good idea to have signage around your store that encourages people to wear masks and practice good hygiene while they're visiting your shop.  Additionally, you might consider putting up a transparent shield between the customer and cashier. These can easily be customized by using acrylic printing services.


Encourage Vaccinations

Finally, it’s essential that you encourage everyone in your community to get vaccinated against the flu if they haven't already done so. Many pharmacies offer both traditional shots and nasal sprays for those who prefer not to receive a needle injection. By offering vaccinations at an affordable price (or free if possible), you can help protect those around you from getting sick this upcoming flu season. 


As winter quickly approaches, pharmacy owners need to be prepared for what could potentially be an incredibly difficult flu season due to COVID-19. Fortunately, there are several measures you can take—from implementing new sanitation protocols to encouraging vaccinations—that will help keep your store and its customers safe during this trying time. By following these tips, you'll be well on your way towards providing a safe environment for everyone visiting your pharmacy this upcoming winter season!


Pharmaceutical Microbiology Resources (

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