Garden vegetables are free of human pathogens unless they become
contaminated. The task for gardeners is pretty simple: don’t mess
up a good thing. The key to food safety is preventing
contamination.

Until recently, the term “safe” vegetables meant mainly that they
were free of harmful chemicals or contained them in such low
concentrations that they didn’t threaten anyone’s health.

There was, and still is, a lot of emphasis on using only
pest-control chemicals approved for vegetable crops, applying
them at the prescribed concentrations and frequencies, and
allowing for ample waiting periods before harvesting.

These safeguards are still essential in helping keep garden
vegetables safe.

Prevent, Reduce Contamination

In the late 1980s and ’90s, a number of produce-related illness
outbreaks prompted the 1997 start of a federal program to
help keep fresh produce safe.

This new initiative stressed preventing and reducing the
contamination of fresh produce with human pathogens (living
things that make people sick).

The concept of safe food was broadened to include being free of
disease-causing microbes such as Salmonella, E. coli
0157:H7, Shigella, etc., and parasites such as
Cryptosporidium and Cyclospora.

Producing “safe” fresh vegetables in the garden is fairly easy,
because vegetables aren’t a primary source of human pathogens.
Fortunately, the bacteria, fungi and viruses that sometimes make
plants sick don’t make people sick.

How Veggies Get Contaminated

How do garden vegetables get contaminated with the “bugs” that
make people sick?

The most likely source in the garden is animal manure. But animal
manures are good for the garden. They contain essential nutrients
that help plants grow. And their organic matter improves
soils.

The good news is that gardeners can reap manures’ many benefits
and still grow vegetables free of human pathogens.

Use composted manures.

The heat generated during the composting process destroys human
pathogens. Besides making the food safer, properly composted
manures are much more helpful to the garden than raw manures.

Must Be Properly Composted

Keep in mind, though, that improperly composted manures are
likely to contain as many pathogens as raw manure. Don’t use
them.

If you aren’t sure the manures you want to use have been properly
composted:

• Apply them only after the vegetables have been
  harvested.
• Fully incorporate them into the soil.
• And wait at least three months before planting food crops in
  the garden.
• Don’t use them on perennial vegetables and root crops.

Watch Out for Animals, Too

Speaking of animal manure, living animals often visit the garden.
Pets, deer, racoons, rodents and birds can carry human pathogens
and may contaminate the garden with fecal matter.

Be aware of this potential problem. Keep on the lookout for the
telltale signs that they’ve been active in your garden. If
animals or birds do visit your garden, take measures to keep them
out.

By applying chemicals properly, using composted manures and
keeping animals out of your garden, you can help make sure your
picture-perfect vegetables are not only fresh and nutritious, but
also safe to eat.