Diets rich in minimally processed foods are associated with numerous health benefits, in part, due to their diverse, natural microbiota. However, antimicrobials, such as chlorine and peracetic acid (PAA), that are used to address food safety concerns may damage the natural microflora of fresh produce.
One promising approach for targeting pathogenic bacteria in foods without impacting the normal food microbiota are bacteriophages. In this study, we observed that combinational treatment of conventional antimicrobials (PAA and chlorine) and bacteriophages, specifically the Salmonella‐targeted preparation SalmoFresh, retained the bactericidal effectiveness of individual interventions, and in some cases, achieved substantially increased efficacy. Additionally, the bacterial microbiomes of farm fresh and organic produce were less affected after phage treatment compared to PAA and chlorine.
Finally, our study revealed that resistance rates against SalmoFresh were relatively minor and unaffected by the stresses introduced after chemical washes and/or bacteriophage treatment.
Treatment of fresh produce with a salmonella-targeted bacteriophage cocktail is compatible with chlorine or peracetic acid and more consistently preserves the microbial community on produce, 10 January 2020
Nearly one-half of foodborne illnesses in the United States can be attributed to fresh produce consumption. The preharvest stage of production presents a critical opportunity to prevent produce contamination in the field from contaminating postharvest operations and exposing consumers to foodborne pathogens. One produce-contamination route that is not often explored is the transfer of pathogens in the soil to edible portions of crops via splash water.
We report here on the results from multiple field and microcosm experiments examining the potential for Salmonella contamination of produce crops via splash water, and the effect of soil moisture content on Salmonella survival in soil and concentration in splash water. In field and microcosm experiments, we detected Salmonella for up to 8 to 10 days after inoculation in soil and on produce. Salmonella and suspended solids were detected in splash water at heights of up to 80 cm from the soil surface. Soil-moisture conditions before the splash event influenced the detection of Salmonella on crops after the splash events—Salmonella concentrations on produce after rainfall were significantly higher in wet plots than in dry plots (geometric mean difference = 0.43 CFU/g; P = 0.03). Similarly, concentrations of Salmonella in splash water in wet plots trended higher than concentrations from dry plots (geometric mean difference = 0.67 CFU/100 mL; P = 0.04).
These results indicate that splash transfer of Salmonella from soil onto crops can occur and that antecedent soil-moisture content may mediate the efficiency of microbial transfer. Splash transfer of Salmonella may, therefore, pose a hazard to produce safety. The potential for the risk of splash should be further explored in agricultural regions in which Salmonella and other pathogens are present in soil. These results will help inform the assessment of produce safety risk and the development of management practices for the mitigation of produce contamination.
Salmonella survival in soil and transfer onto produce via splash events
December 2019
Journal of Food Protection vol. 82 no. 12
DEBBIE LEE,1 MOUKARAM TERTULIANO,2 CASEY HARRIS,2† GEORGE VELLIDIS,2 KAREN LEVY,1* and TIMOTHY COOLONG3
Human norovirus (HuNoV) is a foremost cause of domestically acquired foodborne acute gastroenteritis and outbreaks. Despite industrial efforts to control HuNoV contamination of foods, its prevalence in foodstuffs at retail is significant. HuNoV infections are often associated with the consumption of contaminated produce, including ready-to-eat (RTE) salads.
Decontamination of produce by washing with disinfectants is a consumer habit which could significantly contribute to mitigate the risk of infection. The aim of our study was to measure the effectiveness of chemical sanitizers in inactivating genogroup I and II HuNoV strains on mixed salads using a propidium monoazide (PMAxx)-viability RTqPCR assay. Addition of sodium hypochlorite, peracetic acid, or chlorine dioxide significantly enhanced viral removal as compared with water alone. Peracetic acid provided the highest effectiveness, with log10 reductions on virus levels of 3.66 ± 0.40 and 3.33 ± 0.19 for genogroup I and II, respectively. Chlorine dioxide showed lower disinfection efficiency.
Our results provide information useful to the food industry and final consumers for improving the microbiological safety of fresh products in relation to foodborne viruses.
Effectiveness of consumers washing with sanitizers to reduce human norovirus on mixed salad
Eduard Anfruns-Estrada, Marilisa Bottaro, Rosa Pinto, Susana Guix, Albert Bosch
Tom Karst of The Packer writes that teasing the details of a new era of smarter food safety, Food and Drug Administration deputy commissioner for food policy and response Frank Yiannas spoke Sept. 18 at the United Fresh Washington Conference.
Before coming to FDA last December, Yiannas was vice president of food safety at Walmart from 2008 to 2018.
And Disney in Orlando before that.
Yiannas said the FDA’s work on produce safety has been front and central to his work since he joined the agency.
He praised the industry for its contribution to food safety and said the public-private partnership on food safety efforts must strengthen even more in what he called a new era of smarter food safety that is set to begin in 2020.
“I was asked by the Commissioner to continue to lead our efforts on modernization,” Yiannas said. “We’ve come a long way since 2011, but there’s still work to be done.”
Tech-enabled traceability and tech-enabled outbreak response will be one area of focus for the new era of smarter food safety, Yiannas said.
While produce has an impressive safety record overall, he said there are weak points in the supply chain.
“What I have learned over the years, and especially from my vantage point with the world’s largest company, is that I do believe the food system’s Achilles heel is traceability and transparency,” he said.
He noted that in both the spinach-related foodborne illness outbreak in 2006 and the romaine-related outbreak in 2018, traceability was an issue.
“It seems eerily similar almost a decade later,” he said. “And we still are having to do these overly broad consumer advisories.”
Distributed ledger or blockchain technology can be part of the solution, he said, but that isn’t the focus.
“It is not about the technology— it is about solving some of our many public health challenges,” he said.
Helping efforts to create a culture of food safety among growers, food marketers, and consumers is another element of the new era plan, he said.
“What I’ve learned over the years, is that it’s impossible to make progress without changing and influencing behavior,” he said, noting the importance of “digital prompts” to encourage right behavior.
All washing might do is “remove the snot that some 3-year-old blew onto the food at the grocery store,” says the ever-forthright Powell at Kansas State. Washing “lowers the pathogen count a little, but not to safe levels if it’s contaminated.”
I said that in a Feb.15, 2012 interview with USA Today.
And a coupe of days ago a former MS student and friend sent me this:
Tom Karst of The Packer writes U.S. growers are using less risky irrigation sources and are sanitizing their equipment more often than 20 years ago.
Geez that’s about how long my group was doing on-farm food safety and looking at those exact questions.
Guess on-farm food safety is just a John Prine song.
Those observations are part of a new study called “Changes in U.S. Produce Grower Food Safety Practices from 1999 to 2016,” authored by economists Gregory Astill, Travis Minor and Suzanne Thornsbury.
“Since 1999, and before the implementation of U.S. Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption, the share of growers who use practices that reduce the risk of microbial contamination increased,” the study concluded.
The study said fewer growers use flowing surface water for irrigation and more growers use well water. As organic production has increased over time, the study found that more growers use manure and compost. And while more growers’ fields are next to livestock, the authors said more growers use fencing around production areas.
“The most prominent example of change is the increase in frequency that growers and sanitize harvest tools,” the study said. “The decrease in growers who never wash harvest tools is drastic as is the decrease in those who never sanitize.”
Even with the increase in food safety practices, the study said more needs to be done.
“The data available for this article also demonstrates a real need to implement more frequent measures of food safety practices within this rapidly evolving industry,” the authors said.
The agribusiness program Goldberg developed in 1955 continues to bring business leaders and policy makers from around the world together each year. Throughout his tenure, Ray has written over 100 articles and 24 books on the business of agriculture, including his very latest, Food Citizenship: Food System Advocates in an Era of Distrust.
He was interviewed by podcast host, Brian Kenny: Did you coin the term agribusiness?
Ray Goldberg: I did, together with John Davis. He was the Assistant Secretary of Agriculture under Eisenhower, and he became the first head of the (HBS) Agribusiness Program.
Brian Kenny: The case cites examples of foodborne illness outbreaks in the US. We’re coming on the heels of the recent romaine lettuce issue in the US, which has now occurred, I think, twice in the last few months.
Ray Goldberg: I can describe the romaine lettuce [event], because I talked to the produce manager this morning, and he tells me the cost to the industry was $100 million dollars.
The problem is that romaine lettuce itself, when cold temperatures occur, begins to blister, which make it more susceptible to listeria. When they tried to find the location of that listeria, it came from a dairy herd about 2,000 feet away from where that lettuce was grown. We have a rule that 1,200 feet is far enough, but they actually found listeria a mile away from where that lettuce was concerned, so he feels very strongly that they have to change the rules.
(They seem to be confusing Listeria with E.coli O157 in Romaine, but that’s Haaaaaaaaarvard.)
Brian Kenny: Which gets to another issue that the case raises, which is has the industry done well enough trying to regulate itself? What are some of the things the industry has tried to do?
Ray Goldberg: Under Danny Wegman’s leadership—he was the person in charge of food safety of the Food Marketing Institute that really looked at the whole industry—he got several members of the industry to sit down and create new rules with the FDA, the EPA, the USDA, and CDC, all of them saying we have to have better rules. Produce, as you know in the case, is the most valuable part of a supermarket but also the most susceptible to problems.
Brian Kenny: This gets a little bit to the topic of your book, Food System Advocates in an Era of Distrust. [What[ are the big ideas coming out of your book?
Ray Goldberg: The big ideas are two-fold, that the kind of men and women in the industry have changed from commodity handlers and bargaining as to how cheap they can buy something, or how expensive they can make something, to finally realizing that they have to be trusted. And because they have to be trusted, they have to start working together to create that trust. In addition to that, they realize that the private, public and not-for-profit sectors really need to work together. That’s why I tried to write a book to give people an inkling of the kind of men and women in this industry who really are the change-makers, who are changing it to a consumer-oriented, health-oriented, environmentally-oriented, economic development-oriented industry.
The educational methods enlisted to facilitate food safety certification included group meetings, instructional material delivery, individual farm instruction, and expert instruction. In addition, there were four challenges to food safety certification identified—the needs for motivation, information, clarification, and resources—along with strategies to address the challenges.
The program was found to be limitedly successful, producing ten GAP-certified operations. It was concluded that further evaluation of the educational methods is needed.
An educational program on produce food safety/good agricultural practices for small and limited resource farmers: a case study
December 2018
Journal of Agriculture and Life Sciences vol. 5 no. 2
A new report into Australia’s 2018 strawberry tampering crisis, which caused catastrophic economic damage to the industry, has found food-tracing protocols need to be strengthened.
Lucy Stone of The Sydney Morning Herald reports the report also found that food safety expertise in the horticulture industry was “variable” due to there being many small businesses, with no regulatory or industry oversight particularly for strawberry farmers (uh, I’m right here).
The “fragmented nature” of the sector also complicated matters with no regulation tracking strawberry farm locations during the crisis, and the use of seasonal or contract pickers muddying traceability.
Food Standards Australia New Zealand (FSANZ) was commissioned by Health Minister Greg Hunt to review the response to the strawberry contamination crisis, which began on September 9 when a man swallowed a needle hidden inside a strawberry.
Within days more reports had been made to Queensland Health and Queensland Police of similar incidents, sparking copycat actions of needles being hidden in fruit across Australia and New Zealand.
The crisis saw strawberry production nationally grind to a halt, with Queensland growers dumping thousands of tonnes of fruit that could not be sold.
Is there a better approach to both protect and enhance consumer confidence in the wake of an outbreak, tampering, or even allegations of such?
On June 12, 1996, Dr. Richard Schabas, chief medical officer of Ontario (that’s a province in Canada), issued a public health advisory on the presumed link between consumption of California strawberries and an outbreak of diarrheal illness among some 40 people in the Metro Toronto area. The announcement followed a similar statement from the Department of Health and Human Services in Houston, Texas, which was investigating a cluster of 18 cases of cyclospora illness among oil executives.
Turns out it was Guatemalan raspberries, not strawberries, and no one was happy.
The initial, and subsequent, links between cyclospora and strawberries or raspberries in 1996 was based on epidemiology, a statistical association between consumption of a particular food and the onset of disease.
The Toronto outbreak was first identified because some 35 guests attending a May 11, 1996 wedding reception developed the same severe, intestinal illness, seven to 10 days after the wedding, and subsequently tested positive for cyclospora. Based on interviews with those stricken, health authorities in Toronto and Texas concluded that California strawberries were the most likely source. However, attempts to remember exactly what one ate two weeks earlier is an extremely difficult task; and larger foods, like strawberries, are recalled more frequently than smaller foods, like raspberries.
By July 18, 1996, the U.S. Centers for Disease Control declared that raspberries from Guatemala — which had been sprayed with pesticides mixed with water that could have been contaminated with sewage containing cyclospora — were the likely source of the cyclospora outbreak, which ultimately sickened about 1,000 people across North America. Guatemalan health authorities and producers vigorously refuted the charges. The California Strawberry Commission estimated it lost $15-20 million in reduced strawberry sales.
The California strawberry growers decided the best way to minimize the effects of an outbreak – real or alleged – was to make sure all their growers knew some food safety basics and there was some verification mechanism. The next time someone said, “I got sick and it was your strawberries,” the growers could at least say, “We don’t think it was us, and here’s everything we do to produce the safest product we can.”
There is a lack – a disturbing lack – of on-farm food safety inspection; farmers need to be more aware of the potential for contamination from microbes (from listeria in rockmelon, for example) as well as sabotage.
There is an equally large lack of information to consumers where they buy their produce. What do Australian grocery shoppers know of the food safety regulations applied to the produce sold in their most popular stores? Do such regulations exist? Who can they ask to find the answers?
The Sydney Morning Herald also notes that in the report published on Friday, FSANZ made several recommendations to prevent similar crises in the future, including greater regulation for the industry.
The lack of a peak soft fruits regulatory body left the small Queensland Strawberry Growers Association “inundated with calls”, while national horticulture body Growcom later helping manage communication.
The crisis prompted Prime Minister Scott Morrison to announce legislation to extend the jail time for anyone convicted of food tampering to 15 years.
Food Standards Australia New Zealand made seven recommendations in its final report, including a recommendation that all jurisdictions review food incident response protocols.
A central agency should be engaged to manage national communication in future food tampering incidents, and communication between regulators, health departments and police should be reviewed, the organisation found.
Triggers for “activation and management of intentional contamination of food” under the National Food Incident Response Protocol (NFIRP) should also be reviewed.
This recommendation was despite the NFIRP not being activated during the strawberry contamination issue. The protocol is a national incident response that can be activated by any agency to manage food incidents.
“Due to the unique criminal nature of this case and associated investigation, the protocol was not triggered,” the report said.
The horticulture sector also needs a representative body to “support crisis preparedness and response”, and traceability measures to track food through the sector needed greater work.
“Government and industry should work together to map the current state of play and identify options and tools for enhancing traceability,” the FSANZ report recommended.
A single national website for food tampering should be set up to give the public clear information, the report found.
The report found greater regulation of the horticulture sector was needed and cited the complexity of small farm and distribution operations as making the investigation difficult.
A suggestion that strawberry farms should be fitted with metal detectors also raised concerns about cost and practicality, while tamper-proof packaging risked shortening shelf life, and criticisms about increased use of plastic packaging.
For 20 years, I have been advising fruit and vegetable growers there are risks: Own them: Say what you do, do what you say, and prove it. The best producers or manufacturers can do is diligently manage and mitigate risks and be able to prove such diligence in the court of public opinion; and they’ll do it before the next outbreak.
To acquire data on contamination with Norovirus in berry fruit and salad vegetables in the United Kingdom, 1,152 samples of fresh produce sold at retail in the UK were analysed for Norovirus.
Of 568 samples of lettuce, 30 (5.3%) were Norovirus-positive. Most (24/30) lettuce samples which tested positive for Norovirus were grown in the UK and 19 of those 24 samples contained NoV GI. Seven/310 (2.3%) samples of fresh raspberries were Norovirus-positive. Most (6/7) of the positively-testing fresh raspberry samples were imported, but no predominance of a genogroup, or any seasonality, was observed. Ten/274 (3.6%) samples of frozen raspberries were Norovirus-positive. The country of origin of the positively-testing frozen raspberry samples was not identified in most (7/10) instances.
The collected data add to the currently limited body of prevalence information on Norovirus in fresh produce, and indicate the need for implementation of effective food safety management of foodborne viruses.
Norovirus in produce sold at retail in the United Kingdom
Cook, N., Williams, L., & Dagostino, M. (2019). Prevalence of . Food Microbiology, 79, 85-89. doi:10.1016/j.fm.2018.12.003
One promising approach for targeting pathogenic bacteria in foods without impacting the normal food microbiota are bacteriophages. In this study, we observed that combinational treatment of conventional antimicrobials (PAA and chlorine) and bacteriophages, specifically the Salmonella‐targeted preparation SalmoFresh, retained the bactericidal effectiveness of individual interventions, and in some cases, achieved substantially increased efficacy. Additionally, the bacterial microbiomes of farm fresh and organic produce were less affected after phage treatment compared to PAA and chlorine.
