Southeastern U.S. Vegetable Crop Handbook - 2023 - 33

Chlorine. Injury from chlorine is usually of an acute type, and it
is similar in pattern to sulfur dioxide injury. Foliar necrosis and
bleaching are common. Necrosis is marginal in some species,
but scattered in others either between or along veins. Lettuce
plants exhibit necrotic injury on the margins of outer leaves,
which often extends into solid areas toward the center and base
of the leaf. Inner leaves remain un marked. Crops sensitive to
chlorine are: Chinese cabbage, lettuce, Swiss chard, beet, escarole,
mustard, dill, pepper, potato, spinach, tomato, canta loupe,
corn, onion, and radish.
Ammonia. Field injury from NH3
has been primari ly due to accidental
spillage or use of ammoniated fertilizers under plastic
mulch on light sandy soils. Slight amounts of the gas produce
color changes in the pigments of vegetable skin. The dry outer
scales of red onions may become greenish or black, whereas
scales of yellow or brown onions may turn dark brown. In addition,
chicken litter may be high in ammonia (NH3
nium (NH4
) and ammo),
and if sufficient time is not allowed between litter
application and planting, substantial damage from ammonia toxicity
may occur to seeds or seedlings.
PRODUCE SAFETY
While there are many regulations and buyer requirements that
surround produce production, the ultimate goal is for fruits and
vegetables to be as safe as possible for all families and communities.
This section provides a simple overview of produce safety
and provides some resources for your farm. It is estimated that
over 48 million individuals are sickened by foodborne illnesses
yearly in the US, and nearly half (46%) are caused by outbreaks
linked to fresh produce. Fruits and vegetables can become contaminated
at any point in the production chain. Once contamination
occurs, it cannot be removed from the produce and, since
many crops are eaten without cooking, prevention is the most
important step in reducing outbreaks. Microorganisms that can
cause foodborne illnesses are commonly found in human and
animal feces, including Salmonella, pathogenic E. coli (e.g.,
O157:H7), and Campylobacter spp. Some viruses, such as norovirus
and hepatitis A, can also survive for longer periods and can
contaminate fresh produce. Human parasites are not commonly
associated with produce contamination in the US; however, Cyclospora
cayetanensis has become an emerging concern in the
past few years, especially in irrigation water sources.
Foodborne pathogens can cause mild to severe illnesses depending
on several factors, including the number of pathogens
in the food, health of individuals, the strain of the microorganism
that is causing illness, and the type and amount of contaminated
food consumed. Symptoms might take hours to days to
appear. For example, people with Salmonella infections might
have no symptoms; while others develop diarrhea, fever, and
abdominal cramps within 8 to 72 hours. Most healthy people
recover within a few days without treatment and do not need to
be hospitalized. On the other hand, Listeria monocytogenes can
be serious to pregnant women, people older than 65, and people
with weakened immune systems. Listeriosis symptoms can
start from 1 to 4 weeks after consuming contaminated food.
2023 Vegetable Crop Handbook for Southeastern United States
WHAT ARE GOOD AGRICULTURAL
PRACTICES (GAPS)?
The term Good Agricultural Practices (GAPs) refers to basic
practices that minimize food safety risks. The purpose of
GAPs is to provide guidance for the safe production, packing,
handling, and holding of fruits and vegetables resulting from
a well-developed farm food safety plan. Worker hygiene and
health, manure use, and water quality throughout the production
and harvesting processes are areas that GAPs cover. Growers,
packers, and shippers are urged to take a proactive role in minimizing
food safety risks associated with fresh produce. Furthermore,
operators should encourage the adoption of safe practices
by their partners along the farm-to-table food chain. This
includes distributors, exporters, importers, retailers, transporters,
food service operators, and consumers. Being familiar with
potential biological, chemical, and physical hazards that exist on
the farm is the first step toward minimizing risk. This helps to
protect the consumer, as well as the growers' families, communities,
and livelihoods. Some of the areas of the farm that could be
potential sources of contamination and should be considered are:
* The growing site: Take into consideration the surrounding
area, topography, soil amendments, and irrigation water
source. Think about the effect of surrounding land use on
contamination of produce and how GAPs will be implemented
to reduce risk long before planting. Recent research
has shown the potential for nearby animal production areas
to contaminate produce through irrigation water and wind
spread. Vegetative buffers, berms, diversion ditches, and
woody areas may help reduce this risk. Furthermore, planning
for the use of manure and compost and using it safely
is key to producing the safest possible product.
* Water use: If water touches the harvestable portion of the
crop or is used on surfaces the produce touches after harvest,
then water quality becomes a key concern. In these
situations, water should be tested to ensure that it meets
current microbial quality guidelines. The U.S. Food and
Drug Administration (FDA) and the Produce Safety Alliance
(PSA) are reliable sources for this information.
* Domesticated and wild animal intrusion: Both domesticated
and wild animals can carry and shed human
pathogens. Sometimes this is because they have carried
pathogens from a nearby animal production area or human
contamination source. It is important to minimize contamination
from animals in the production and packing areas,
including farm pets. Most growers are already doing a lot
to prevent animals from damaging their crops.
* Worker hygiene and sanitation: Provide workers with
appropriate training to help them understand the importance
of hygiene in handling produce. Providing convenient,
clean, and well-stocked restrooms and handwashing
facilities will enable workers to properly wash hands after
eating, smoking, handling non-produce items, using the restroom
and other times when hands may have become contaminated.
Sick workers must be restricted from handling
produce so that they do not pass along pathogens.
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Southeastern U.S. Vegetable Crop Handbook - 2023

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