Posted: February 10th, 2012 - 2:53pm
Source: M Live

KALAMAZOO -- If you're a grower for Kalamazoo's year-long farmers' market, it's not enough to get stuff to grow. Gardeners and commercial growers alike need to be careful with their practices to keep fruits and vegetables safe to eat, said a Michigan State University scientist.
And market shoppers?
"They need to ask lots of questions," said Phil Tocco, Michigan State University Extension educator.
Did you wash your hands before you picked that?
Do you use manure fertilizer? When did you apply it to the field?
What's the source of your irrigation water? How is it applied?
Those are questions consumers should routinely ask when they buy fruits and vegetables, whether from a market or roadside stand, especially if they are buying foods they plan to eat raw, or things such as lettuce, that grows very close to the ground, Tocco said.
Many food-borne illnesses can be transmitted to fresh produce in the field via improperly applied water, or water from an unclean source, Tocco said.
Others, such as norovirus, notorious for causing severe vomiting and diarrhea, can be shed from sick people for two weeks after their symptoms disappear, jumping from their hands to fruits and vegetables where the virus stubbornly clings and is nearly impossible to wash off, Tocco said.
Here are Tocco's tips for shoppers
In produce sections or at farm markets, watch people as they hand out samples, he suggested, and let that be your guide. If they say they'd never thought about washing their hands before entering the field to pick, move on, Tocco suggests.
"I've seen people giving out samples at Bank Street Market" without wearing gloves, slicing fruit with a knife and then lying it on a counter and picking it up again without washing it, Tocco said. "That's really, really bad," he said.
If a person is wearing gloves, and using a single-use paper towel to wipe the knife between uses, that's someone you want to buy from, he said.
Commercial growers and home gardeners need to know and follow the steps they can take to keep the fruits and vegetables they raise safe to eat, too, Tocco said.
Watering
According to a recent article authored by Tocco and published in MSU Extension News, growers should consider several things before they water, for instance:
How water is applied
All else being equal, here's how the application risks rank:
Highest risk: Overhead irrigation poses the most risk of contaminating a crop.
Food-borne illness pathogens that may be carried in the water can splash on fruits and vegetables with overhead watering, he said.
Medium risk: Surface irrigation, such as exposed drip tape on top of the soil, poses less risk than overhead spray.
Least risk: Underground irrigation, such as buried drip tape or drip tape under plastic, poses almost no risk of contamination because the water it doesn't come into contact with the fruit or vegetable.
When water is applied
High risk: If the crop is within two weeks of harvest, or there are fruit present on the plant, the risk of contamination is increased significantly.
Low risk: If the plant is in a vegetative state or more than a month from harvest, then there is a relatively low risk of contaminating the crop.
Where the irrigation water comes from
High risk: Rivers and streams pose the greatest risk of contamination. Because the water is constantly moving, there's no way to test it for purity to assess its risk, Tocco said. "Also, because a river is water running off soils over a large swath of land, there are many sources of contamination -- manure, bird droppings, etc.
Medium risk: Ponds are an intermediate risk. Although water quality can be tested, Tocco said, " the bummer there is that a lot of birds and water fowl land on or around them, defecating in the water," he said. " Farmers have to deter birds from nesting in ponds" they plan to use for irrigation, he said.
Low risk: Municipal and well water sources.
Tocco said water collected in rain barrels from running of the roof has sources of organic matter and dark underground cisterns " are the perfect breeding ground for bacteria," he said. That water may be fine for dumping around trees or to water vegetables that will be cooked before they are eaten, he said, but probably not for watering lettuce.
Other tips
Manure used as fertilizer should be applied more than 120 days before harvest and at least two weeks out from planting. Lettuce is almost too risky to fertilize with manure, Tocco said.
When in doubt, one old fashioned method of disease control still works well, Tocco said.
"Grandma and great-grandma cooked the snot out of stuff," a practice that kills germs as well today as it did then.