Minnesota’s bad year of Salmonella, great year of surveillance

Posted on February 28, 2016 by Douglas Powell

In 2015, Minnesota counted 973 people with state-confirmed Salmonella, the most since health officials started tracking in the early 1990s. Cases were up 35 percent over 2014, according to the Minnesota Department of Health, with 115 people affected by the outbreak linked to Chipotle.

“It was a huge outbreak, the biggest salmonella outbreak [in this state] since 1994,” said Kirk Smith, the health department’s head of foodborne disease investigations.

The Chipotle case, along with a huge national outbreak last year involving cucumbers, highlights a growing problem: the spread of foodborne disease through produce.

Tomatoes connected to the Chipotle outbreak were traced back to a farm in Virginia, a big tomato-growing area linked to several salmonella outbreaks in the past 15 years.

Chipotle, hit by a series of foodborne illness outbreaks last year, did not return calls for comment.

Chipotle was cooperative in Minnesota’s investigation, Smith said, and analyzed its own supply chain data to determine that tomatoes linked to the outbreak likely came from a farm in Virginia.

According to the health department, the tomatoes were sold by Lipman Produce, an Immokalee, Fla.-based company that on its website bills itself as North America’s largest open field tomato grower.

Lipman’s CEO didn’t respond to requests for comment, but in a response to a lawsuit, the company denied that it was the source of the outbreak in Minnesota.

The Virginia tomatoes were sold to a produce wholesaler that packed or repacked them, and then moved on to a distributor that delivered them to Chipotle. Where exactly the tomatoes were tainted has not been identified, and the U.S. Food and Drug Administration (FDA) says it’s investigating.

Smith and other foodborne illness experts say contamination of produce usually occurs in unsanitary packing houses or in the fields, particularly through contaminated water.

From 1990 to 2010, there were 15 multistate salmonella outbreaks linked to raw tomatoes; four were traced to farms or packing houses in Virginia.

Virginia’s tomato industry is centered on its eastern shore, a peninsula framed by Chesapeake Bay and the Atlantic Ocean. Its gull and geese populations have been fingered as possible carriers of salmonella, as have chicken farms and processors to the north.

Whatever the reason, surface water and sediment in the area appear to be “long-term reservoirs of persistent and endemic contamination of this environment,” according to a study published last year in Frontiers in Microbiology.

The largest U.S. foodborne incident in 2015 was a Salmonella Poona outbreak that sickened 888 people nationwide, killing six. That outbreak included 43 illnesses in Minnesota, though no deaths.

The culprit: cucumbers imported from Mexico. It was the third significant U.S. outbreak of salmonella linked to cucumbers in three years.

E. coli and Salmonella in tomatoes

Posted on November 8, 2015 by Douglas Powell

Salmonella serovars have been associated with the majority of foodborne illness outbreaks involving tomatoes, and E. coli O157:H7 has caused outbreaks involving other fresh produce.

Contamination by both pathogens has been thought to originate from all points of the growing and distribution process. To determine if Salmonella serovar Typhimurium and E. coli O157:H7 could move to the mature tomato fruit of different tomato cultivars following contamination, three different contamination scenarios (seed, leaf, and soil) were examined. Following contamination, each cultivar appeared to respond differently to the presence of the pathogens, with most producing few fruit and having overall poor health.

The Micro-Tom cultivar, however, produced relatively more fruit and E. coli O157:H7 was detected in the ripe tomatoes for both the seed- and leaf- contaminated plants, but not following soil contamination. The Roma cultivar produced fewer fruit, but was the only cultivar in which E. coli O157:H7 was detected via all three routes of contamination. Only two of the five cultivars produced tomatoes following seed-, leaf-, and soil- contamination with Salmonella Typhimurium, and no Salmonella was found in any of the tomatoes. Together these results show that different tomato cultivars respond differently to the presence of a human pathogen, and for E. coli O157:H7, in particular, tomato plants that are either contaminated as seeds or have a natural opening or a wound, that allows bacteria to enter the leaves can result in plants that have the potential to produce tomatoes that harbor internalized pathogenic bacteria.

Movement of Salmonella serovar Typhimurium and E. coli O157:H7 to ripe tomato fruit following various routes of contamination

Microorganisms 2015, 3(4), 809-825

Deering, A.J.; Jack, D.R.; Pruitt, R.E.; Mauer, L.J.

http://www.mdpi.com/2076-2607/3/4/809

Salmonella on tomato leaves

Posted on November 1, 2015 by Douglas Powell

Thirty years ago, I was a graduate student inoculating different lines of tomatoes with Verticillium wilt.

I hated it.

So I became editor of the student newspaper.

But those plant pathogens and tomatoes are still embedded in my DNA, so when I see an abstract like this, I gotta send it out.

Plant pathogen infection is a critical factor for the persistence of Salmonella enterica on plants. We investigated the mechanisms responsible for the persistence of S. enterica on diseased tomato plants by using four diverse bacterial spot Xanthomonas species that differ in disease severities. Xanthomonas euvesicatoria and X. gardneri infection fostered S. enterica growth, while X. perforans infection did not induce growth but supported the persistence of S. enterica. X. vesicatoria-infected leaves harbored S. enterica populations similar to those on healthy leaves. Growth of S. enterica was associated with extensive water-soaking and necrosis in X. euvesicatoria- and X. gardneri-infected plants. The contribution of water-soaking to the growth of S. enterica was corroborated by an increased growth of populations on water-saturated leaves in the absence of a plant pathogen. S. enterica aggregates were observed with bacterial spot lesions caused by either X. euvesicatoria or X. vesicatoria; however, more S. entericaaggregates formed on X. euvesicatoria-infected leaves as a result of larger lesion sizes per leaf area and extensive water-soaking. Sparsely distributed lesions caused by X. vesicatoria infection do not support the overall growth of S. entericaor aggregates in areas without lesions or water-soaking; S. enterica was observed as single cells and not aggregates.

Thus, pathogen-induced water-soaking and necrosis allow S. enterica to replicate and proliferate on tomato leaves. The finding that the pathogen-induced virulence phenotype affects the fate of S. entericapopulations in diseased plants suggests that targeting of plant pathogen disease is important in controlling S. enterica populations on plants.

Plant Pathogen-Induced Water-Soaking Promotes Salmonella enterica Growth on Tomato Leaves

Applied and Environmental Microbiology, Volume 81, Number 23, December 2015

N Potnis, J Colee, J Jones, J Barak

64 sick: Tomatoes fingered as Salmonella source in Minnesota Chipotle outbreak

Posted on September 17, 2015 by Douglas Powell

As the number of Americans sick from Salmonella linked to Mexican cucumbers reached 418, tomatoes have been identified as the source of a Salmonella outbreak linked to Chipotle restaurants in Minnesota.

So much for the wife’s tomato and cucumber salad, with olive oil and salt.

The Minnesota Department of Health reports tomatoes have been identified as the source of the Salmonella Newport outbreak that has sickened dozens of people who ate at Chipotle restaurants in Minnesota since late August. Investigators are working with state and federal partners to trace the tomatoes back to the farm of origin.

Since the outbreak was reported last week, additional illnesses have been confirmed by MDH. A total of 64 cases and 22 locations now have been linked to the outbreak [locations are listed below]. Nine people have been hospitalized; all are recovering. Meal dates for the cases range from August 16 to August 28 and people became ill between August 19 and September 3. The cases range in age from 10 to 69 years and are from 13 metro counties and several greater Minnesota counties.

“We expected to see additional cases because it can take up to 10 days for symptoms of Salmonella to appear, another few days to a week before people go to their doctors and the cases get reported to us,” said MDH Epidemiologist Dana Eikmeier. “However, there is no longer a risk of Salmonella from this particular product at Chipotle.” The company has switched suppliers for its tomatoes and implicated product was removed from stores.

Food safety dominates first day of Florida tomato conference

Posted on September 9, 2015 by Douglas Powell

Doug Ohlemeier of The Packer writes that during the opening day of the Florida Joint Tomato Conference, participants heard how the state’s tomato good agricultural practices and tomato best management practices are helping ensure safe shipments.

Since implementation of TGAPS, tomatoes haven’t experienced any recalls or outbreaks, Keith Schneider, associate professor of Food Science and Human Nutrition with the Gainesville-based University of Florida’s Institute of Food and Agricultural Sciences, said during a Sept. 8 tomato safety session.

He also noted the Sept. 4 multi-state salmonella outbreak of Mexican cucumbers distributed by San Diego-based Andrew & Williamson Fresh Produce.

“All commodities are potential sources of foodborne illnesses,” Schneider said. “No one’s exempt. There is the recall in cucumbers for salmonella. Even things not traditionally associated with foodborne outbreaks (are subject to recalls). Those can be problematic. But I think we’re getting better with tomatoes and the record of tomatoes clearly speaks to that.”

In nine years of state tomato production inspections, the Tallahassee-based Florida Department of Agriculture and Consumer Services has issued 163 corrective actions, 120 failed audits and given 831 audit approvals, which means the farms and packinghouses passed the first time, said Steve Eguino, an agency certification specialist.

The average audit time is 3 1/2 hours and during the 2014-15 season, the agency conducted audits at 76 fields, five greenhouses, 81 packinghouses and 12 repacking operations, he said.

David Gombas, senior vce president of food safety and technology for the Washington, D.C.-based United Fresh Produce Association, said, “I’m getting tired of talking with folks that don’t have it. They did a mock recall last year with an auditor and think that’s enough, but it’s like deer in the headlights. It will always be more expensive doing it that way than having one in advance.”

Controlling Salmonella cross-contamination in tomatoes

Posted on July 19, 2015 by Douglas Powell

Tomato Best Management Practices require Florida packers to treat tomatoes in a flume system containing at least 150 ppm of free chlorine or other approved sanitizer.

However, research is needed to determine the ability of these sanitizers to prevent the transfer of pathogens from contaminated to uncontaminated tomatoes, particularly under realistic packinghouse conditions.

The goal of this research was to assess the minimum levels of sanitizer needed to prevent Salmonella cross-contamination between tomatoes in a model flume system under clean conditions and conditions where organic matter was added.

Inoculated tomatoes (ca. 8.3 log CFU per tomato) were treated along with uninoculated tomatoes in a model flume system containing 0, 10, or 25 ppm of hypochlorous acid (HOCl) under organic loading conditions of 0, 500, or 4,000 ppm of chemical oxygen demand (COD). In the absence of HOCl, uninoculated tomatoes were highly contaminated (ca. 5 log CFU per tomato) by 15 s. No contamination was detectable (<2 log CFU per tomato) on uninoculated tomatoes when HOCl was present, except with 10 ppm at 4,000 ppm of COD, suggesting failure of 10 ppm of HOCl as a sanitizer under very high organic loading conditions. In the presence of HOCl or peroxyacetic acid, Salmonella was undetectable (<1 log CFU/ml) in the model flume water samples after 2 and 30 s, respectively. Upon enrichment, none of the uninoculated tomatoes treated with 25 ppm of HOCl for 120 s were positive for Salmonella, even in the presence of organic loading at 500 ppm of COD. Based on these findings, 25 ppm of HOCl may be adequate to prevent cross-contamination when the concentration is properly maintained, COD does not exceed 500 ppm, and tomatoes are treated for at least 120 s.

Further validation in a larger commercial setting and using higher organic loading levels is necessary because managing HOCl at this low concentration is difficult, especially in a recirculating system. The use of less sanitizer by packers could reduce chemical and disposal costs.

Control of Salmonella Cross-Contamination between Green Round Tomatoes in a Model Flume System

Journal of Food Protection®, Number 7, July 2015, pp. 1250-1419

Gereffi, Scott, Sreedharan, Aswathy, Schneider, Keith R.

http://www.ingentaconnect.com/content/iafp/jfp/2015/00000078/00000007/art00006

As always, more research required: Study analyzes tomato production practices

Posted on January 17, 2015 by Douglas Powell

Doug Ohlemeier of The Packer writes that tomato production practices don’t significantly affect bacteria levels and the study’s results point to the need for additional research, according to University of Maryland and Rutgers University researchers.

That’s the conclusion of a study scheduled to be published in the March issue of the International Journal of Food Microbiology.

From July to September 2012, researchers from the College Park-based University of Maryland’s College of Agriculture and Natural Resources’ Center for Food Safety and Security Systems and New Brunswick, N.J.-based Rutgers’ Cooperative Extension collected and tested 422 samples from 24 conventional and organic tomato farms from four growing regions in Maryland, Delaware and New Jersey.

The researchers analyzed 259 tomato fruit samples and also examined irrigation water, compost, field soil and pond sediment for Salmonella enterica, shiga toxin and bacterial indicators in pre-harvest tomatoes.

They didn’t detect any salmonella on the farms and the prevalence of shiga toxin, a byproduct of E. coli, was very low, said Shirley Micallef, an assistant professor who heads the Maryland university’s food safety center and Plant Science and Landscape Architecture department.

One curious finding was an apparent difference in bacteria present on tomatoes that touch the ground vs. tomatoes higher in a vine canopy that don’t contact the plastic or straw mulch.

Researchers found indicator bacteria on the ones that connected with the ground but no pathogens, Micallef said.

That discovery doesn’t mean tomatoes that touch the ground shouldn’t be harvested but only points to the need for additional investigation, she said.

Another finding was groundwater from the end of drip lines possessed higher indicator bacteria counts than the source water, Micallef said.

The difference in microbiological quality of water signals potential risk and points to the need for growers to conduct more frequent drip line system maintenance by testing water at the end of the line, she said.

The research also found no difference in contamination risk between conventional and organic tomatoes and study was also different because it focused on small and medium-sized growers, Micallef said.

“It was encouraging we didn’t find a huge problem because here in the Mid-Atlantic, we have had outbreaks associated with tomatoes,” she said. “It’s good to see growers really paying attention to GAPs (good agricultural practices) and trying to implement food safety practices as best they can in the fields. They probably do help to reduce the risk.”

Mexican tomatoes Salmonella positive

Posted on October 11, 2014 by Douglas Powell

Fresh-cut roma tomatoes grown in Mexico and distributed to Costco by Boskovich Farms Inc. may have been contaminated with salmonella and are part of a voluntary recall Expo Fresh LLC initiated in September.

Coral Beach of The Packer reports Boskovich was not named in the Sept. 12 recall notice on the Food and Drug Administration’s website. However, the Oxnard, Calif., company and its diced roma tomatoes were included in the agency’s Oct. 7 weekly enforcement report.

No illnesses have been reported in connection to the tomatoes, according to the FDA. The recall was initiated after a routine sampling by government officials returned positive results for salmonella.

Local doesn’t mean safe; tales of tomato woes

Posted on September 26, 2014 by Douglas Powell

“I’ve been promoting local my whole life, but I’m thinking now that we may have shot ourselves in the foot. Michelle Obama asked us to grow gardens, and I believe everyone did.”

So say shippers like Gary Margolis, president of Boca Raton, Fla.-based Gem Tomato & Vegetable Sales Inc. in The Packer.

Then there’s what he and other big shippers throughout the produce industry call an uneven playing field when it comes to food safety.

“While the local guys are shipping under the food safety radar, our guys are swabbing their warehouses with toothbrushes,” Margolis said. “We have to jump through all these hoops, and they come in through the back door.”

Let’s hope it doesn’t take a food safety outbreak for the industry and the government to bring some more order to “local.”

Going public: Salmonella, tomatoes (not) and court

Posted on September 21, 2014 by Douglas Powell

Summer 2008 was adventurous for us: Amy was pregnant, we were in Quebec, and I was handling endless media calls about Salmonella in tomatoes that sickened at least 851 people in the U.S., including a sorta creepy middle-of-the-night chat fest for some radio station.

Turns out it was probably jalapeño peppers.

Tomato growers lost millions and decided to sue the U.S. government for going public prematurely.

Growers and others would be better served if there were clear, publicly available guidelines for when to go public about foodborne illness.

As reported by Michael Doyle of the Fresno Bee, a federal court has rejected the potentially far-reaching claims of Florida tomato growers who say they lost business because of Food and Drug Administration warnings.

The ruling unsettles numerous growers, who collectively lost several hundred million dollars following FDA food safety warnings in 2008 that proved erroneous. The ruling also curtails other growers tempted to base similar challenges on the constitutional requirement that the government pay compensation for taking property.

“Advisory pronouncements, even those with significant financial impact on the marketplace, are not enough to effect a taking of property under the Fifth Amendment,” U.S. Court of Federal Claims Senior Judge Lynn J. Bush stated.

In a 13-page decision quietly issued Thursday, Bush concluded that “although a wide range of government actions may give rise to regulatory takings,” these actions do not extend to “press releases and consumer advisories, by themselves.”

The Tallahassee, Fla.-based attorney representing the growers, M. Stephen Turner, said in an interview Friday that he will appeal. He likened the government’s actions to somebody who “stands in front of a house and says it’s infested with vermin,” thereby destroying property value.

The FDA had responded to an outbreak of salmonella-related illnesses in 2008, issuing warnings on June 3 and June 7 of that year linking the outbreak to certain types of tomatoes. The FDA also held a media briefing on June 13, opining that the “vast majority” of salmonella-tainted tomatoes was “very likely” from New Mexico and Florida.

Four days later, having concluded the disease outbreak was actually linked to imported serrano and jalapeno peppers, the FDA lifted its warning against tomatoes. In the meantime, though, “all or almost all of the value of plaintiffs’ perishable tomatoes was destroyed by the collapse in the market for tomatoes triggered by the FDA’s warnings,” Bush noted.

The price of Georgia tomatoes in 2008 dropped to less than $4 per box from the usual $18 to $19, while some Florida growers were reportedly reduced to selling their crop for less than $1 per box.

barfblog

safe food from farm to fork

Tag Archives: tomato