Tag Archives: metrics

Floodwater, E. coli and leafy greens

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The California Leafy Green Products Handler Marketing Agreement (LGMA) requires leafy green crops within 9 m of the edge of a flooded field not be harvested due to potential contamination (California Leafy Green Products Handler Marketing Board, Commodity Specific Flood Safety Guidelines for the Production and Harvest of Lettuce and Leafy Greens, 2012). Further, previously flooded soils should not be replanted for 60 days.

lettuceIn this study, the suitability of the LGMA metrics for farms in the Mid-Atlantic region of the United States was evaluated. The upper end of a spinach bed (in Beltsville, MD) established on a −5% grade was flooded with water containing 6 log CFU/ml Escherichia coli to model a worst-case scenario of bacterial movement through soil. Escherichia coli prevalence in soil and on foliar tissue was determined by most probable number (MPN) analysis at distances up to 9 m from the edge of the flood for 63 days. While E. coli was quickly detected at the 9-m distance within 1 day in the spring trial and within 3 days in the fall trial, no E. coli was detected on plants outside the flood zone after 14 days. On day 63 for the two trials, E. coli populations in the flood zone soil were higher in the fall than in the spring. Regression analysis predicted that the time required for a 3-log MPN/g (dry weight) decrease in E. coli populations inside the flood zone was within the 60-day LGMA guideline in the spring but would require 90 days in the fall. Overall, data suggest that the current guidelines should be revised to include considerations of field and weather conditions that may promote bacterial movement and survival.

Metrics proposed to prevent the harvest of leafy green crops exposed to floodwater contaminated with Escherichia coli

Appl. Environ. Microbiol. July 2016 vol. 82 no. 13 3746-3753, DOI: 10.1128/AEM.00052-16

Mary Theresa Callahan, Shirley A. Micallef, Manan Sharma, Patricia D. Millner, Robert L. Buchanan

http://aem.asm.org/content/82/13/3746.abstract?etoc

‘If there’s a cow within the next galaxy, they’re not going to buy;’ tomato growers frustrated with audit fatigue, ‘shower science’

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Doug Ohlemeier of The Packer revisits an early Feb. 2012 meeting of tomato growers, shippers, repackers, buyers, regulators and auditors in Florida to pull out a few golden quotes.

Billy Heller, chief executive officer of Pacific Tomato Growers Ltd., Palmetto, Fla., expressed disappointment with what he calls “shower science,” the protocols auditors and customers come up with that may not be practical.

“The differentiation is that someone as a customer says they’re going to be different and will say if there’s a cow within the next galaxy, they’re not going to buy. I can live with almost all of it, but not the ‘shower thoughts.’ It shouldn’t be in there if they’re not supported by science. Opinions don’t work.”

In a discussion about birds roosting on electric poles near tomato field bins, Heller said Florida growers must deal with a variety of wildlife, including lizards and alligators.

If auditors regulate how close wildlife can be to fields, it should be a science-based rule, he said.

Drew McDonald, Salinas, Calif.-based vice president of quality and food safety for Danaco Solutions LLC, Highland Park, Ill., said each circumstance is different.

“What we don’t want to do is throw the baby out with the bath water and remove all poles and eliminate all birds. I’m not exaggerating when I say we had a customer saying there’s too much dirt (in the field). We can get a little crazy here but these are common-sense things. People agree they don’t want bird droppings on fresh produce, but what they disagree on is ways to prevent that.”