Discard produce tainted by flood waters

West Virginia agricultural officials are advising growers to discard vegetables that have had contact with flood waters.

flood.midwestThe advice comes after weeks of rain that promoted Gov. Earl Ray Tomblin to declare states of emergency in 10 counties this week.

West Virginia extension agent John Bombardiere says the safest way to deal with lettuce, tomatoes or potatoes that have been tainted by flood water is to toss them. He says they should not be consumed by humans or animals.

The advice is based U.S. Food and Drug Administration guidelines, which state there is no practical way to salvage the product.

Iron Cross Blister beetles in imported pre-packaged leafy vegetables in Canada

Never heard of a blister beetle, but they look sorta cool.

cfia.blister.beetleThe Canadian Food Inspection Agency (CFIA) is conducting an investigation into the presence of Iron Cross Blister beetles (Tegrodera spp.) in imported leafy vegetables following recent consumer complaints of these beetles in pre-packaged salads. There have been no confirmed illnesses or injuries associated with the consumption of these products.

Fresh produce can harbor insects that may be injurious to consumers, but this is rare. The Iron Cross Blister beetle is very distinctively colored, with a bright red head and bright yellow markings on the wings, separated by a black “cross”. This particular beetle should be treated with caution as it may release an irritating chemical called “cantharidin.” This chemical may cause blisters at the point of contact.

Consumers are advised to wash and visually inspect their leafy vegetables thoroughly. The beetle should be removed without touching or crushing it. If found, please advise your local CFIA office.

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

Nanotech to make produce safer?

Nearly half of foodborne illnesses in the U.S. from 1998 through 2008 have been attributed to contaminated fresh produce. Prevention and control of bacterial contamination on fresh produce is critical to ensure food safety. The current strategy remains industrial washing of the product in water containing chlorine.

(an effective on-farm food safety program helps)

lettuceHowever, due to sanitizer ineffectiveness there is an urgent need to identify alternative antimicrobials, particularly those of natural origin, for the produce industry.

A team of researchers at Wayne State University have been exploring natural, safe and alternative antimicrobials to reduce bacterial contamination. Plant essential oils such as those from thyme, oregano and clove are known to have a strong antimicrobial effect, but currently their use in food protection is limited due to their low solubility in water. The team, led by Yifan Zhang, Ph.D., assistant professor of nutrition and food science in the College of Liberal Arts and Sciences, explored ways to formulate oil nanoemulsions to increase the solubility and stability of essential oils, and consequently, enhance their antimicrobial activity.

“Much of the research on the antimicrobial efficacy of essential oils has been conducted using products made by mixing immiscible oils in water or phosphate buffered saline,” said Zhang. “However, because of the hydrophobic nature of essential oils, organic compounds from produce may interfere with reducing the sanitizing effect or duration of the effectiveness of these essential oils. Our team set out to find a new approach to inhibit these bacteria with the use of oregano oil, one of the most effective plant essential oils with antimicrobial effect.”

Zhang, and then-Ph.D. student, Kanika Bhargava, currently assistant professor of human environmental sciences at the University of Central Oklahoma, approached Sandro da Rocha, Ph.D., associate professor of chemical engineering and materials science in the College of Engineering at Wayne State, to explore options.

“In our research, we discovered that oregano oil was able to inhibit common foodborne bacteria, such as E. coli O157, Salmonella and Listeria, in artificially contaminated fresh lettuce” said Zhang. “We wanted to explore the possibility of a nanodelivery system for the oil, which is an area of expertise of Dr. da Rocha.”

The team initially considered the use of solid polymeric nanoparticles for the delivery of the oil, but da Rocha suggested the use of nanoemulsions.

“My team felt the use of nanoemulsions would improve the rate of release compared to other nanoformulations, and the ability of the food grade surfactant to wet the surface of the produce,” said da Rocha. “We were able to reduce L. monocytogenes, S. Typhimurium, and E. coli O157 on fresh lettuce. Former Ph.D. student Denise S. Conti, now at the Generics Division of the FDA, helped design the nanocarriers and characterize them.”

The team added that while there is still work to be done, their study suggests promise for the use of essential oil nanoemulsions as a natural alternative to chemicals for safety controls in produce.

“Our future research aims to investigate the antimicrobial effects of essential oil nanoemulsions in various combinations, as well as formulate the best proportions of each ingredient at the lowest possible necessary levels needed for food application, which ultimately will aid in maintaining the taste of the produce.”

More information: The study, “Application of an oregano oil nanoemulsion to the control of foodborne bacteria on fresh lettuce” appears in the May 2015 issue of Food Microbiology. www.sciencedirect.com/science/article/pii/S0740002014002676

It’s there: Salmonella in irrigation water

Here’s a video featuring farmer Jeff from 2003, before youtube existed.

And an abstract from a paper just published.

farmer.jeff.water.2003Same questions, not many solutions.

Irrigation water has been implicated as a likely source of produce contamination by Salmonella enterica. Therefore, the distribution of S. enterica was surveyed monthly in irrigation ponds (n=10) located within a prime agricultural region in Southern Georgia and Northern Florida.

All ponds and 28.2% of all samples (n=635) were positive for Salmonella with an overall geometric mean concentration (0.26 MPN/L) that was relatively low compared to prior reports for rivers in this region. Salmonella peaks were seasonal; levels correlated with increased temperature and rainfall (p<0.05). Numbers and occurrence were significantly higher in water (0.32 MPN/L and 37%) compared to sediment (0.22 MPN/L and 17%) but did not vary with depth. Representative isolates (n=185) from different ponds, sample types, and seasons were examined for resistance to 15 different antibiotics; most strains were resistant to streptomycin (98.9%), while 20% were multidrug resistant (MDR) for 2-6 antibiotics.

DiversiLab rep-PCR revealed genetic diversity and showed 43 genotypes among 191 isolates, as defined by >95% similarity. Genotypes did not partition by pond, season, or sample type. Genetic similarity to known serotypes indicated Hadar, Montevideo, and Newport as the most prevalent. All ponds achieved the current safety standards for generic Escherichia coli in agricultural water, and regression modeling showed E. coli levels were a significant predictor for the probability of Salmonella occurrence. However, persistent populations of Salmonella were widely distributed in irrigation ponds, and associated risks for produce contamination and subsequent human exposure are unknown, supporting continued surveillance of this pathogen in agricultural settings.

Distribution and Characterization of Salmonella enterica Isolates from Irrigation Ponds in the Southeastern U.S.A.

Applied and Environmnetal Microbiology

Zhiyao Luo, Ganyu Gu, Amber Ginn, Mihai C. Giurcanu, Paige Adams, George Vellidis, Ariena H. C. van Bruggen, Michelle D. Danyluk, and Anita C. Wright

http://aem.asm.org/content/early/2015/04/20/AEM.04086-14.abstract

12 sick: E. coli leafy greens cone of silence, again

The Public Health Agency of Canada is collaborating with federal and provincial public health partners to investigate an outbreak of Escherichia coli O157:H7, commonly called E.coli, with a possible link to leafy greens. A specific product has not been identified yet, and the investigation is ongoing.

lettuce.skull.e.coli.O145At this time, the risk to Canadians is low. However, Canadians are reminded to follow safe food handling practices to avoid illness. (WTF are Canadians supposed to do with leafy greens?)

There have been 12 cases of E. coli with a matching genetic fingerprint reported in Alberta (9), Saskatchewan (1), Ontario (1), and Newfoundland and Labrador (1). The illness onset dates range from March 13 to March 31, 2015.

Based on the investigation findings to date, exposure to leafy greens has emerged as a possible source of illness. Leafy greens can include all varieties of lettuces and other green leaf vegetables such as kale, spinach, arugula, or chard. The Canadian Food Inspection Agency’s investigation into the food source is ongoing. If products are identified, the Agency will inform the public and ensure that they are promptly removed from the marketplace.

The following tips will help you reduce your risk of infection with E. coli or other food-borne illnesses:

Wash fresh fruits and vegetables before eating them, clean counters and cutting boards and wash your hands regularly.

Bullshit. Packaged leafy greens are not to be re-washed.

Australian taxpayers and growers are led up a garden path

(I and others applied for this, but knew it was an inside job. Here is the take from Australian Food News)

lettuce.skull.e.coli.O145The Fresh Produce Safety Centre (FPSC), which is an organisation established with government and industry support in 2013, has announced the winning tender bid for the conduct of a literature review of fresh produce safety research.

The announcement has produced some skepticism from commentators about the whole bureaucratic process involving the Fresh Produce Safety Centre’s role in improving the current Australian food safety regime for fresh produce.

The principal industry sector group supporting the establishment of the Fresh Produce Safety Centre has been the Produce Marketers Association Australia New Zealand (PMA A-NZ), which is the representative body of importers and international traders of fruit and vegetables.

The major supermarkets and food safety audit organisations already follow and monitor their own very strict food safety protocols at all points in the supply chain. Commentators are therefore asking why it ought be necessary for the FPSC to be ‘reinventing the wheel’.

Incidentally, the winning tender bid is a team consisting of TQA Australia Inc, RMCG, and the Institute of Environmental Science and Research in New Zealand, in concert with the Food Safety Centre at the University of Tasmania. The project has the support of the NSW Food Authority, Pip Fruit New Zealand, Golden State Foods and Snap Fresh Foods, and Fresh Select.

In 2009-2010, a process had been initiated by Food Standards Australia New Zealand (FSANZ) to incorporate food safety primary production and processing standards for horticultural produce into the Australia New Zealand Food Standards Code (Food Standards Code). However, the PMA and some of the major produce importers opposed the inclusion in the Food Standards Code of a set of food safety standards for their industry sector. Ultimately, the Federal Government relented and the FSANZ process for developing a new mandatory food safety standard was aborted.

The reasons given at the time for the abandonment of the proposals included: the fact that the majority of horticulture product grown in Australia is already grown under a food safety scheme, and that a better understanding of those products that were not grown under a food safety scheme was required before further regulation should be considered.

FSANZ proposed a collaboration between the horticulture industry and government – with suggested measures such as “targeted guidance, codes of practice, education materials and training” and better through-chain traceability measures.

The PMA took the initiative to establish the concept of a ‘fresh produce safety centre’ with government and industry backing.

Some commentators are now consider the whole process a ‘waste of time and industry resources, and taxpayer funds’, especially for growers, supermarkets and other operators in the horticultural supply chain within Australia.

Probably cilantro that sickened hundreds with cylospora in 2013; better detection needed

The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas.

cilantroWe defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted.

Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0–∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico.

Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.

2013 multistate outbreaks of Cyclospora cayetanensis infections associated with fresh produce: focus on the Texas investigations

Epidemiology and Infection [ahead of print]

Abanyie, R. R. Harvey, J. R. Harris, R. E. Weigand, L. Gual, M., Desvignes-Kendrick, K. Irvin, I Williams, R. L. Hall, B. Herwaldt, E. E. Gray, Y. Qvarnstrom, M. E. Wise, V. Cantu, P. T. Cantey, S. Bosch, A. J. Da Silva, A. Fields, H. Bishop, A. Wellman, J. Beal, N. Wilson, A. E. Fiore, R. Tauxe, S. Lance, L. Slutsker and M. Parise

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9644741&fileId=S0950268815000370

Listeriosis and Produce: What’s the Connection? (via The Abstract)

I’m collaborating with Matt Shipman, public information officer at NC State University and curator of The Abstract, on a set of food safety-related posts from other NCSU folks as we roll toward WHO’s World Health Day on April 7– which is focused this year on food safety. Here’s a post on Listeria’s history with produce by Danisha Garner, a graduate student in NC State’s Department of Food, Bioprocessing and Nutrition Sciences.

In the United States and other industrialized nations, consumption of fresh fruits and vegetables is considered a key component of a healthy diet.

There are many benefits to eating fresh produce such as receiving adequate vitamins and minerals, reducing the risk of heart disease, lowering blood pressure, and preventing some types of cancer. Even healthy foods, however, can be vehicles for foodborne pathogens. Indeed, fresh produce is now considered a major contributor to human foodborne disease, and an increasing number of produce-associated foodborne disease outbreaks have occurred in recent years.

An especially worrisome trend is the increase in outbreaks of listeriosis, involving the pathogen Listeria monocytogenes.

Danisha Garner. Photo courtesy of Danisha Garner.

What Is Listeriosis?

Although it is relatively uncommon, human listeriosis remains a major public health concern due to high hospitalization and death rates. In fact, it has the highest hospitalization rate of all foodborne pathogens in the U.S. and is the third largest contributor to deaths from foodborne illness. Symptoms of infection can be severe and include septicemiameningitis, stillbirths and abortions. At high risk are the elderly, pregnant women and their fetuses, and patients with cancer and other immunocompromising conditions.

L. monocytogenes can be found in decaying plant material, soil and water, and has been detected on many types of fresh produce. Its reservoirs in nature remain poorly characterized but likely include soil and vegetation. Major contributors to the ability of L. monocytogenes to contaminate foods include its capacity to persistently colonize the environment and equipment of both food processing plants and produce packing sheds, and to grow even at refrigeration temperatures. Hence, foods typically implicated in human listeriosis are those that are processed, cold-stored and ready-to-eat – i.e. consumed without further treatment.

History of Listeriosis Outbreaks

The first outbreak of human listeriosis to be epidemiologically investigated (and to confirm foodborne transmission of the pathogen) involved produce (coleslaw) and took place in the Maritime Provinces of Canada in 1981. However, most subsequent outbreaks involved dairy products (especially soft cheeses) and ready-to-eat meats. Fresh produce was generally considered at low risk for listeriosis.

This situation changed dramatically in 2011, when one of the largest listeriosis outbreaks on record was traced to contaminated whole cantaloupe and resulted in a total of 147 cases of illness and 33 deaths across 28 states. This was also the first time that whole cantaloupe was found to serve as food vehicle for listeriosis. Contamination of the cantaloupes occurred in the packing facility, likely due to inadequate cleaning and sanitation of equipment. The pathogen was not recovered from the field where the melons were grown or from fruit prior to packing.

Even though additional melon-associated outbreaks of listeriosis have not been noted since the 2011 outbreak, several other produce-associated outbreaks have been documented in the U.S. since 2010. Implicated produce included diced celery (2010), sprouts (2014) and commercially produced, prepackaged caramel apples (2014). In all investigated cases, the source of contamination was the packing/processing environment or equipment. These outbreaks highlight the importance of having good sanitation practices in the packing/processing facility to prevent or reduce contamination with Listeria and other pathogens.

Research and Prevention

At NC State, several efforts are being focused on characterizing Listeria-produce associations with the ultimate goal of identifying new tools and strategies to reduce the risk of contamination.

In the Department of Food, Bioprocessing and Nutrition Science, researchers in the lab of Sophia Kathariou are collaborating with Lisa Gorski and William G. Miller at USDA-ARS to investigate genes of L. monocytogenes that mediate the pathogen’s adherence and growth on both fresh produce and on surfaces likely to be encountered in packing sheds and processing plants.

In collaboration with Christian Melander (in NC State’s Department of Chemistry) the Kathariou lab is also investigating the potential of novel compounds to prevent or disperse biofilms formed by L. monocytogenes on environmental surfaces and equipment. Such research will be critically needed for development of novel tools and strategies to ensure the safety of fresh produce and reduce the risk for human listeriosis.

More information about Listeria monocytogenes and listeriosis outbreaks can be found at http://www.cdc.gov/listeria/

Safety don’t have much to do with it: Food safety audits are just what retailers wanted

I’m not Dr. Doug.

doug.coach.happy.feb.15Kids call me coach, others call me asshole, all fine by me.

Dr. Bob and Dr. Dan exist, and probably many others in the misguided belief they are enhancing the public understanding of science, when it’s just demeaning and arrogant.

Dr. Bob says during grower food safety events, “we often talk about why having a food safety program is important and how it is critical to have a program to protect your own business, protect your customers and, ultimately, public health. We talk about emerging science, the importance of foundational food safety programs such as sanitation practices and worker hygiene and how to identify and manage potential cross-contamination hazards on the farm and in the packinghouse.

“After going through this information and basically laying out the why, how, and what of food safety, often some brave soul in the audience will raise their hand and ask, So what score do I need to get in order to pass the audit? And that’s when the frustration sets in. How did passing an audit become a substitute for actually building a risk-based food safety program?”

Oh, Oh, Dr. Bob, I can answer that.

Because back in the late 1990s, as fresh fruit and vegetable outbreaks took on national prominence, retailers decided, we want third-party audits, rather than food safety programs promoted by grower groups.

I chaired a national committee in Canada about 2002 to look at the issue, came up with a solution that would be advantageous to growers and consumers, and was then overruled behind the scenes so the grower groups could keep their Canadian Food Inspection Agency funding (and the bureaucracy).

I walked away.

Thirteen years later and Dr. Bob is wondering how this happened?