Sunday, May 3, 2009

Can You Believe It? Chemicals in Canned Foods

As fear is de rigeur these days--fear of terrorism, fear of disease, etc.--and swine flu is the illness du jour, James decided that we should stock up on a lot of canned food and bottled water in order to be prepared for any upcoming pandemics that may bring civilization to a crashing halt.

I don't buy a lot of canned food, and this shopping trip reminded me why. Many canned foods that are not desserts have sugar in them, in flagrant disregard of common sense and the obesity epidemic. It is also disheartening to see that high-fructose corn syrup has crept north across the border and is insinuating itself into more and more prepared foods, though studies show it destabilizes your blood sugar levels and encourages weight gain even more than plain table sugar does.

But it was the raft of mysterious chemicals in the cans that really made an impression on me. Actually, the worst offender didn't come in a can but in a jar. We happened to wander into the multicultural section of the supermarket. I saw they had gefilte fish, which made me come over all nostalgic. Gefilte fish was no big deal when I lived in Montreal, but here, Jewish things, edible or otherwise, are harder to come by. So I got a jar of Manischewitz Gefilte Fish. I picked that brand because it was the only one without sugar, but it turned out to be an unfortunate choice. There are worse things than refined sugar. I know that now.

It should have been good. How can you go wrong with carp, mullet, whitefish and pike? All tasty fish, or at least hairdos of the 70's. But it had an unpleasant, metallic taste, like a thallium patty. What could have imparted such a disgusting flavour? It wasn't the fish. It couldn't have been the onion or the egg whites. It probably wasn't the monosodium glutamate; sometimes I get a reaction to MSG, but I've never noticed that it had a taste. But it could have been the sodium hexametaphosphate. Or perhaps the sodium tripolyphosphate.

If my hair falls out, I'll let you know.

Manischewitz wasn't the only offender. Most of the canned foods we bought had some kind of laboratory oddity in them. I thought it would be interesting to round up all the chemicals in all the canned and bottled foods we bought and find out more about them. So here they are, in alphabetical order.

Chemicals in Cans

Autolyzed Yeast Extract
In No Name Chicken Stew. A flavour enhancer similar to MSG, which is also in No Name Chicken Stew. Why do they need the same thing twice? They must not have a lot of confidence in their stew. According to Wise Geek, autolyzed yeast is created by adding salt to yeast, which causes the yeast to digest itself[1]. Some sort of undisclosed further processing creates the final product. Autolyzed yeast extract is chemically similar to MSG and may therefore produce similar symptoms.
Calcium Chloride
In canned tomatoes, all brands I've checked. Used to keep canned vegetables firm. Disconcertingly, it's the same stuff they put on the road to melt ice in winter. Can be an irritant, though presumably in larger quantities than one finds in canned food. Considered safe.[2]
Citric Acid
In Aylmer's Canned Tomatoes. Naturally occurring in fruits and vegetables, especially citrus fruits. Added to foods as a flavouring and preservative[3]. My can of tomatoes explains that citric acid is an acidulant. Acidulants, also called acidity regulators, change or maintain the PH balance of foods[4]. This is a bit confusing. Tomatoes are acidic on their own. Why do they need an acid added to them? Could they lose acidity otherwise? Anyway, no safety concerns there.
Disodium EDTA
In Unico Bean Medley. EDTA is short for ethylene diamine tetraacetic acid. Now there's a mouthful. One study shows that sufficient quantities of the stuff cause negative effects in rats. All rats dosed with the rat equivalent of 500 mg died within nine days[5]. And 500 mg is not all that much. Vitamin C comes in 500 mg pills. The study concludes that "because of its effect on calcium, the use of disodium EDTA as a food additive is not recommended" [6]. Oh dear. Perhaps the bean medleys will have to go back to the store. The study adds that calcium disodium EDTA is safer than plain old disodium EDTA. That's good, because I just noticed it's in my mayonnaise.

The Health Canada Food Additive Dictionary explains that disodium EDTA is a sequestering agent[7]. Sequestering agents "combine with metallic elements in food, thereby preventing their taking part in reactions leading to colour or flavour deterioration"[8]. So though it does bad things to blood calcium levels, at least if you're a rat, disodium EDTA is permitted in our food so that our canned beans will stay pretty. Uh, yeah. That's worth it. Not.

Granted, this is quite an old study. But I can't find anything more up to date. There's surprisingly little information out there about disodium EDTA as a food additive.
Monosodium Glutamate (MSG)
In No Name Chicken Stew, all Campbell's Soups, and Manischewitz Gefilte Fish. A sodium salt of glutamic acid. Glutamic acid occurs naturally in seaweed and was traditionally used in Asian cooking. MSG is added to foods as a flavour enhancer[9]. Although it is considered safe, in sufficient quantities it can cause a reaction known as MSG symptom complex or--more colourfully--Chinese restaurant syndrome[10]. I have experienced that myself. I get a weird, itchy feeling in my throat. Other people get headaches. Asthmatics may experience temporary worsening of their asthmatic symptoms[11]. I have only had problems in Chinese restaurants; presumably the amount found in some restaurant dishes is larger than in canned food. I suspect that the original seaweed extract caused fewer problems than the MSG cooked up in labs, but progress marches on.
Sodium Hexametaphosphate
In Manischewitz Gefilte Fish. This is another sequestering agent (see Disodium EDTA). Its Wikipedia entry claims it can cause chest pain, and in sufficient amounts, pancreatic cancer, but the citations are missing[12]. According to Cosmetic Database, there are a number of concerns regarding this chemical: it is persistent and "bioaccumulative," which means that it builds up in your body tissues[13]. As well, studies in animals show that it affects the brain and nervous system in high doses [14].
Sodium Tripolyphosphate
In Manischewitz Gefilte Fish. Used as a preservative in meats and fish. It is also added to soaps and detergents to improve their cleansing ability![15] Polyphosphates are irritating to the skin and may induce metabolic acidosis[16]. Which, by the way, can be fatal.
In No Name Chicken Stew. The specific type of sulfite was not mentioned; the ingredient listing simply said "sulfites (in potatoes)." Sulfites are used as a preservative. In some cases, they just make the food look prettier. If you've ever seen dried apricots in a health food store, you've probably noticed that they are dark brown, in contrast to supermarket apricots, which remain bright orange. That's because the health-food apricots have no sulfites in them. They still taste good though.

Sulfites occur naturally in wine and some foods. Yet they are a health concern. They can cause headaches, skin irritation and breathing difficulty[17]. Asthmatics are at greater risk of having a reaction to sulfites, a reaction that can sometimes be fatal[18].

Bon app├ętit!

Notable Exceptions

Having gone on at length about the additives in canned food, some benign and some scary, I feel it's only to fair to mention that some of the canned food we bought had no chemicals in it at all. If you prefer your food unadulterated, here are some products to watch for.

  1. I have to hand it to Blue Menu. They really do make healthy products without unnecessary additives. Their soups are free of MSG and their canned beans contain nothing but beans, water and salt, in constrast to Unico's beans with their rat-sickening disodium EDTA. Furthermore, Blue Menu's canned corn kernels contain no added sugar. Yet they still taste sweet, probably because they come from good quality corn.
  2. A can of Del Monte's Pineapple Chunks contains nothing but pineapple chunks and pineapple juice.
  3. President's Choice Just Apples "Appletreet" consists of little individual plastic cups of applesauce. It's not canned food per se, but it is similar to canned food, being sealed in airtight containers, and does indeed contain just apples. Too bad about the silly name though.
  4. NATUR Peanut Butter comes in a glass jar and consists of nothing but ground peanuts. Unlike most peanut butters, NATUR contains no hydrogenated oil.


  1. ^
  2. ^
  3. ^
  4. ^
  5. ^
  6. ^ Ibid.
  7. ^
  8. ^
  9. ^
  10. ^
  11. ^ Ibid.
  12. ^
  13. ^
  14. ^ Ibid.
  15. ^
  16. ^
  17. ^
  18. ^ Ibid.


Anonymous said...


Vivian said...

This is why I cook my own food, mostly.

Anonymous said...


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