Saturday, January 14, 2012

Potomatatoes & Acidity

Anonymous asked "Do totatoes can acidity in the body?"

Well, that is not an easy question to answer, as such.

Are we talking potatoes or tomatoes?
Are we talking cancel or cause?

Never mind - I'm guessing that it relates to the much discredited acid-alkaline diet that lingers in the fringe diet circles.   In essence, it proposes that foods are good or bad depending on the pH of a solution of the ash of the food.  The notion that the acidity or alkalinity of the ash of a food will influence the impact that the food has on your body is just plain weird.

There is no scientific data to support the theory.  There is not even a coherent theory.

Your stomach is already 100-1000 times more acidic than a tomato or a potato, so any native acidity will have a negligible impact.  No foods are natively alkaline.

As you body never reduces food to its ash, the properties of the ash are immaterial to human nutrition.

Eat a varied, balanced diet.
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Wednesday, December 14, 2011

Cancer and spices.

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Anonymous asked: "Do ginger, curry powder and cumin powder help reduce risk of any cancers? "

Disclaimer:  I am a food chemist and any medical comments are those of a food chemist.
 
Will anything prevent cancer?

No, probably not.  Cancer is not one disease but a diverse group of illnesses, all characterised by uncontrolled cell growth.  Cancerous cells are being produced all the time and the body deals with them.  The problems arise when the body can no longer deal with them.  This will be partly why cancers are more prevalent in the elderly; the body’s defences get weak, lazy or ineffective.

I believe that pretty much anything will cause cancer – if the body gets swamped with any chemical, systems can go awry.

But will anything prevent cancer?   I don’t believe so.  At least not any one thing.

Good diet and good health seem to be part of the cancer preventative thing :  be healthy, give your body a chance.  Let your body function as it should, defences work properly, cell reproduction work reliably.

I have little doubt that the individual components of ginger, cumin and curry powder will trigger cancers if taken in excess.  Anything taken at a level that distresses the body increases the likelihood of the body malfunctioning and cancers being the result.

But I really have no knowledge on compounds, natural or synthetic, that may directly work to prevent cancers.  And I think it unwise to pin your hopes on a 'silver bullet'.
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Sunday, October 30, 2011

Take it with a pinch, no, a bag of salt!

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Food Australia, who should know better, published an article earlier this year titled "Contaminated reusable grocery bags pose health risks" (63 (5) - May 2011). It was based on an article by Gerba & Sinclair entitled "Assessment of the Potential for Cross Contamination of Food Products by reusable Shopping Bags". You can download the full article here.

The article suggests bacteria, including E. coli, flourish in the green bags.

And the are probably right. The same way bacteria can flourish in pretty much any environment. Because bacteria is IN the environment. If they had done their survey by swabbing the jeans of the shoppers rather than the bags, they would have got similar results.

And as for soaking the shopping bags in meat juices and leaving them in a car boot (trunk) for two hours - well, duh!, of course bacteria levels will increase.

It was all a bit odd and I had a niggling suspicion, which is why I chased down the original article rather than relying on the summary in Food Australia. My suspicion was confirmed in the following line:

"The authors would like to acknowledge and thank the American Chemistry Council for providing funding to support this study."

So, the American Chemistry Council, a body that includes all the plastic (bag) manufacturers of America in its ranks funded the research.

Doesn't mean it's wrong but there are flashing lights all over it!
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Monday, August 29, 2011

Not ducking the question.

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Celia of Fig Jam & Lime Cordial, asks

"I've been making confit duck, and keep it for a short time in the fridge.

1. As instructed, I've been reheating the used duck fat to clarify it and then storing it in the freezer to be reused next time - is this a safe practice, and how many times can the fat be reheated and reused like this, please?

2. Secondly, confit duck (a traditional food) has been stored for generations by the French on the pantry shelf, with some instructions going so far as to say "don't worry if the bones not covered in fat go a bit green". I don't do that, I keep it in the fridge, but wondered whether it was actually safe to store meat like this unrefrigerated?

Question 1. It is a matter of taste. Over time there is a likelihood that the fat will start breaking down but that in itself is not harmful. The issue is whether the taste is affected. My Granny had a 'dripping pan' that used to hold fat that was returned time and time again to the weekend roast, with no ill-effect. Animal fats are generally too saturated to have oxidative rancidity and hydrolytic rancidity (the splitting of the fatty acids from the glycerol backbone of the fat) often cannot be tasted. A text book I read once famously said that a fat was rancid if it tasted rancid and that all other tests were, at best, just corroborating evidence.

The splitting of the triglyceride happens during digestion so it is no a health hazard as such.

So, in short: as long as the fat still tastes ok, it is fine.

Question 2. The fat layer is supposed to keep the meat protected. Despite what advertisers of disinfectants and such like would have you believe, bacteria do not spontaneously appear for no good reason. This is a habit solely retained for the start of a new Universe. If your duck is cooked, it will be sterile and the thick layer of fat will keep it sterile.

Has done so safely for many many years.

Green is more problematic but not necessarily harmful. The pigments in blood - haemoglobin and myoglobin, will oxidise and go funny colours, mostly green, grey and brown, with exposure to the air. Unsightly but not harmful. The surface of the chicken paté I make discolours quite quickly but is not harmful.

More important is to make sure that the exposed bones and such like are not handled as they do not have the layer of protective fat and will possibly give bacteria a toe-hold.
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Sunday, August 21, 2011

Stamps. And the perils of licking them.

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Stamp commemorating all that was left standing after the US 'liberated' Iraq?

Xink asks: Is it possible to die from licking stamps? As in the Seinfeld episode when George Costanza's fiance dies after licking cheap stamps for a wedding invitation mail out.

Good grief - we get further and further away from food chemistry!

Partly my own fault: My profile has a question on it: "What's the best time you've ever had licking stamps?" My response was "Ah, Stamps! Such a lovely girl. So many memories; how can I choose?" So I guess I have no-one to blame but myself.

The short answer is that I do not know of anyone dying from licking stamps but the mucilage that was put on stamps to act as the adhesive is a protein based material and, as allergenic reactions are generally a response to proteins, it is not impossible that someone may have a reaction.

◊◊◊

As for the Stamps of my profile. Yes, if her boyfriend found out, that could kill you.

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Thursday, August 4, 2011

The Hormonal Cow

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Celia asked: Lee, do you have any thoughts about growth hormones in Australian beef and what they're doing to us?

Well, yes, I have thoughts. Mixed thoughts.

I don't have too many facts, though, as it is a bit outside my experience.

Thoughts, in no particular order:

1. I have a general preference for no additives in food (don't you dare call them 'chemicals' unless you can name one thing on this planet (and beyond) that is not composed of chemicals) however I accept that sometimes additives to food are unavoidable.

2. The Safemeat site suggests that hormones are not harmful but that, while they increase meat yields, they decrease meat tenderness. This site is a joint venture between the meat industry and the Government.

3. Talking to another laboratory that tests HGP (Hormone Growth Promoters), they can only reliably find them in the area surrounding the injection point in the cow's ear. In other parts of the body they are too low to quantify.

4. Like it or not, we must increase our food production to meet the population growth; farmland is decreasing, so per-acre yields must increase. But we eat too much meat per meal, as a rule.

5. There is little evidence available to show that the nature-identical hormones are harmful. I am probably more comfortable with them than I am with the fully synthetic ones.

6. I would favour mandatory labelling.

So, in summary, I don't think they are harmful but would prefer they not be used.

But I am no expert.
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Wednesday, July 20, 2011

Steak Tartare

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Celia, of Fig Jam & Lime Cordial, asked "Does the traditional food rule apply to dishes like steak tartare?"

Yes, is the short answer.

Steak Tartare is a traditional food.

Despite the rantings of Professor A. C. Grayling, philosopher and vegetarian irrationalist, meat is not full of bacteria. (See here) Once you cut it, though, bacteria is introduced and the life of the meat starts being reduced.

A number of things need to be remembered:

  1. The amount of bacteria that you introduce in chopping the meat is quite small. Especially if you take care to use clean knife.
  2. Bacteria, at room temperature, will double in numbers every 20min, so what starts out as a low level can rise very quickly.
  3. Most spoilage bacteria is just that, spoilage bacteria. Pathogens, such as E-coli or Salmonella, are less prevalent and less likely to be introduced in the chopping of the meat.
  4. The concept of an 'infectious dose'. Everyday we are ingesting low levels of bacteria, including pathogens, with no ill effect. There is a certain level that is necessary to induce illness.

The long and short of it is that Steak Tartare must be made fresh and eaten fresh.

That is the traditional way to do it.

And it is quite safe.
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