The alternative to the killing zone is the velvet rope approach, whereby you let certain microbes into the party with the understanding that they won’t go bustin’ up the place. This is the world of fermented pickles which includes things like gherkins, sauerkraut and kimchi.
The principle behind it is rather elegant. It is, simply, that all fruits and vegetables contain within them certain types of beneficial bacteria. These bacteria perform several functions, one of which is to control the reproduction and spread of other harmful bacteria, molds and fungi. They do this by producing certain kinds of anti-microbial compounds like acid and alcohol. These types of microbes, as it happens, are not only safe for us to eat, they’re delicious. Thus, all we need to do is create an environment where they can thrive and our vegetables and/or fruits will be preserved (for us).
If you read my posts on bread starters all those weeks ago, you see that there’s very similar logic at work: let the microbes duke it out until there’s only one bug left standing. In the case of pickles that will, depending on how much salt is in the pickle brine, either be Lactobacillus plantarum or Leuconostoc mesenteroides. And yes, lactobacilli (lactic acid bacteria) are the same type of bacteria that make sourdough bread taste so good.
It’s pretty neat science, though it’s science I’ve never been very good at. Fermentation pickling requires fairly precise temperature control, usually slight variations of room temperature which I have a difficult time maintaining. I remember the last time I tried to make kosher dills. Everything seemed to be going fine in the jar, nice clear brine and plump, inviting pickles. When I reached in to pull one out I discovered that they were nothing but empty bags of cucumber skin. Some microbial critter (possibly even one of the “good” ones) had moved in and completely consumed the flesh.
Happily, there’s an entire universe of so-called “refrigerator pickles” out there to explore, some of which (notably Mexican pickled red onions) can be ready in as few as a couple of hours. True, they don’t keep as long as the fermented kind, but they’re every bit as flavorful, even more crispy, and in most cases last for weeks.