Chlorine works: Reducing Salmonella outbreaks in mangoes

The new crop of Australian mangoes is starting to arrive in spring-like Brisbane (because it’s more like summer with temps expected to hit 40 C this weekend), and they are delicious.

A team in one University of Connecticut lab recently processed 4,000 mangoes and water samples to test the efficacy of three disinfectants commonly used by the industry to avoid contamination.

To the utter surprise of researcher Mary Anne Amalaradjou, they found an unlikely candidate was extremely effective: chlorine. “When I saw the results, I didn’t believe it. So we re-ran the test ten times,” says the assistant professor in the Department of Animal Science.

Amalaradjou will present her findings at a meeting of the National Mango Board.

Salmonella is a frequent culprit for outbreaks in mangoes because it makes its way into the water used to wash the fruit in processing plants. According to the Centers for Disease Control and Prevention Salmonella leads to approximately 1.2 million cases of Salmonellosis each year in the United States and around 23,000 hospitalizations and 450 deaths.

“We had several outbreaks of people getting sick. The worrying part was the illnesses were not from cut mangoes, these were from mangoes they bought whole,” says Amalaradjou, whose work focuses on food safety and in finding new approaches to control or prevent foodborne illnesses.

In mango processing plants, the wash water is housed in gigantic tanks and once the water is contaminated, the bacteria are able to attach to the fruit’s skin and then enter the fruit’s pulp. Once bacteria make their way into the fruit, no amount of washing can remove them. With so many mangoes washed at once, the number of contaminated mangoes can be numerous, potentially causing many cases of Salmonellosis.

mango tropical fruit with male hand picking fruit from tree

Recognizing the danger, the Center for Produce Safety and the National Mango Board funded Amalaradjou’s study.  After taking on the project, Amalaradjou traveled to a mango processing plant to see the source of the contamination, the big wash water tanks, for herself in order to learn the processes so she could adapt them to a smaller-scale laboratory set up.

Amalaradjou was surprised by the results because chlorine is not very effective in the wash step for most produce. For one reason or another, from lettuce, to tomatoes to apples, chlorine simply doesn’t reliably kill Salmonella.

With mangoes, Amalaradjou found, chlorine cleaned the wash water and also helped prevent cross-contamination by cleaning the mangoes themselves.

One of the other challenges the research group had to tackle was not only effective Salmonella killing, but doing so with affordable and easily implementable measures on a large scale. Because chlorine is already used in the wash water, all that the processing plants need to do is to monitor the levels frequently to keep it at an effective concentration.

Chlorine is your friend, but chlorinating water in Christchurch’s northwest is off the table

As the third case of Guillain-Barre Syndrome has been linked to the Campylobacter contamination of Havelock North’s water supply, New Zealand, chlorinating water in Christchurch’s northwest is off the table, for now.

eight_col_1m1a9865The Christchurch City Council went against its own staff advice and unanimously decided on Thursday not to consider temporarily chlorinating the water from eight shallow wells that feed into three pump stations, serving about 20,000 residents.

The council instead decided to accelerate a $16 million programme to replace 22 shallow bores, supplying 80,000 northwest households.

The work was originally due to be finished by June 30, 2018, but most of the wells would now be decommissioned by March 2017. Fourteen of the most vulnerable shallow wells have already either been decommissioned or shut down.

Accelerating the work would cost an additional $480,000.

The council would also embark on a programme to raise community awareness of the risks of drinking untreated water from the shallow bores.

Canterbury’s medical officer of health, Alistair Humphrey, last month asked the council to explain why its continued use of the shallow wells did not present “an untenable risk”. Humphrey’s request was prompted by a gastro outbreak caused by campylobacter in the water supplying the town of Havelock North in Hawke’s Bay.

Staff will now talk to Humphrey to see if he was satisfied with the council’s response, without chlorinating the water. They will report back to the council in November.

Water from the bores was tested for E.coli daily, but it took at least 24 hours to get the results, so there was always a 24-hour period where contamination could go undetected, council three waters and waste boss John Mackie said.

He said the council complied with the water standards, but his professional advice to the council was to chlorinate the water, which would eliminate the risk.

Mayor Lianne Dalziel asked Mackie if the risk from the shallow bores had changed in the last few years. He said no.

She said it was only the perception of risk that had been heightened since the Havelock North contamination.

 

Chlorine is good: 4100 sick from NZ water, mayor says chlorination ‘will get a bloody good fight from us’

While his neighbours still suffer from the country’s worst case of mass water contamination, Napier Mayor Bill Dalton says his city will fight to keep chlorine out of its town supply.

bill.daltonLower Hutt Mayor Ray Wallace is also rejecting calls for all town water supplies to be chlorinated in the wake of the Havelock North contamination crisis.

About 74,000 Lower Hutt residents from Pomare to Petone drink chlorine-free water sourced from the Waiwhetu aquifer. The rest of greater Wellington’s supply is chlorinated.

In Hawke’s Bay, Napier, Hastings and Havelock North’s town supplies have been chlorine-free but the chemical was added to Havelock North water to treat a campylobacter contamination on August 12, and to the Hastings supply as a precaution last week.

Water treatment engineer Iain Rabbitts said chlorination should be made mandatory to avoid a repeat of the Havelock North crisis, adding, “We knew this was going to happen at some point in one of the unchlorinated supplies in New Zealand and we all hoped it wouldn’t be too bad.”

But Dalton said Napier would resist a move to mandatory chlorination “incredibly strongly because one of the points of difference of Napier is our wonderfully pure, unadulterated water supply”.

He did not want the city serving up the type of chlorine-tainted water other cities, such as Auckland, had to endure, he said.

dumbass“The first thing we do when we’re heading north is we pick up heaps of bottles of water because we don’t drink the water up in Auckland because it bloody stinks.

“If the Government turns around and tries to play the heavy hand, then they’ll get a bloody good fight from us.”

The only thing bloody about this scenario are the asses of the sick from constant pooping.

Marty Sharpe of Stuff also writes it now appears all but certain that a routine test of the Havelock North water supply showed it was clear of E.coli when it cannot have been.

The same test procedure is used by councils around the country, and its apparent failure in Havelock North may result in a reappraisal of whether current testing standards are robust enough.

Those questions are likely to form part of the government inquiry into the outbreak, announced on Monday.

Hawke’s Bay District Health Board chief executive Kevin Snee said on Monday that a survey of the 4500 residents affected by the campylobacter outbreak revealed they were most probably first exposed to the bug through their drinking water about Saturday, August 6, and that their symptoms first started showing on Monday, August 8.

But a routine test by Hastings District Council of the water supply on Tuesday, August 9, came back clear, showing no sign of E.coli. The test takes 24 hours, so the results came on Wednesday.

If they had shown positive at that point, the water system would have been chlorinated immediately.

The next routine test, on Thursday, August 11, came back on Friday as positive for E.coli. By that stage it was clear from DHB records that there was widespread illness in the area, and the decision was made to chlorinate.

E.coli, a common gut bacterium in warm-blooded animals, is used as an indicator of the contamination of water by excrement. It indicates there may be other pathogenic bacteria such as campylobacter.

Public Health Services drinking water assessor Peter Wood, who is in Hawke’s Bay working on the outbreak, said there could be situations of “sheer dumb luck” when E.coli was present in the water but not detected.

It’s called a chlorine monitor: If you wash fresh produce, buy one

Maintaining effective sanitizer concentration is of critical importance for preventing pathogen survival and transference during fresh-cut produce wash operation and for ensuring the safety of finished products. However, maintaining an adequate level of sanitizer in wash water can be challenging for processors due to the large organic load in the wash system.

tomato.dump.tankIn this study, we investigated how the survival of human pathogens was affected by the dynamic changes in water quality during chlorine depletion and replenishment in simulated produce washing operations. Lettuce extract was added incrementally into water containing pre-set levels of free chlorine to simulate the chlorine depletion process, and sodium hypochlorite was added incrementally into water containing pre-set levels of lettuce extract to simulate chlorine replenishment. Key water quality parameters were closely monitored and the bactericidal activity of the wash water was evaluated using three-strain cocktails of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes. In both chlorine depletion and replenishment processes, no pathogen survival was observed when wash water free chlorine level was maintained above 3.66 mg/L, irrespective of the initial free chlorine levels (10, 50, 100 and 200 mg/L) or organic loading (chemical oxidation demand levels of 0, 532, 1013 and 1705 mg/L). At this free chlorine concentration, the measured ORP was 843 mV and pH was 5.12 for the chlorine depletion process; the measured ORP was 714 mV and pH was 6.97 for the chlorine replenishment process.

 This study provides quantitative data needed by the fresh-cut produce industry and the regulatory agencies to establish critical operational control parameters to prevent pathogen survival and cross-contamination during fresh produce washing.

 Inactivation dynamics of Salmonella enterica, Listeria monocytogenes, and Escherichia coli O157:H7 in wash water during simulated chlorine depletion and replenishment processes

Food Microbiology, Volume 50, September 2015, Pages 88–96

Bin Zhou, Yaguang Luo, Xiangwu Nou, Shuxia Lyu, Qin Wang

http://www.sciencedirect.com/science/article/pii/S0740002015000556

Norovirus disinfection: How much is enough?

There’s common sense, and then there’s evidence-based.

Show me the evidence.

Science Daily reports a variety of institutions and governments have developed “commonsense-based” disinfection guidelines to control norovirus contamination, but now, for the first time, a Dutch team has come up with science-based guidelines.

The research is published in the November 2012 issue of the journal Applied and Environmental Microbiology.

Norovirus is the most common cause of gastroenteritis, according to the Centers for Disease Control and Prevention (CDC). This fecal-orally transmitted virus is notorious for spreading like wildfire in schools, on ocean cruises, and where-ever one infected person may be involved in the feeding of hundreds more, leaving victims tossing their cookies for as long as several days. Norovirus is especially problematic when it strikes hospitals, as both staff and patients are laid low.

In the study the researchers first determined how low the concentration of virions needed to go for transmission to become unlikely. They then tested different methods of cleaning hard surfaces, by using water, soap, or chlorine bleach solutions to determine the best method, or combination of methods for achieving a sufficiently low concentration to prevent virus transmission from hard surfaces, such as your kitchen counters.

The researchers prescribe a two-step process: wipe with a wet cloth, and then disinfect with chlorine. Their prescription is directed at hospitals, schools, restaurants, and other food-handling establishments. In most cases, a 250 ppm solution of chlorine is sufficient, but for high levels of contamination, they recommend 1,000 ppm, says principal investigator Erwin Duizer, of the National Institute for Public Health and the Environment, Bilthoven, the Netherlands.

To achieve 1,000 ppm, one Suma Tab D4 tablet must be dissolved in 1.5 liters of water (about a quart and a half). Household bleach, says Duizer, is an average about 5 percent chlorine when new (concentration declines with age), or 50,000 PPM, and thus, can be diluted 50-fold to achieve the 1,000 ppm.

Norovirus is apparently no more resistant to cleaning and disinfection than other pathogens, says Duizer. The virus’ efficiency in causing outbreaks “is more likely due to their extremely low infectious dose,” resulting in the requirement of a very low level of residual contamination in order to prevent further transmission. “Fortunately, reducing the level of residual contamination to that low level is not that difficult and can be achieved without extreme measures,” says Duizer.

“The current guideline for norovirus outbreaks in the Netherlands is quite stringent in some aspects,” says Duizer. “During recent years I have heard many complaints from people in the field that ‘it just can’t be done.'” The new guidelines will be more practical, and thus more effective, he says.

Journal Reference:

E. Tuladhar, W. C. Hazeleger, M. Koopmans, M. H. Zwietering, R. R. Beumer, E. Duizer. Residual Viral and Bacterial Contamination of Surfaces after Cleaning and Disinfection. Applied and Environmental Microbiology, 2012; 78 (21): 7769 DOI: 10.1128/AEM.02144-12

 

Going public: Iowa law shields targets of norovirus probe

In March 2012, dozens of people were apparently sickened with norovirus after visiting an eastern Iowa swim facility.

The Quad-City Times has been trying to name the facility, but an Iowa law allows public health officials to keep secret the name of a business involved in a disease investigation; this, say some of those sickened, puts business interests before public safety.

Johnson County and state health officials won’t release the name of the facility despite dozens being sickened, citing state law that shields businesses that have cleaned up their act after an outbreak. They also believe there is no ongoing public health risk.

“I just wish the name would be out there, so others could know about this happening at a family attraction,” said Courtney Evans of Blue Grass, Iowa. Evans’ two young boys and her husband fell ill from norovirus after a visit to the swim facility.

The Quad-City Times and The Gazette of Cedar Rapids jointly filed a complaint with the Iowa Office of Citizens’ Aide about the health department’s refusal to release the name of the swim facility or provide key details about the investigation, such as dates of when people got sick. The Citizens’ Aide ruled public health officials followed the law.

“The problem is that I have to obey the law,” said State Epidemiologist Patricia Quinlisk. “If people feel that is incorrect, they have to talk with their legislators (about changing the law).”

Some Iowa legislators say the current law might go too far.

“We have a duty to inform the public that this has occurred and that it’s been remedied,” said Rep. Rick Olson, D-Des Moines. “I want to keep my kids healthy.”

Rep. Vicki Lensing, D-Iowa City, said the public needs accurate information from the health department, not speculation. “It would seem like after an investigation is concluded that information could be released,” she said.

Records obtained by the Quad-City Times and the Gazette through an Open Records request with the Johnson County Public Health Department indicate more than 30 people contracted norovirus after visiting the swim facility in March. Johnson County, which handled the facility investigation, inspects pools in Johnson, Iowa, Louisa and Muscatine counties.

“Early this morning, all family members began vomiting and have experienced diarrhea,” states a Johnson County record-of-contact form. The complainant “contacted the family members they traveled with, and all are experiencing the same symptoms.”

“…the complainant believes that illnesses derived from exposure to pool water. The two individuals that did not enter the pool water have not become sick,” the report shows.

According to the records, which include handwritten notes, reports and emails, chemical tests leading up to the outbreak showed the pools had little or no chlorine, which kills pathogens that can cause disease. Pool management told officials a chlorine feeder was plugged.

Iowa Code Section 139A.3 states “information contained in the report may be reported in public health records in a manner which prevents the identification of any person or business named in the report.” This means public health officials can tell the public about the outbreak only in a generic way that doesn’t identify the business.

Before Quinlisk decides to keep investigation details secret she asks herself one question: Would she take her own child to the facility?

In this case, the answer was yes, she said.

Not every state gives businesses the same protection as individuals when it comes to disease reports. Minnesota, for example, only keeps the health records of individuals private, not businesses.

“If we have an outbreak at Joe’s Diner, that’s public,” said Richard Danila, deputy Minnesota epidemiologist.

The Illinois Department of Public Health has a policy to keep confidential the name of a business involved in a disease investigation, but the information can be obtained through open records requests after the investigation is concluded, said Department spokeswoman Melaney Arnold.

An accompanying editorial says several Quad-City area families sickened by the virus contacted us and were referred by Scott County health officials to the Johnson County Health Department in late March. We followed up, pursuing public records to confirm the account.

We were not seeking the names of the victims. The victims came to us. They spoke on the record.

So, yes, we know what business was investigated.

But we need public officials verifying the investigation to be able to report this responsibly and without fear of liability from a possible lawsuit since the origin of the norovirus has not been proven, the business complied with orders to take corrective action, and there was no perceived ongoing public health risk.

If I wanted to take my child to the facility, I would want to know their track-record and whether they could adequately manage things like chlorine levels, or whether I should bring my own pH strips.

Just like I want to know the track record of a restaurant before I spend my money there.

Listeria-linked farm had rated high in third-party audit

Chlorine is a wonderful thing when it comes to sanitation; especially with fresh produce. It’s also necessary to control dangerous bacteria, so it’s mind-numbing to hear a leading third-party auditor say that, based on the recommendations of staff who are supposed to know about food safety, that water does not have to be treated with something like chlorine.

Elizabeth Weise of USA Today reports that Jensen Farms, whose listeria-laden cantaloupes have killed 26 and sickened at least 123, got a top score — 96% — from a firm auditing the plant’s sanitation practices six days before the first person fell ill.

The rating has once again helped raise questions about the credibility of so-called third-party audits, a practice used increasingly by food sellers who hire auditing companies to check the safety and sanitation of the firms that sell them products and ingredients.

The Primus audit also gave only a mention to a change in how the fruit was washed, though one of the nation’s foremost cantaloupe safety experts, Trevor Suslow, calls it "unacceptable" and a clear violation of current industry practices.

Suslow, an expert on the post-harvest handling of produce at the University of California-Davis, said he was rendered "speechless" at news that Jensen was using untreated water to wash its melons.

The problem, which Suslow called a "red flag," was a switch by Jensen to a new fruit-washing system in July 2011. According to the FDA report and Gorny, that month Jensen Farms purchased and installed a used potato-washing machine to wash its cantaloupe.

According to the audit done by Primus Labs in August 2010, it appears that Jensen Farms had previously used a "hydro cooler" system to wash and cool the melons as they came in from the field, using recirculated water that was treated with an anti-microbial to kill bacteria.

For the 2011 harvest, the farm switched to a system in which cantaloupes were washed with fresh water that was not recirculated and "no anti-microbial solution is injected into the water of the wash station," the auditor, James DiIorio, noted on the first page of his audit.

"You would flat-out never do that, absolutely not," said Suslow, who spent more than six years researching cantaloupe safety and handling. No matter how clean the source of water is, once it’s sprayed on "any kind of surface where you have multiple produce items rolling across it, you’re trying to prevent cross-contamination … so you always add something to the water."

Suslow called this a "fundamental error with just tragic consequences. We can’t know that it absolutely made a difference, but I honestly think it could have prevented the scale and scope of what happened."

Robert Stovicek, president of Primus Labs, defended the audit, saying requiring that the wash water be treated with an anti-microbial is not "industry standard" at this time. He said his auditor, who so far has done 86 audits for Primus, did a good job in that he noted on page one of the audit that untreated water was being used. "He didn’t score them down but he commented on it," Stovicek said.
Audit companies do not set standards, he said. "We’re a company out there making observations and recording them."

Suslow and others disagree. Jensen Farms was "relying on people they consider knowledgeable and expert — that’s why they’re paying them," Suslow said.

Stovicek said that putting an anti-microbial agent such as chlorine in the water "certainly would retard any kind of spread. I think Trevor’s right to question that." But the Jensen Farms staff believed they were making an improvement in the safety when they switched to their new system. After the outbreak came to light, Stovicek consulted with his staff and they told him that water that’s not recirculated isn’t required to be treated. "I think Jensen’s will now go to sleep every night for the rest of their lives thinking, ‘Would that have made a difference?’"

The problems that were found at Jensen Farms are "Packing House 101," said Stephen Patricio, chairman of the California Cantaloupe Advisory Board. "Every common surface must be cleaned, rinsed and sanitized," he said. "These are all just known, recognized practices."

"It’s just disgusting to me," Patricio said of both Jensen Farms and Primus Labs. "I think of the damage that they’ve done to our industry as the result of this oversight. No, I won’t even talk about it as oversight, it’s abuse."

Walkerton 11 years later; E. coli O157:H7 in a municipal water supply

On Sunday, May 21, 2000, at 1:30 p.m., the Bruce Grey Owen Sound Health Unit in Ontario, Canada, posted a notice to hospitals and physicians on their web site to make them aware of a boil water advisory for Walkerton, and that a suspected agent in the increase of diarrheal cases was E. coli O157:H7.

Not a lot of people were using RSS feeds, and I don’t know if the health unit web site had must-visit status in 2000. But Walkerton, a town of 5,000, was already rife with rumors that something was making residents sick, and many suspected the water supply. The first public announcement was also the Sunday of the Victoria Day long weekend (which happens this weekend in Canada) and received scant media coverage.

It wasn’t until Monday evening that local television and radio began reporting illnesses, stating that at least 300 people in Walkerton were ill.

At 11:00 a.m., on Tuesday May 23, the Walkerton hospital jointly held a media conference with the health unit to inform the public of outbreak, make the public aware of the potential complications of the E. coli O157:H7 infection, and to tell the public to take necessary precautions. This generated a print report in the local paper the next day, which was picked up by the national wire service Tuesday evening, and subsequently appeared in papers across Canada on May 24.

The E. coli was thought to originate on a farm owned by a veterinarian and his family at the edge of town, a cow-calf operation that was the poster farm for Environmental Farm Plans. Heavy rains washed cattle manure into a long discarded well-head which was apparently still connected to the municipal system. The brothers in charge of the municipal water system for Walkerton were found to add chlorine based on smell rather than something like test strips, and were criminally convicted.

Ultimately, 2,300 people were sickened and seven died. All the gory details and mistakes and steps for improvement were outlined in the report of the Walkerton inquiry, available at http://www.attorneygeneral.jus.gov.on.ca/english/about/pubs/walkerton/.

Today, as the 11th anniversary of the Walkerton outbreak approaches, Canadian Press reports the Ontario government has paid out more than $72 million in compensation to victims of Walkerton’s tainted water tragedy and their families.

Ontario Attorney General Chris Bentley says over 99 per cent of the more than 10,000 compensation claims have been resolved, and the remainder are supposed to be resolved by the end of this year.

A total of 10,189 claims were made, with 9,275 qualifying for compensation.
Bentley says while nothing will ever make up for the tragedy experienced in Walkerton, he hopes the compensation plan has helped all those who suffered continue along the path to healing.

Among the 121 recommendations on an inquiry aimed at preventing a recurrence of the public-health disaster were ones geared toward mandatory training and certification for water-system operators.

7 sick from Campylobacter in Utah well water

First raw milk, now the water in Utah is making people sick.

The Salt Lake City Tribune reports that a boil-water advisory will remain in effect for residents of Northern Saratoga Springs (right, exactly as shown) after at least seven people were stricken by Campylobacter.

Saratoga police spokesman Cpl. Aaron Rosen said the city is awaiting test results on a well believed to be the source of a campylobacter outbreak in the city. The city is treating the water with chlorine to kill the bacteria.

Mount Olympus Waters dispatched a 6,000-gallon tanker truck to provide free water for residents. The tanker is parked at Walmart, at Redwood Road and State Route 73.

Larry Mullenax, Mount Olympus vice president, said the company will provide two one-gallon containers of water per person. But if people bring their own containers, the company will fill them for free.

Walmart employees are staffing the tanker from 8 a.m. to 8 p.m., he said.

Questioning food safety practices

Health inspectors or like our partners to the South, registered sanitarians need to keep abreast of evidence based food safety publications to provide the most accurate and up to date information to the public. It is apparent that regulatory bodies tend to push certain food safety practices without them ever be questioned. For instance, are chemical sanitizers really the best way to go in terms of bacterial log reductions on food contact surfaces? Restaurant inspectors constantly push for the use of chlorine or quaternary ammonia as the chemicals of choice for sanitation. Yes, they do work, but what about vinegar. I read an interesting article from Pete Snyder comparing quaternary ammonia, vinegar, and water on cutting boards1. The paper states wiping a surface with a clean cloth soaked in vinegar is a very effective sanitizer. Furthermore, that vinegar should be approved as a sanitizer for food contact surfaces.
One critical item that restaurant inspectors take note of is whether or not an establishment is using an approved sanitizer. Half of the time there is no sanitizer, but when there is, the concentration tends to be too strong i.e. >500 ppm available chlorine. Other times, the sanitizer solution is often mixed with a detergent rendering it ineffective. Restaurant inspectors need to take the time to check these critical control measures to ensure the restaurant operator is aware of these issues. A simple 5-7 minute inspection certainly will not suffice and in my opinion is a grand waste of time. That’s like making a fantastic, time worthy meal, and wolfing it down in minutes instead of enjoying it. I’m Italian, I enjoy food.
 
KGBT 4 reports:
 
Noe’s Restaurant on 190 West Robertson in San Benito has a lengthy history on Food 4 Thought. The first dirty dining report we exposed at the location dates back to 2005 with 36 demerits. Noe’s scored 33 demerits back in December of 2009.   That’s why the food patrol looked a little closer at the restaurant’s latest inspection report when it was discovered Noe’s scored zero demerits.
At the top of each health report, an inspector is supposed to log the start and end times to complete each report. Noe’s inspection was finished in just seven minutes.   San Benito’s Code Enforcement Director, John Rodriguez Jr., admitted seven minutes was an “improper” time. He said it should have taken a minimum of thirty minutes to do a proper, thorough check of all 27 critical items established by the state.
 
1.Snyder, Peter. The Microbiology of Cleaning and Sanitizing a Cutting Board. Hospitality Institute of Technology and Management, 1997.