Very occasional thoughts concentrating on the useful.

Tuesday, April 25, 2006

My strawberries never mold

They actually don't! I got a foodsaver vacuum canister to store my strawberries in, and the vacuum suffocates the mold.

I tested the vacuum, and found that inside the canister the pressure is 1/5 of an atmosphere. I wouldn't want a perfect vacuum, because deadly botulism bacteria grows only in the absence of oxygen.

I've never bothered to get any of the vacuum sealing bags. I also got the attachment for vacuum packing in mason jars. Unlike the canisters, the mason jars can be frozen (even with liquids if you get the freezer-safe jars). Unfortunately, the quality of the vacuum inside a mason jar is variable.

You can see how good the seal is by placing bubblewrap inside before sucking out the air.

I've also had good luck vacuum-packing
  • ripe avocados: the inside never goes from green to brown. They keep for about three times as long, but they'll eventually go mushy.
  • guacamole: it never turns brown.
  • frozen vegetable soup
  • frozen vacuum-packed omelets. They come out still smelling good.
  • cabbage

I haven't tried blueberries yet.

Update 5-16-2006: My tomato juice keeps much better when vacuum-packed.

Update 8-1-2006: Romaine lettuce is still crisp and tastes fresh after a week. (Of course, our tongues evolved without vacuums around, so perhaps it degrades in ways you can't taste.)

Sunday, April 16, 2006

The "Zero Trans-Fat" scam: Will someone please teach the FDA to use fractions?

My housemate's "Olivo Spread", which claims to be a healthy butter substitute, claims to have "zero trans fat". But the labeling lists trans-fat (more properly known as "hydrogenated" or "partially-hydrogenated oils") in the ingredients! The same goes for Ritz crackers.

What gives?

I found the answer in the article:

"Waging war on `metabolic poison',"
by Lisa Ryckman, "The Journal Gazette", April 9 2006.

The key points are:
  1. Prof. Walter-Willett and his colleagues from the Harvard nutrition department estimate that
    trans-fat is killing 100,000 Americans per year! Obviously, it should be completely eliminated from our diets.

  2. Fortunately, new FDA regulations require food labels to list trans-fat content, but unfortunately

  3. The trans-fat content is rounded to the nearest gram, no matter how small the serving size is! Hence for items with very small serving sizes (such as butter substitutes or crackers) the "zero trans fat" may actually be a significant proportion of the product!

  4. A product contains no trans fat only if the list of ingredients does not contain "hydrogenated oils" or "partially-hydrogenated" oils.
In the case of Olivo or Ritz crackers (serving sizes 14 and 15 grams, respectively), it would be consistent with the labeling to have a trans-fat content of about 1/30 by mass.

For more information, see Willett's book or