A load of old rhubarb

.

I made mention on my home blog that my rhubarb was green and that I was adding elderberries to it to make it look more 'normal'.  I have seen recipes that added strawberries to give colour.  A few people asked if green rhubarb was safe.

Yes, it is.

The green stemmed rhubarb is a fast growing, thick stemmed hybrid.  Quite safe.

The poisonous element in rhubarb is a chemical called Oxalic Acid and it is found at high levels (0.5%) in the leaves, regardless of the stem colour.

Oxalic Acid is also found in many other plants but not at the levels found in rhubarb leaves.  Excessive Oxalic Acid consumption results in kidney stones (Calcium Oxalate).  A lethal dose of rhubarb leaves is about 5kg.
...

Stamps. And the perils of licking them.

.

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.

...

Steak Tartare

.

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.
...

Of meat and fridges...

.

The Intolerant Chef asks: "How long can raw meat be kept in the fridge before being harmful? I remember my mother washing slightly bluish looking chops in vinegar and water to remove the stickiness and smell before cooking them. They were then fed to my father, never us children or her."

I assume your father was well insured.

Generally, fresh meat can only be kept for a few days at refrigeration temperatures. It is hard to butcher meat without getting bacteria on its cut surface and bacteria love a warm, protein rich surface.

Note: these are bacteria introduced during the butchering process and not endemic to the meat as such. When the meat is 'hung' after slaughter, the surface of the carcass is dry and intact and no bacterial degradation takes place. Once the meat is sliced or minced, bacteria is introduced and all bets are off.

Chilling meat slows bacterial growth but doesn't stop it. Freezing it stops the growth. As does drying.

Bacterial growth results in the breakdown of proteins which in turn produce the unpleasant smells that we associate with 'off' meat. Rubbing the meat with vinegar may reduce the bacterial load and reduce the smell. Traditionally curry was also used to hide off meat.

It would be the thorough cooking afterwards that killed the bacteria and made it safe for your father to eat.

Probably with lots of sauce.
...

Revisiting Alfalfa Sprouts

.
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.
...

Curry Powder

.

Sara asked about curry powder.

There is absolutely nothing wrong with curry powder. It has been safely used for many centuries, following time honoured and well proven practices.

But what if those practices are not followed?

First, let's look at what curry powder is. It is the ground mixture of spices, seeds of a variety of plants. Seeds that have been exposed to the environment. There is nothing abnormal in that but, because of their origin, the seeds that go into curry powder will bring with them a variety of organisms from the environment. Notably Salmonella.

Now, how is curry traditionally prepared? You heat oil in a pan and cook the powder in this oil. Ostensibly to 'bring out the flavour' but, by a happy coincidence, it also sterilises the powder. You then add meat, vegetables, whatever and continue with making your curry.

What happens if you deviate from this long proven, survival enhancing, cooking practice? What if you are a new age cook and make a curried pasta salad where you just mix the warm (!) pasta, mayonnaise, vegetables, cream and curry powder and stir? Nothing much if you eat it straight away. But bacteria will double roughly every 20min at room temperature; what if you make your salad early and leave it for a few hours before eating? Not a good idea - the salad is warm, moist and protein rich - happy times for the bacteria.

Because of the risk, spices are one of the few things that are permitted to be irradiated to sterilise them. But this does not teach people safe handling practices for a potentially dangerous food. People will just be ignorant of the dangers and at risk from spices that are not irradiated.
...

Onions as bacteria magnets.

.
Pauline asked: there is an email circulating claiming that cut onions are "magnets for bacteria" and should never be stored for later use (even in the fridge for a few days) as they will cause food poisoning. True?

Snopes (here) rates it as "undetermined".

I am willing to go out on a limb and say "false".

Reason 1: Nothing is a bacteria magnet. Firstly, bacteria have minimal mobility. They usually travel in water droplets, if at all. Sneezes, for example. Moulds can release spores which get blown around but bacteria usually grows in moist environments and are slimy, making getting airborne difficult. Secondly, if there was such a thing as a 'bacteria magnet' it would be enormously useful in the medical field for drawing bacteria away from the ill and infirmed. Not such use has been made of onions.

Contact with unclean hands can introduce bacteria to new surfaces but they need a surface that will support growth, otherwise they will just stay there without multiplying or die.

Reason 2: Bacteria like moist, neutral environments. Not many acidic things grow bacteria. That's why vinegar is used for preserving. The surface of a cut onion is acidic due to the production of sulphuric acid (this is what makes your eyes water). There are some moulds that will tolerate acidic conditions and grow on onions but they are not high risk, they are visible, and any normal person would cut them off or ditch the onion.

Reason 3: High risk foods are usually high in protein and available moisture. Onions are low protein, verging on nil, and what moisture they have is contained in their cellular structure. The surface, as well as being acidic, dries soon after cutting and will not support bacterial growth.

Reason 4: If onions are attracting bacteria, where are they coming from? Somewhere else in your fridge? Perhaps it is time to clean the fridge.

Reason 5: In the 20 odd years I worked in a food laboratory, onions were never mentioned as even a suspect in a food poisoning case.

-------
Footnote: we did have some onions brought to the laboratory as a food poisoning complaint once. A guy had eaten them and ended up in hospital. Only problem was, they weren't onions.

They were daffodil bulbs.
...

The case for tougher rats.

.

Chairman Bill, in a comment to the last post, deemed hydrogenated fats to be carcinogens.

While I took some issue with the broadness of the statement, I do agree in a broader sense.

At a different level, I believe EVERYTHING causes cancer. You just need more of some things than others.

In a broad sense cancers occur when the body's systems are overwhelmed by a particular compound or radiation. Even shift work is implicated in cancers nowadays. It is a case of the body getting swamped in someway and losing the plot when it comes to cell growth.

Tests in the labs have shown that if you swamp a lab rat's diet with a chemicals it will develop cancers but, in order to speed up the process the labs feed the rats enormous amount of the compound being tested. If you want to see what they went through, make a mix of a food of your choice and include 5% saccharin. Inedible. Now do it all meals for an extended time. Unbearable. No wonder the poor rat developed cancer. But how does swamping a rat's genetic processes translate into the long term effect of low levels of a saccharin on humans?

Bill talked about trans fats in margarines but they are naturally occurring in most fats.

In low levels.

It is generally accepted that smoking causes cancer; this is due to the compounds in the tars. Theoretically these compounds are first cousins of the charring of any plant matter. Smoking marijuana is just as dangerous as tobacco in this sense - different psychoactive substances, same tar.

But burnt plant matter is common in our diet - browned meat, roasted coffee, toast, cakes, biscuits, fries/chips. All theoretically foreign and carcinogens.

I argue that all chemicals, taken in excess for extended time will swamp the system.

I also argue that the system is designed to cope with a multitude of chemicals that are naturally in our food. The analogy would be sand. If I drop a stream of sand on your shoulder, it will bounce off and not be a problem. If I drop a ton of sand on you all at once, it is a big problem.

It is all a matter of recognising and managing risk.
...

The most dangerous food in the world!

This is a repost from A Curate's Egg, but it is topical (re The Fat Duck post) and really belongs here .

In my previous incarnation as a food chemist I was often asked ''What food shouldn't we eat?"
I'm not sure what people expected me to say.

Butter, maybe.

In the incarnation prior to that one, I worked at the Coroner's Court doing post-mortem drug analyses. No one ever asked me what drugs they shouldn't take.

However, there I am, Food Chemist, at a dinner party or a BBQ and after the obligatory "What do you do for a living?" question I get the "Oh, really? What food shouldn't we eat?" question. Always tricky if you don't know what is on the menu. But few people are ready for my reply.

Alfalfa sprouts.

Yes, those clean, green, biodynamically pumped shoots are one of the most treacherous foods on the menu.

"Surely not! You're joking, right?"

Wrong.

Think about it. Seeds of any sort are open to the environment. They will have bacteria on them. So what do you do with them? You soak them in water and leave them somewhere warm for three days. Water, warmth, and the seed, a good souce of protein. Bacteria heaven.

"But sprouts have been eaten for centuries." they protest.

"Cooked" I respond. Eating sprouts raw is a recent 'healthy' practice.

Cooking sprouts will kill any bacteria.

That doesn't mean that raw sprouts are bad, just that they are high risk. There is no safety net.
You can reduce the risks by using boiled or chlorinated water and changing the water frequently.

"Now, would you like my thoughts on curry powder? Or margarine?"

"Ah ... that's very kind of you but I can see an actuary over there that I have been dying to talk to ... "