The Mayo Clinic

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Don says:

"I had the wonderful privilege of touring Mullins Food Products, Makers of mayonnaise.. "(Mayonnaise) doesn't even have to be refrigerated. No harm in refrigerating it, but it's not really necessary." He (the food chemist) explained that the pH in mayonnaise is set at a point that bacteria could not survive in that environment.

(The food chemist) says that when food poisoning is reported, the first thing the officials look for is when the 'victim' last ate ONIONS and where those onions came from (in the potato salad?). Ed says it's not the mayonnaise (as long as it's not homemade Mayo) that spoils in the outdoors. It's probably the onions, and if not the onions, it's the POTATOES.

He explained, onions are a huge magnet for bacteria, especially uncooked onions. You should never plan to keep a portion of a sliced onion. He says it's not even safe if you put it in a zip-lock bag and put it in your refrigerator. "

Ye gods! Where do I start?

The easy bit first: see a previous post on the myth of onions being bacteria magnets. Make sure you read the comments, as the saga went on for a while.

Secondly, there is a popular myth (only in the US for some reason) that mayonnaise is a chief culprit in food poisonings. It isn't. Or at least commercial mayonnaise isn't, as it is made in strictly controlled conditions.

1. The pH of mayonnaise is kept low, at a level that bacteria cannot survive.
2. The water activity of mayonnaise is low, meaning that the moisture present in the mayonnaise is not available to the bacteria (or mould) to use and
3. the product is made in sterile conditions.

The consequences of that last item eludes many people. They think that bacteria just happen. That is as sensible as watching a field, hoping for corn to grow. If you don't plant it, it wont grow.

And "if not the onions, then the potatoes"?

Anything that grows in dirt can have bacteria on it. It will be in an environment where there is E-coli, Salmonella, Clostridium, lots of bugs with long and threatening names. Wherever birds poop and animals roam will have bacteria. You meet up with them every day of your life. And survive.

But if you take some potatoes and cook them there will be no bacteria alive on them.

Put them in a potato salad with mayonnaise and they will still have no bacteria on them.

The biggest problem is when you add bacteria to the salad yourself and then leave the salad sitting unrefrigerated for hours on end. At room temperature bacteria multiply tenfold an hour.

So where do these bacteria come from? Spices, raw unwashed vegetables and, most commonly, poor personal hygiene when preparing the food.

But from the mayonnaise? No.

From onions? No.

From cooked potatoes? No.
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Of camels and straws and chocolate

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Really, the picture is just there because it is pretty.

This post has nothing to do about camels, a little to do about straws of the sort that worry camels but nothing to do with drinking straws but a little to do with chocolate.

But most to do with dieting and perspective.

Many moons ago we had a receptionist who seemed, like most women, to be on a permanent diet. To reward herself for her calorific restraint she treated herself to a 50g (2oz) chocolate bar every day as part of her lunch.

50g of chocolate. Every day.

Doesn't seem much until you multiply by 365.

That's over 18 kilograms of chocolate a year. Nearly 40 pounds of fat and sugar a year.

Surely her diet would do better if she didn't eat the chocolate.
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Eating eggs in summer.

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I've been AWOL from this blog for a while. So much so that Joy Vazapully, who posted the following question, has disappeared from the blogland. I hope the eggs didn't get her.

Joy's question was: "There is a belief that one should not eat eggs in summer, do you think there is any reason?"

The short answer is no.

The longer answer is that, if they affect you in any way, don't eat them but apart from that no.

I know of no reason to be wary of eggs in summer. Obviously normal handling rules apply and you should be aware of the issue of temperature abuse and bacterial growth but that is a normal food hygiene issue and not specific to summer as such.
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Coming back for (five) seconds - The Five Second Rule

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I can't believe some people - I only recently caught up with the supposed Five Second Rule and it is just bizarre.

In essence, it says that if you drop something on the floor, you have five seconds where it is safe to pick the food up. It implies that bacteria wont hop onto the food in that time.

Sure.

Now, if it is a crisp (above) there will be minimum contact with the floor and most respectable bacteria would not worry about trying to live on a crisp anyway.

But what if it is a swab the surgeon is going to use on (in!) you in an operation? Still so sanguine?

The more sloppy the food, the more likelihood of bacteria hopping on board as it makes better contact with the floor.

But there are some provisos:

1. If the food is really sloppy it will leave a layer on the floor and there will not be much or any transfer onto the food.

2. The other issue is the one of what is known as the infectious dose. Sure some bacteria will get on the food but there will not be enough to make you sick unless you put it somewhere to grow the numbers a bit. eg too it into the salad you are making for lunch in three hours time.

3. What about interesting things like worm eggs from your dog, cat, hamster? (Erk!)

I'll drink to that!

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You are not going to want to read this: chocolate cannot be relied upon as a source of antioxidants to boost cardiovascular health. But it gets worse: drinking coffee and red wine in the hope it will prevent heart disease doesn't work either.

- The Age Newspaper.

Why am I not surprised?

Have I not said from day one (of this blog) that there are no silver bullets?

Note: I do have to be careful - the reports in the media are exactly what I expected to be the case so the temptation to be uncritical is high.

But really why should anything be a silver bullet? We, as animals, have evolved along with the plants. Some we have leant to eat safely. Some we have learnt will kill us and should be avoided. True, there may be some plants which have beneficial properties but it is pure fluke and certainly there is no reason to think that, if a little is beneficial, a lot will be more so.

Even red wine.
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Revisiting Alfalfa Sprouts

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Pythagorian asked: I read your warning about alfalfa sprouts and wonder how and what bleaching methods you recommend. Also I have read a claim that there has never been a case of sprout contamination traced to certified organic sprouts. Do you know if this is true or false?

The common commercial process is shock chlorination of the seeds and chlorination of the water.

The organic claim will be false. The main issue is you have a protein-rich food source that you are keeping wet and warm for several days. Any bacteria present will thrive. This has nothing to do with the organic status of the food, bacteria is naturally present in the environment. In some ways organic produce may have more bacteria. This is not a bad thing, just a consequence of things growing in the open.

Chlorination will kill the bacteria. Other processes might too. My observation is that there is not much margin for error. Warm and wet, bacteria will double in numbers every 20 minutes and most sprouts are eaten uncooked.

The Chinese eat lots of sprouts, without problems, but they stir-fry them and this kills the pathogens.
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Blowers vs Towels

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This is more microbiology than chemistry but it has been a subject that fascinated me. Electric hand dryers in public toilets have long been touted as more hygienic than paper towel.

Not so, it seems.

[Wikipedia] In 2008, a study was conducted by the University of Westminster, London, to compare the levels of hygiene offered by paper towels, warm air hand dryers and the more modern jet-air hand dryers .

The key findings were:

• after washing and drying hands with the warm air dryer, the total number of bacteria was found to increase on average on the finger pads by 194% and on the palms by 254%
• drying with the jet air dryer resulted in an increase on average of the total number of bacteria on the finger pads by 42% and on the palms by 15%
• after washing and drying hands with a paper towel, the total number of bacteria was reduced on average on the finger pads by up to 76% and on the palms by up to 77%.

The scientists also carried out tests to establish whether there was the potential for cross contamination of other washroom users and the washroom environment as a result of each type of drying method. They found that:

• the jet air dryer, which blows air out of the unit at claimed speeds of 400 mph, was capable of blowing micro-organisms from the hands and the unit and potentially contaminating other washroom users and the washroom environment up to 2 metres away
• use of a warm air hand dryer spread micro-organisms up to 0.25 metres from the dryer
• paper towels showed no significant spread of micro-organisms.

And, yes, the work has been replicated.
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