Harvest And Postharvest Techniques To Prevent Bacterial Soft Rot

Bacterial Soft Rot

Producing a healthy crop obviously is of the utmost importance to vegetable growers, and among the key factors necessary to get quality produce to market is the care taken from harvest to packing.

One problem experienced by growers of tomatoes, potatoes, and others is the postharvest attack of the bacterium Erwinia sp., known otherwise as bacterial soft rot. Soft rot can become a serious issue, particularly when care is not taken to prevent bruising, etc. during harvest and proper postharvest food safety practices are not adhered to in packing areas.
In addition to proper postharvest handling, having the adequate levels of nutrients in the plants while they are growing in the field — especially calcium — is important for reducing the effects of this bacteria. It is reported that in warm, humid climates, bacteria can affect the inside of stems and the epidermis.

One of the first crops attacked by bacterial soft rot is tomatoes. Four species of bacteria are known to cause infection. In addition to tomatoes, the bacterium has been reported on other crops as well, such as potatoes, peppers, carrot, lettuce, cabbage, and onion.

Soft Rot Symptoms

Many symptoms will help growers identify soft rot in their fields. Specifically, infected fruit show soft, odiferous lesions. The spots are small, sunken areas that are watery in appearance. These injuries range from a light to slightly darker color and are related to the natural openings or wounds in the fruit. There may be a characteristic discharge coming from the wound that is made up of millions of bacteria.

Erwinia can affect roots and stems, causing darkening of the tissues. The bacteria in potatoes is called blackleg, and can cause plant death.

Survival Of The Pathogens

What makes soft rot critical to control is that bacteria can survive on vegetables in various parts of the plants and also has the ability to live in low populations in the soil and water.

It is important to note that this strain cannot penetrate the plant; it
can only enter through a previously sustained wound or natural opening in the tissues. During handling, if bruises and wounds occur, and if the water is not disinfected well, the pathogens can enter the fruit.

In potatoes, the main source of inoculum is from the seed tuber, machinery that has been in the field, and irrigation water. The bacteria is active when conditions are favorable for pathogen growth and development — excess moisture, poor aeration, damaged tissues, and a high presence of inoculum.

Leave a Reply

2 comments on “Harvest And Postharvest Techniques To Prevent Bacterial Soft Rot

  1. No company has a single “silver bullet” to eliminate plant and human health pathogens on fruits and vegetables; however, growers and packers armed with a “silver clip” can successfully control pathogens and produce a quality product. Years ago this process was call the Hurdle Approach. I am pleased to find in this article the mention of potential cross contamination from irrigation water and farming equipment. One of the first hurdles to be considered prior to planting is treating the soil to control soil pathogens. A second hurdle is to treat irrigation water. The third hurdle should be to clean and sanitize filed equipment and transportation vehicles to prevent cross contamination from field to field and field to packing house. Once produce enters the packing house there are a number of antimicrobial hurdles to consider. For example, hydro coolers, wash tanks, spray bars and fogging units can be antimicrobial hurdles. A final hurdle that grower and packers cannot control is the consumer washing the produce prior to use. Field to fork hurdles are necessary to assure high quality and safe vegetables. Russell

Featured Stories
Thomas Björkman, the director of the Eastern Broccoli Project, discusses details on the challenges of broccoli production in the East.
Vegetables
February 7, 2016
The Eastern Broccoli Project Moves Forward
As acreage increases in the East, mid-sized growers seek channels to distribute their product and continue the search for varieties. Read More
Apples On Display
Fruits
February 6, 2016
Best Research Is Industry Driven [Opinion]
Like many of you, I’m not crazy about a lot of government programs. It’s not that their genesis isn’t noble; God Read More
RosBREED will have an impact on nearly all the major U.S. rosaceous crop production areas.
Fruits
February 6, 2016
RosBREED: A National Effort To Improve The Fruit Industry
The project focuses on improving disease resistance and fruit quality through better genetics and breeding. Read More
Biofungicides supplement methyl bromide alternatives
Berries
February 5, 2016
Moving Beyond Methyl Bromide With Biofungicides
Editor’s note: University of California Farm Advisor Mark Bolda will present much more information on this topic at the Biocontrols Read More
Geotextiles being installed.

Photo: Jim Willwerth
Grapes
February 5, 2016
Geotextiles Can Help Prevent Winter Grapevine Damage
Although Northeast and Midwest grape growing regions have so far been spared from extreme cold this year, the winters of Read More
The canopy of the vines that received the under-canopy sprinkler irrigation just on hot nights during heatwaves appear to be healthier than the control vines and have a higher yield.
Photo: Michael McCarthy
Grapes
February 5, 2016
Researchers Test New Method To Mitigate Vine Heat Stress
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
Biocontrols USA 2016 logo
Crop Protection
February 5, 2016
Register Now For Biocontrols Conference 2016 Field And Greenhouse Tour
Space is limited, so register now to attend the first-ever Biocontrols USA 2016 Conference Field and Greenhouse Tour. Following the Read More
La Crescent produces a good quality white wine with apricot-like flavor. The off-dry, sweet white wine pairs well with appetizers, seafood and chicken. La Crescent has excellent winter hardiness with moderate disease resistance that requires a standard spray program.
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market For Cold-Hardy Grapes
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
two glass goblets of olive oil
Citrus
February 4, 2016
Can Olive Oil Grease Skids For Florida’s Slipping Citrus Trade?
Researchers, interested growers help launch new industry. Read More
Sunkist organic lemons being harvested at the Donlon Ranch in Ventura County, CA by Jane and Ned Donlon, 5th and 6th generation growers, respectively.
Citrus
February 3, 2016
Sunkist Expands Organic Portfolio
With the organic citrus sector growing three times as fast as conventional, the 123-year-old cooperative is keeping up with the times. Read More
The Latest
Vegetables
February 7, 2016
The Eastern Broccoli Project Moves Forwa…
As acreage increases in the East, mid-sized growers seek channels to distribute their product and continue the search for varieties. Read More
Fruits
February 6, 2016
Best Research Is Industry Driven [Opinio…
Like many of you, I’m not crazy about a lot of government programs. It’s not that their genesis isn’t noble; God Read More
Fruits
February 6, 2016
RosBREED: A National Effort To Improve T…
The project focuses on improving disease resistance and fruit quality through better genetics and breeding. Read More
Berries
February 5, 2016
Moving Beyond Methyl Bromide With Biofun…
Editor’s note: University of California Farm Advisor Mark Bolda will present much more information on this topic at the Biocontrols Read More
Grapes
February 5, 2016
Geotextiles Can Help Prevent Winter Grap…
Although Northeast and Midwest grape growing regions have so far been spared from extreme cold this year, the winters of Read More
Grapes
February 5, 2016
Researchers Test New Method To Mitigate …
The use of evaporative cooling in vineyards during hot weather isn’t a new concept, but researchers in Australia are testing Read More
Crop Protection
February 5, 2016
Register Now For Biocontrols Conference …
Space is limited, so register now to attend the first-ever Biocontrols USA 2016 Conference Field and Greenhouse Tour. Following the Read More
Grapes
February 4, 2016
Northern Grapes Project Fuels A Market F…
 There’s a burgeoning market for cold-weather grapes. The Northern Grapes Project, funded in 2011 by a USDA National Institute of Read More
Citrus
February 4, 2016
Can Olive Oil Grease Skids For Florida’s…
Researchers, interested growers help launch new industry. Read More
Citrus
February 3, 2016
Sunkist Expands Organic Portfolio
With the organic citrus sector growing three times as fast as conventional, the 123-year-old cooperative is keeping up with the times. Read More
Citrus
February 3, 2016
Syngenta OKs Buyout By ChemChina
Deal valued at more than $43 billion; Syngenta management team to stay intact. Read More
Farm Marketing
February 3, 2016
Florida Peach Marketing Order Fails
Growers don’t meet 65% approval needed for passage. Read More
Farm Management
February 3, 2016
Western Growers Launches Tech Talk Serie…
Speakers from a variety of agricultural technology areas will make presentations on a variety of topics including drone/satellite imagery and food safety software. Read More
Farm Management
February 3, 2016
Hot Topics Tackled At Mid-Atlantic Fruit…
Food safety and GMOs were two of the topics discussed on the first day of the trade show and conference. Read More
Citrus
February 3, 2016
Historic Rainfall Hampering South Florid…
El Niño express delivering floods, uncertainty for crops. Read More
Nuts
February 3, 2016
Avoid Tree Nut Cargo Theft
American Fruit Grower® and Western Fruit Grower® recently reported on a rash of nut thefts, in which truckloads of nuts Read More
Nuts
February 3, 2016
Tips To Help Secure A Good Beekeeper Agr…
Pollination is one of the most important aspects of almond growing, and this time of year, making sure you have Read More
Apples & Pears
February 2, 2016
Fine Americas Introduces Next Generation…
New formulation of Exilis 9.5 SC is five times more concentrated than previous product; it's also easier to pour, handle. Read More
[gravityform id="62" title="false" description="false"]