Thursday, December 27, 2018

McDonald's screen of death. I remain unsurprised.

A recent post from IFLScience.com 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 https://metro.co.uk/2018/11/28/poo-found-on-every-mcdonalds-touchscreen-tested-8178486/).   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.

Tuesday, October 9, 2018

13,000 beef animals just went to the landfill

I hope that caught your attention.  I suppose you could argue that it was clickbait.  The animals didn't literally walk to the landfill, but 6.9 million pounds of ground beef were recalled last week by a company called JBS because of fears that the meat was contaminated by Salmonella enterica serotype Newport (otherwise known as S. Newport).

There is a really good article on this recall by Joe Fassler in The New Food Economy.

FSIS was notified of a salmonellosis outbreak on 5th September 2018 and subsequent traceback indicated that JBS was the common source.  By 6th September, 57 patients in 16 states were identified as having Salmonellosis.  The strain of S. Newport in this outbreak is being reported as being multiple antibiotic resistant, though, as far as I am aware, this reporting is based on previous outbreaks.  Antibiotics are not normally used in treatment of human salmonellosis.   Experts have also pointed out that cattle are the most common source of S. Newport.

As with many large outbreaks, the situtation is at best muddy.  In general, Salmonella is found much less frequently in cattle herds than in chicken flocks.  It is not considered an adulterant by the regulators.  In some herds, the incidence of Salmonella  is zero; in others it has been found at up to 53%.  Salmonella enters the meat as a result of faecal contamination, from the animals or from the processing equipment.  Processors are not required to test for Salmonella, so JBS would not have been aware of its presence in its products.  Dairy cattle are not bred for meat production, but sick, low yielding cows are often culled and sent to meat works, where the meat, not being primal cuts, is ground and used with other meat in burger patties.  Thus, the potentially contaminated meat is spread extensively throughout the production.  You might argue that the company should test its products for Salmonella even though this is not a requirement.  However, microbiological testing is actually unreliable as a food safety control, mainly because of the problem of getting a meaningful sample from the food, particularly if the contamination is at a low level.

Since the processors are not required to test for Salmonella, they cannot be compelled to recall the potentially contaminated product, but JBS has done this voluntarily.  Well done!

However, several questions remain: why was this meat implicated in causing salmonellosis?  There are probably many answers to this.  Americans like their hamburgers rare or medium rare.  USDA raised the minimum temperature for cooked hamburgers to 160 degrees Farenheit (71.1 degrees Celsius).  Provided that this internal temperature is reached, Salmonella will be killed.  But kitchen hygiene is also critical.  If raw hamburger patties or mince are handled, cross contamination to other equipment, surfaces and foods can occur.  (Think next time you barbeque meat patties: did your utensils contact the raw meat and then the cooked meat?  I once attended a Korean BBQ where raw meat was put on a plate and then cooked before being put back onto the same plate!)   Was the processing equipment thoroughly washed down and sanitised after each shift, or is there a possibiliy that the bacteria had colonised the plant, allowing continuous inoculation of the product?  Certain designs of equipment are notorious for being very difficult to clean and providing niches for colonisation.

A more general and worrying question:  S. Newport is most commonly found in cattle and antibiotics are not normally used in treatment of human salmonellosis.  Why are we finding multiple antibiotic resistant S. Newport strains?

Take-home message:  treat all meat as potentially contaminated with pathogens like Salmonella.  Handle it carefully and cook it properly.

Monday, August 20, 2018

Wines by modern Prometheus?

I recently read an article entitled 'Frankenstein wine' warning over French supergrapes.

Apparently, French wine scientists have developed some vines that are impervious to fungal attack, specifically downy mildew and powdery mildew, and therefore requiring little or no fungicidal chemicals.  You'd think that this was a good thing and would be welcomed.  But no, some people, who may have a vested interest in turning back innovation, are claiming that the "lab-grown creations" combine genes from around the world and could lead to dumbed-down, low-grade "Frankenstein wine", whatever the hell that means.  The implication is that the new varieties are somehow unnatural.  As far as I can tell, genetic engineering has not been involved; conventional cross breeding has been used.

Let's just step back from this hysterical attack on scientific improvement in winemaking.  As a result of claimed cancer links among grape growers, the French are under intense pressure to reduce the amount of fungicides used.  The use of these new varieties would therefore seem to be a good move.  However, a winemaker and researcher from western France has claimed that these vines, which are  hybrids, would lead to "artificial and unnatural 'Frankenstein wine'."  According to the article, he likened the development of the new vines to crossing a monkey with a man - technically feasible but going against nature. That is a completely over-the-top reaction, but I'd be keen to see the resulting animal!

The development and growing of hybrid grape varieties has in fact been going on since the 1950s in the northeast and Pacific Northwest of North America.  Those varieties have enabled production of wines in these short season, cooler and more humid areas.  They also have greater resistance to disease and therefore require less use of chemicals.

Though rare, natural interspecific hybrids do occur as a result of cross-pollination, the earliest known was discovered in 1740 near a vineyard planted in Vitis vinifera.

Tuesday, August 7, 2018

FDA issues an update statement on Yuma E coli outbreak

Earlier this year, a serious multi-state outbreak of Escherichia coli O157:H7 infection was associated with consumption of Romaine lettuce from Yuma, Arizona.

The US FDA has now issued an update statement, though the investigation is not completed.  Tests of canal water close to the lettuce growing farms has tested positive for the outbreak strain of E. coli O157:H7, which is capable of producing Shigatoxin.  Infection with this microorganism can result in serious disease - 210 people in 36 states have become ill, with 96 hospitalizations and five deaths.

No single farm has been determined as the source of the outbreak, nor has the distribution chain been implicated so far.

The lettuce growing farms and canal are close to a Concentrated Animal Feeding Operation (CAFO), which can hold in excess of 100,000 head of cattle at any one time.   Since cattle can harbour the STEC E. coli involved in the outbreak, there is the possibility that the presence of the bacteria in the canal water originated from the CAFO.  Further testing of the CAFO and the animals would be necessary to establish a link.

The means by which the lettuces became contaminated must also be investigated.  Was the canal water used directly for irrigation, or were the bacteria somehow transferred from the canal water to the leaves?

Thursday, August 2, 2018

Safe Food - Product Lifetime of the blog

All products have a lifetime, after which sales drop off.  The usual response is either to discontinue the line, or to set the New Product Developers (NPD) to updating the product.  Think of ice cream.  There will probably always be a market for ice cream, but the flavours of your childhood have been surpassed and the presentation has changed dramatically.  You now have the options of ice creams on sticks, with creamy toffee, chocolate or fruit puree centres, coated in chocolate and nuts etc.

Safe Food first appeared in November 2006 while I was working at Hong Kong University.  The wide varieties of foods in HK are completely different from those of our adopted country, New Zealand, though the safety issues are similar.  I felt the need to write about the hazards associated with foods to help ordinary folk and food manufacturers to understand food safety, with the aim of reducing the incidence of food-mediated illness. I hoped the blog would become a resource for teachers in schools.

I have no idea whether these lofty aims were successful!  The blog has only 10 followers 😢 but in the 12 years I have been writing it, there have been nearly 348,000 page views, so I guess that means that some people have found it useful.



Very few people have left comments on the blog, though some have contacted me directly - usually young mothers who have had food scares with their babies and young children.

There are only so many unique food safety incidents to report on.  Often contamination and recalls merely reflect the sad fact that manufacturers, distributors and consumers don't learn from earlier incidents.  This is one of the reasons that Safe Food has not been published so frequently in the years since I retired from full time teaching and research.  Perhaps the blog has become stale and "same old, same old".

It's time for some NPD!  I have decided to continue writing the blog, but I want to widen the scope just a bit so that I can comment on some of the food myths that are now so frequently proliferated by minor celebrities, fanatics and those who can best be described as "loonies".  There are exciting new developments in foods, such as the plant-based milk and meat substitutes, most recently exemplified by Air New Zealand's offering The Impossible Burger on some of its flights, and I want to discuss these evolutions in food supply.

I may also update the appearance of the blog, so, watch this space and please consider bookmarking, as the option for e-mail following is to be removed by Google in July 2021.


Wednesday, August 1, 2018

I've been served some pretty awfull coffee in my time ...

Many people on Twitter are reporting that a pregnant woman in Alberta ordered a latte at a McDonald's but was served a cup containing cleaning fluid.

According to a report on CBC News, this was caused by the coffee machine still being connected to two cleaning solution supply lines, rather than the milk reservoir.  The cleaning chemical was a mixture of citric acid, phosphoric acid, methyl-trimethyl-3, and 2-butoxyethanol.  There is no doubt that ingestion of this material would be harmful.

It's not clear whether the cup contained hot liquid, though if the machine were set to deliver coffee, but connected to a cleaning chemical supply, it's likely that the cup did feel normal, and since it was a takeaway, it would have been fitted with a lid, so gave no indication that it didn't contain latte.

This potentially very dangerous incident gives a lesson:  if you are a pilot, a car driver, or the operator of a food processing machine, the principles are pretty much the same - the pre-start checks must always be conducted before any start and done properly.

Sunday, June 3, 2018

E. coli strikes again

Five people in the United States have died since March and approximately 200 are sick as a result of an Escherichia coli infection apparently acquired from romaine lettuces grown in the Yuma region of Arizona.  However, the authorities have been unable to pinpoint the source of the contamination.

Though E. coli are found in the gut of man and animals, only certain strains cause serious illness.  These strains have assembled many genes that enable them to attach to the cells lining the intestine and produce very damaging toxins called Shigatoxins.  This is an example of the continuous evolution of bacteria.  Many of these new strains are the result of bacteriophage infection transferring genes between bacteria or possibly by direct transfer between strains.

Various posts responding to news reports of the outbreak have suggested washing the lettuces as a means of preventing illness.  Unfortunately, washing, even in chlorinated water, will not guarantee removal of the bacteria, as they can attach to the lettuce or even localise in the stomata of the leaves.  I obtained the following image from https://www.inverse.com/article/28938-e-coli-detection-lettuce-feces.





You can see bacteria within the stoma; it is clear that they would be very difficult to wash out.

This outbreak was originally thought to be caused by bagged and chopped lettuce, but inmates in a prison in Alaska also became ill after eating whole head lettuce.  In view of these facts, it is unfortunate that consumer advocates are urging the FDA to introduce new rules to speed up investigation of such outbreaks.  It is hard to see how new rules would influence the investigations, given that it has so far been impossible to tie the contamination to a single farm, processor or distributor.

The one fairly sure conclusion is that the lettuces have become contaminated with faeces, since this E. coli is not a natural inhabitant of the environment.

Wednesday, March 28, 2018

On the turps - it's insane.

In New Zealand where I live, we have a phrase "On the turps".  It means "drinking alcohol" usually, but not always, beer.  When you've been on the turps, you may have a hangover if you were serious about it.

I have a thing about ill-informed food and drink advice, some of which is downright dangerous.  Totally unqualified people seem to think that they can hand out advice on diet, so-called "super foods" and other health issues.

The latest whacky outpouring from a minor celebrity suggests that drinking a small quantity of turpentine with sugar will rid you of a cold overnight.  This is a BAD IDEA.

Turpentine is prepared from the resin of pine trees and, I have to say, smells really nice and fresh.  I used it when I was painting in oils to thin the paint.  Another person giving the advice, this time a disbarred doctor,  claims that her IQ "went up like 50 points".  I think she has the sign wrong - it should be -50 points.

There is plenty of scientific evidence to show that turpentine is poisonous, causing irritation to the eyes and central nervous system and severe damage to the kidneys, or, in sufficient quantities, death.

We have been considering natural turpentine here.  Hardware stores sell "mineral turps" which is a turpentine substitute prepared from petroleum.  Consumption of mineral turps may not be fatal, but can result in lung damage and irreversible brain damage.

Of course, this post is not strictly about food safety, but I believe it is important to get this message out there.

I feel so strongly about misleading food and nutrition advice that I am chairing a conference in New Zealand with the theme "In food we trust: confidence built on science and technology".

Monday, March 26, 2018

A useful Sanitation Checklist.

This checklist was sent to me by Meyer Industrial Solutions.  I have provided it for the benefit of readers, without endorsement of the company.

There are a couple of things that I think merit comment:

  • Step 1.  The use of compressed air to move residues may have the effect of spreading them around the processing area.  Better to manually sweep.
  • Step 2.  If the equipment is contaminated with proteinaceous material, I recommend using warm water for the intial rinse.  Hot water may set the protein and make it more difficult to remove.
  • Step 3.  I agree that the use of pressurised water for rinsing tends to spread contamination around.  I once visited a meat processing facility and found meat scraps on the ceiling, put there by pressurised water!

This was created by Meyer Industrial

Friday, March 9, 2018

Raw milk comments cause another minor furore

This time, a senior scientist has kicked over the beehive and created a minor furore.   Professor Nigel French FRS, Director of the New Zealand Food Safety Science and Research Centre, has stated in an interview that he would not drink raw milk, nor give it to his family.

In my opinion, he is correct in stating that even the most careful production of raw milk cannot avoid some contamination by cow faeces, which, of course, contain bacteria and viruses.  Some of these bacteria and viruses can cause serious human disease.  As a microbiologist, I am fully aware of the sensitivity of microbiological testing and can confirm Prof. French's comment that bacteria can still be present, even if the test shows negative.

Scrupulous cleanliness and attention to detail can reduce the chances of faecal contamination of the milk, but cannot eliminate the risk.  Since the beginning of the year, there have been two recalls of raw milk over fears of contamination by Campylobacter, a bacterium that can cause diarrhoea (frequently bloody), abdominal pain, fever, headache, nausea, and/or vomiting.  Occasionally, it can produce more serious symptoms requiring hospitalisation.

Reading the comments on the article, it is clear that the proponents of raw milk consumption will not be swayed by scientific facts, and it is their right to drink raw milk.  However, the New Zealand
Prime Minister's Chief Science Advisor Dr Peter Gluckman concluded: "The claimed health benefits of raw milk compared with pasteurised milk are for the most part not backed by scientific evidence, making the risk-benefit ratio very high for this food product ..."  

I have written about the hazards of drinking raw milk before (see the label Raw Milk) and the latest recalls simply confirm my opinion.  Many of the people commenting on the report are saying that they grew up drinking raw milk without problems.  What they appear not to appreciate is that our lifestyle has changed.  We don't collect our milk daily; children are coddled and protected from exposure to bacteria by the use of antibacterial soaps and cleansers, they don't go out to play in the dirt and often they are not exposed to farm animals.  In my opinion, their immune systems are less robust.  At the very least, children should not be fed raw milk - they have no ability to refuse it.  

The regulations surrounding sale of raw milk have been tightened considerably, including labelling and warnings on bottles.  Raw milk cannot be sold from health food stores and use-by dates must be printed on the packaging.  It is interesting to note that sales of raw milk are not permitted in Australia.

Sunday, January 7, 2018

Wild meat and botulism - update.

As I suggested in the original post, the tests on food and other samples have now shown that the poisoning of the family in New Zealand, apparently caused by Clostridium botulinum, was not caused by botulin toxin. However, no other explanation for the families symptoms is forthcoming. Conspiracy theorists are suggesting the boar had consumed 1080 poison (used for possum control) but there is no evidence for this. Many other toxins could be involved - fungal or plant toxins, or even toxins in spices brought from India by a relative of the family. Chances are we will never discover the cause in this case. However, reading the increasingly confusing reports around the case does raise concerns that more extensive testing was not conducted at the time.

A further possible explanation might be provided by a Massey University PhD student's work.  Hayley Hunt of the Institute of Veterinary, Animal and Biomedical Sciences is investigating a rare disease in hunting dogs called Go Slow. The disease affects the dogs’ ability to walk by altering the mitochondria (energy-producing structures within cells), so that their muscles are no longer able to contract.  She says the likely cause of the disease is dogs eating wild pig meat that has been poisoned when the pig eats particular plants. The identity of the plant and toxin that may be tainting the pig meat is currently unknown and may be difficult to define, as there are so many possibilities.

Raw water: Is it bullshit?

There is a new fad spreading rapidly in the US.  "Raw water" is the latest craze for health fanatics keen to spend serious money.

What is raw water?  Its proponents claim it is water as nature intended it - unfiltered and untreated, containing minerals from the water source and no chlorine.  One raw water company claims that "all other bottled, filtered, tap, and even spring waters are sterilised with ozone gas, irradiated with UV light, and passed through a submicron filter" and that "blasting water with ozone changes its molecular structure".  Clearly, there is some truth in this statement, but also a lot of nonsense.

Some water sources are indeed safe to consume untreated; others may appear to be so, but are not safe.  In August 2016, over 1000 residents of Havelock North in New Zealand became ill after consuming drinking water from two bores operated by the local council.  Investigations showed that the affected residents had been infected by Campylobacter.  This was not the first time that the bore heads had been found to be contaminated.   The outcome of an extensive investigation was that the water in the bore heads was contaminated with water from an adjoining farm pond on land that had been inundated by heavy rains.  The aquifer was not contained and when the pumps were turned on, water from the pond, probably contaminated with sheep faeces, was drawn into the town supply.  Anecdotal evidence says that the level in the pond dropped when the pumps were turned on.  An immediate response was to chlorinate all water supplied in the area, which annoyed some residents, and the two affected bores were closed.  Water was drawn from other bores in the nearby Hastings area and  the supply has been chlorinated.

I am constantly surprised by people who want to turn back the clock to a time when food and water borne diseases were common, before modern scientific and technological advances made our lives much safer.  Campaigning to ban chlorination of town water is one of those issues.  Consumption of raw milk is another one of those desires that can lead to illness.

However, I am also reminded constantly that many rural areas are not serviced by mains water and wastes are treated on site in septic tanks, then discharged to the land.  Our house on our own lifestyle farm collects water from the roof and stores it in 36,000L tanks.  There is no filtration, chemical or UV treatment.  We, like many other rural dwellers, are thereby deliberately exposing ourselves to risk, though there is no alternative other than boiling water or buying bottled water for drinking.  The only thing I can say is that since moving to the farm over 30 years ago, we have never suffered from gastrointestinal illness.

Where does this leave us?  Treated tap water is probably the safest water supply.  Experience shows that rural tank water is usually safe, though it is not sterile; provided that the tanks are protected from contamination by animals or from septic tanks, there is little to fear from drinking it.  The perceived benefits of bottled raw water may be illusory, and the marketing hype criticising filtration and ultraviolet treatment of spring waters is just plain misleading.  Those getting the most benefit from bottled raw water are the suppliers.