Saturday, August 17, 2019

Can this be real?

It's amazing how a throwaway line can be picked up and takes on a life of its own.  A New Zealand botanist referred to a lichen, Xanthoparmelia scabrosa, as "Sexy Pavement Lichen" because it contains a PDE5 inhibitor.  See

It appears that powdered X. scabrosa is being sold on-line as a Viagra alternative.  It has even been reported that people are actually licking sidewalks!  This is probably not a smart way to obtain a potential erectile disfuntion medication, as the inhibitor is not the same thing as Viagra and is also somewhat toxic, not to mention the contamination of the lichen from vehicle exhaust, dust and grit etc.

According to Tom Hale, writing for IFLScience, the US FDA analysed a sample of the powder bought on-line and found it consisted of 80% Viagra and 20% grass clippings (really?)

Thursday, July 25, 2019

Listeria in smoked salmon - again.

The Department of Health in Australia is investigating three separate cases of Listeriosis apparently associated with smoked salmon.  There have been two deaths and one

This is not a reason to stop eating smoked salmon, or even cause for a massive recall.  There is a couple of things we all need to know.

Firstly, no specific smoked salmon product has been recalled.

Secondly, the three cases were in three different states and occurred over the period 22nd February to 7th June.  i.e. they were well separated both in location and time.

Thirdly, and probably most importantly, all three patients were over 70 years old and had other health conditions that may have predisposed them to infection by Listeria.

This is a reminder that people who may be susceptible to listeriosis should avoid foods that are known to carry higher risk of infection.

See:  and search the blog using keyword Listeria.

Tuesday, July 9, 2019

A caffeine fix too far

This post is a little different from many of my articles, which have been predominantly about food microbiology.

The Sydney Morning Herald is reporting the death of a young man who dosed his protein shake with caffeine powder.  

Saturday, June 22, 2019

Mussels unsafe if eaten raw

Many people in New Zealand like to eat shellfish, such as mussels, raw.  The Ministry of Health and New Zealand Food Safety Authority (Te Pou Oranga Kai O Aotearoa) has warned consumers NOT to eat fresh mussels harvested commercially in Coromandel, an area of the North Island, without cooking them to at least 65C.

The culprit for the current food poisonings is probably Vibrio parahaemolyticus, a bacterium found in marine, coastal and tidal waters, and most commonly causes gastroenteritis.  It is not normally spread person to person, though poor personal hygiene, such as failure to wash hands after handling raw shellfish, could result in infections.

Symptoms usually occur within 24 hours of eating the infected food and include
  • watery diarrhoea (occasionally bloody diarrhoea)
  • abdominal cramps
  • nausea
  • vomiting
  • fever
  • headache.

Image from Pathogen Profile Dictionary

There is a feeling among some experts that Vibrio parahaemolyticus entered New Zealand in imported fish or shellfish.  Cross contamination in the markets then allowed its spread.

Wednesday, May 1, 2019

Helpful Guide to Food Safety and Kitchen Clean-up - guest column

As most readers know, I normally don't post comments that contain links to commercial sites.  I get quite of lot of these, and in most cases, the writers are just trying to get clicks on their own sites.

However, occasionally a message comes along with useful information.   I received an invitation recently to publish a guide to food safety and kitchen clean-up.  This came from Cleaning Building Services New York.

A Guide to Food Safety and Kitchen Clean Up

An essential part of preparing a meal is making sure to use the proper food safety techniques. Without proper safety protocols your food can become contaminated and pass along foodborne illnesses to whomever eats or comes in contact with it. The Centers for Disease Control and Prevention (CDC) states that 48 million Americans become sick from foodborne illnesses each year. Of those 48 million people, 128,000 are so sick that they need to be hospitalized, and 3,000 people even die from the foodborne illness. To prevent foodborne illness from happening to you or your family, it is important to practice food safety protocols while handling, preparing, and storing all of your meals.

Cleaning Up the Kitchen

Keeping your kitchen clean is an important step in food safety. After each meal, it is important to clean and sanitize all surfaces where food was prepared or handled. All surfaces should be washed thoroughly with hot water and soap. For a deeper clean the surfaces can even be washed with a diluted chemical mixture of 1 tablespoon bleach and one gallon of water. All cooking appliances used when preparing the meal should also be washed thoroughly inside and out. An important step that most people tend to forget about is cleaning out your refrigerator. You should be going through your refrigerator once a week to discard any expired items to prevent growing bacteria. Vegetables and Fruits should also be rinsed under water before being consumed to get rid of any pesticide residue. You should always clean your hands thoroughly after touching any raw meats or fish as well, this will help prevent transporting harmful bacteria.

Know Your Temps

Foodborne Illness is caused by harmful bacteria, some of the most common being Escherichia coli, Salmonella, and Staphylococcus. This harmful bacteria can be consumed by eating undercooked foods and can be prevented by making sure all food is being cooked to their accurate internal temperatures. This can be done by using a kitchen thermometer. Checking the internal temperature is especially important when preparing foods like meats, fish, poultry, and eggs. Before preparing a new recipe, be sure to research what temperatures your ingredients should be kept at to avoid them being in a danger zone for the harmful bacteria.

Food Organization

When buying food at the grocery store, look for broken seals and damaged containers before putting them in the cart. Also, be sure to check expiration or sell by dates to only purchase fresh and safe to eat foods. When cashing out in the register line, be sure that your meat or fish is packaged separately to avoid juices spreading onto your other foods. Separation is key when storing your foods away at home as well. You should always store raw meat or seafood below any other foods in your refrigerator and place them in plastic bags to avoid contamination. If possible, use different cutting boards and other cooking utensils for meats or fish and veggies. If not, be sure to clean them thoroughly in between each use. Doing this will lessen the chances of leftover bacteria being transported from your raw meats or fish to your cut veggies and fruits.
Other material from this source will appear on this blog from time to time.

Declaration:  Safe Food Blog does not endorse Cleaning Building Services, not does it have any pecuniary interest in the company.

Thursday, December 27, 2018

McDonald's screen of death. I remain unsurprised.

A recent post from claims that microbiologists from London Metropolitan University conducted swabbing on touch screens in McDonald's restaurants in London and Birmingham, finding coliforms, Bacillus and Listeria.  They also found Staphylococcus, PseudomonasEnterococcus faecalis and Klebsiella.

All of these bacteria are capably of causing infections, and you will find some discussion of these bacteria on this blog site - see labels.

But should we be surprised and should customers at McDonald's be concerned?  Well, I am not at all suprised.  If a microbiologist conducts swabbing in any public place, such as a supermarket, they will find all of these bacteria, perhaps on trolley handles, push plates on doors, in the toilets etc.  As for the customers, if they are concerned, they could order their meal on the touch screen, then wash their hands, or use a hand sanitiser.  Be honest - if you go to any fast food joint after you have been shopping in the mall, do you always wash your hands before you eat?

The original research was done for Metro (see   Not surprisingly, when this post was published on FaceBook, there were 1.2 thousand comments and nearly a thousand shares.  My personal opinion is that this article was written and published for shock value and to boost circulation.  Interestingly, a video clip posted on this same site showed that the majority of customers were not surprised by the findings and would still go and purchase food there.

Whatever you think of McDonald's or any other fast food outlet, in my opinion, the researchers are making a mountain out of a molehill, and IFLScience is making it worse.  Don't pick on just one fast food chain, and think about how you protect yourself and your family from infection.

And while you are at it, think about a similar scenario in your own home.

Food for thought:  How do you recognise the microbiologists around you?  They are the people who use their little fingers or elbows to open doors, use a paper towel to turn the taps off in a public washbasin, use a knuckle on the touch screen and who often use hand sanitiser before eating in public.

Monday, November 5, 2018

Downside of reusable shopping bags?

Supermarkets in New Zealand are discontinuing the use of single-use plastic bags as a contribution to reducing plastic pollution.  (My personal view is that this is just scratching the surface of the problem - produce is still wrapped in plastic and just about everything we buy in the line of detergents, shampoos, hand creams, water etc. is packed in plastic).

Some supermarkets are offering free or very inexpensive fabric bags to carry home the purchases.

A New Zealand politician has jumped on this, quoting a discredited overseas study that suggests that the use of reusable fabric bags will result in some deaths from food poisoning.

The general opinion among experts, myself included, is that this is silly scaremongering.  If meat and poultry is carried in these bags and blood or drip escapes the packaging, then the bag will be contaminated.  If unwrapped salads, cured meats, cakes, pastries and bread are carried in the same bag, cross contamination may occur.

Just as in the kitchen, it is sensible to separate raw meats, which will be cooked, from foods that will be consumed without further cooking.  Different chopping boards should be used for raw and cooked foods, and fabric bags used for raw meats should be washed regularly.  This not rocket science.

Others have jumped on the bandwaggon, once again putting forward the suggestion that sale of raw chicken, which often contains Campylobacter, should be banned in favour of frozen products.  Certainly, freezing reduces the numbers of Campylobacter, but does not eliminate it.

It seems to me that a slight change in mindset is required, together with a greater understanding of food hygiene.