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 following.


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.