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  • ayra casuga 1:18 pm on November 27, 2015 Permalink | Reply
    Tags: , coriander, , shigella, Sweden, vegetable   

    Southeast Asian Imported Coriander had caused 40 cases of Shigellosis in Sweden 


    In late October 2015, Southeast Asian imported coriander has caused an outbreak of Shigellosis in Sweden. The severity of this outbreak had caused forty reported illnesses in three areas (twenty-nine from Vastra Gotaland, ten from Skane, and three from Halland). There was the same proportion of adult male and female who had fallen ill and no reported deaths.

    Shigellosis is an acute bacterial infection caused by a group of Shigella bacteria. It is linked with “poor sanitation, contaminated food and water, and crowded living conditions”(Vyas, et al., 2014). Some symptoms include acute abdominal cramping, fever, bloody stools, watery diarrhea, and nausea (Vyas, et al., 2014). The severity of Shigellosis is mild as healthy individuals are able to surpass this illness with no chronic issues. However, the severity increases for malnourished children and immune-compromised individuals.

    Coriander is a type of herb commonly used to complement a variety of foods and recipes as it adds a spicy flavor component that many find appealing. Therefore, it is commonly found in restaurant dishes where, in this case, has been the likely source of the illnesses reported in Vastra Gotaland and Skane. The Public Health Agency of Sweden had interviewed the people who were sick as part of their outbreak investigation and had found that there was a connection between different restaurants.

    In addition to interviewing those who were sick, the Public Health agency of Sweden used “Whole-Genome Sequencing of the Shigella bacteria from the people who fell ill after visiting different restaurants” (Whitworth, 2015). Whole-genome sequencing is a type of molecular subtyping method used to reveal the complete genome of an organism in order to identify pathogens isolated from food samples (FDA, 2015). First, a sample is taken from a patient and is then cultivated in order to isolate bacterial DNA. After, the bacterial DNA found in the specimen becomes processed using an automated bench-top sequencing system. In other words, the bacterial DNA becomes processed in order to determine the order of nucleotides within its genome. Finally, this information can then be analyzed and compared to central data storage of known DNA bacterial sequences, in this case is the Shigella bacteria (Wang, Lecture Slide 18, 2015).

    As a result from implementing a whole genome sequencing method, the Public Health Agency of Sweden did not detect the Shigella bacteria in any samples that were taken. Although the samples taken of the people ill showed close to identical bacterial strains, which suggests that their illness had most likely came from a common source. In addition, the coriander could not have been analyzed as it had disappeared from the marketplace before the outbreak became known. However, upon interviewing the people who were ill, it has been determined that coriander had been a common denominator found in the restaurant meals. This analysis has leaded the Public Health Agency of Sweden to conclude that the source of illness is the imported coriander from Southeast Asia.

    This outbreak is a great example of the level of difficulty it is to find the cause of an outbreak when the cause is most likely an ingredient in a meal. Because the whole-genome sequencing indicate negative results for the presence of Shigellosis raises a lot of questions for the conclusions made by the Public Health Agency of Sweden. However, through their findings it is highly likely that the cause of the outbreak is from the coriander, but it is yet to be determined whether the illness is, indeed, Shigellosis. In order to ensure that similar outbreaks like this do not occur again, more stringent policies can be implemented to ensure that imported produce has come from the cleanest foreign companies.

    Discussion Question: From what we have learned in class about the outbreak investigation method in Canada, would you agree with the Public Health Agency of Sweden to conclude that the source of illness had come from the Coriander? If not, what methods could they have further done to accurately determine the source of the Shigellosis bacteria?

    References –
    Witworth, J. (2015, November 25). Shigella outbreak traced to imported coriander. Retrieved November 26, 2015, from http://www.foodqualitynews.com/Food-Outbreaks/Sweden-finds-coriander-to-be-source-of-shigellosis

    Wang, S. (2015). Lecture Slide 18: Molecular Subtyping. FNH 413 Food Safety

    Vyas, M. (2014, May 12). Shigellosis. Medline Plus. Retrieved November 26, 2015, from https://www.nlm.nih.gov/medlineplus/ency/article/000295.htm

    FDA (2015, March 5). Whole Genome Sequencing (WGS) Program. U.S. Food & Drug Administration. Retrieved November 26, 2015, from http://www.fda.gov/Food/FoodScienceResearch/WholeGenomeSequencingProgramWGS/

    • Michelle Ebtia 12:16 pm on November 29, 2015 Permalink | Reply

      The conclusion made by the Public Health Agency of Sweden seems to me to be based on guesswork rather than hard data. The article reports that analysis of the coriander samples showed no positive results for the pathogen, however the outbreak was still attributed to that same batch of produce! This reminds me of the case with Spanish cucumber and fenugreek seeds from Egypt that was discussed in class.
      I think more investigation is needed to attribute the illness to one specific food, based on scientific findings. If no evidence emerges, then the case could be reported as unresolved, similar to numerous outbreaks in Canada.
      It is also very interesting to know that despite using the most comprehensive and advanced method available (Whole Genome Sequencing), these complications may arise in practice!

    • csontani 9:45 am on November 30, 2015 Permalink | Reply

      That would be so hard for the company who exported to products cause they might be exporting products to many other countries and might forced them to recall the products and the outbreak might not even be because of their products. But the Public Health Agency of Sweden should have make another hypotheses because their data results did not supported their original hypotheses and shouldn’t conclude their investigation based on guesses. That would not be fair for the company who exported the coriander.

    • NorrisHuang 4:14 pm on December 1, 2015 Permalink | Reply

      I wonder why the Public Health Agency of Sweden used whole genome sequencing as their first and only investigation method though, because WGS is the most expensive one. Since WGS is the one with highest discriminatory power, I think instead of using new methods, the agency can test for more samples and see if they were able to find positive samples. If not, then probably coriander is not the real cause of food-borne illnesses?

    • angel519 5:28 pm on December 1, 2015 Permalink | Reply

      I like how your blog links to the process outbreak investigation that we’ve learnt in class. I personally think that the Public Health Agency of Sweden should not conclude that the coriander originated from South East Asia is the source of the outbreak. This is because no samples of the coriander were tests, which means they have no evidence to suggest that the coriander contains the strains of Shigella that matches with the infected patients. However, as mentioned in the blog, the suspect coriander can no longer be found in the market. From this I’ve learnt that it is a struggle that a real outbreak investigation could encounter.

    • MarinaMoon 1:53 pm on December 4, 2015 Permalink | Reply

      I agree with above comment that the Public Health Agency of Sweden should not have concluded the outbreak of coriander to be originated from South East Asia. Although it is a very likely source of the outbreak, without enough data to evidently state the outbreak cause, it should not have confirmed its case. If it wasn’t from the coriander from South East Asia, it will put the farmers into extra steps and cost that were not necessary if the investigation included further research. Also, this would put the farmers of South East Asia with bad reputation which they are not responsible for. From the article, I realized how it is very hard to trace back food sources for contamination and that preventing it from happening in the first place is the best strategy.

  • NorrisHuang 11:08 pm on October 12, 2015 Permalink | Reply
    Tags: Alberta, , , contamination, , , , , Vancouver, vegetable   

    Escherichia coli on fresh produce 

    Escherichia coli (E. coli) are gram-negative, rod-shaped bacteria that cause a great number of food-borne illnesses annually. For example, according to PHAC, there were 470 reported cases of E. coli O157:H7 infections in Canada in 2013, which was the third highest among all pathogenic bacteria. Although E. coli infection is often referred to as “hamburger disease”, these bacteria also contaminates fresh produce. Earlier this year (between March 13 and 31), there were several E. coli infections cases identified in Canada, majority (9 out of 12 cases) of which were reported in Alberta. More investigations by CFIA are underway, however, leafy greens are considered to be the most possible cause of infections. Depending on strains, consequences of E. coli infections vary. Most people suffer from stomach discomfort, diarrhea and vomiting. Those who are infected with pathogenic strains such as O157:H7 may develop more severe symptoms, such as kidney failure.

    In addition to bacterial contamination, a research done by a group of UBC researchers shows a concerning fact that 97% of E. coli isolated from leafy greens samples purchased from several farmers market in Vancouver were antibiotic-resistant. To be more specific, antimicrobial resistance of E. coli on fresh green, red, and romaine lettuce samples were evaluated. 58% of samples were resistant to amikacin, 48% were resistant to trimethoprim and 45% were trimethoprim-sufamethoxazole-resistant. Resistance to nalidixic acid, kanamycin, ampicillin, amoxicillin-clavulanic acid, cefoxitin, gentamicin and tetracycline were also found. Luckily, only 13% of samples were found to be contaminated with trace amount of E. coli and the microbiological quality of produce was acceptable according to Health Canada guidelines.

    You can read more about the 12 E. coli cases in Canada here: http://globalnews.ca/news/1942601/health-officials-suspect-e-coli-illnesses-linked-to-leafy-greens/

    The use of antimicrobial agent on food animal (e.g. chicken) is one possible cause of antibiotic-resistance in E. coli on fresh produce. Antimicrobial agent is used to promote growth of food animal. Nonetheless, only 10% of the drug would be absorbed by animals and the rest will be excreted. As the wastes are applied as fertilizers. Antibiotics are also introduced to the environment (e.g. soil, water) and vegetables. Antibiotics selects for drug-resistant bacteria on leafy produce, which leads to predominant of antibiotic-resistant bacteria. Additionally, contaminated irrigation water, poor personal hygiene and inadequate food processing also adversely affect microbiological safety of greens.

    To protect ourselves from E. coli contaminations on vegetables, the following precautions can be taken:

    • Wash produce thoroughly before consumption
    • Clean and sanitize food-contact surfaces properly, including cutting boards, knifes, etc.
    • Wash hands for at least 20 seconds with warm water and soap regularly during food handling
    • Keep raw meat and vegetables separated to avoid cross-contamination
    • Store food at refrigerating temperature (< 4 ͦC) to inhibit bacterial growth

    For more information about E. coli, see: http://www.phac-aspc.gc.ca/fs-sa/fs-fi/ecoli-eng.php

    • Duncan 1:37 pm on October 13, 2015 Permalink | Reply

      This is a test of the blog’s comment system

    • Duncan 1:39 pm on October 13, 2015 Permalink | Reply

      This is a test of the blog’s comment system, take 2.

    • wen liao 2:51 pm on October 16, 2015 Permalink | Reply

      Haha this is like a very classical example about the effect of antimicrobial misuse as we have talked in class. I have also read similar articles talking about how the bacteria isolated from vegetables are resistant to one or multiple antimicrobials, which sounds quite scary to me, to be honest. However, although the issue with antimicrobial misuse has been prevalent for years and scientists have been addressing this problem at different scenarios, not very many people have taken it seriously. I have a friend who recently got flu, and his doctor prescribed him with antibiotics LOL….In addition although the stuff turkey season is almost gone, I till recall this news I read about how you should not wash store packaged turkey before you baked it in the oven. While wash the turkey with running water cannot remove the bacteria on the surface of the turkey skin, this action might spread the cells all over on the turkey causing more contamination. I don’t know if it would be the same case for your e. coli suggestions haha.

    • dgozali 9:07 pm on October 18, 2015 Permalink | Reply

      I think your article brought up a very important issue of growing antimicrobial resistance. Its quite alarming that a large proportion of E. coli found on leafy greens are resistant as most people consume these vegetables raw and some might not even bother washing them as they’re often labelled as a “ready to eat” food. Hence this makes it much easier for people to get sick from consuming these products. This reminds me of the recent outbreak at UBC’s centenniel celebration where many people got sick from eating the produce from the UBC farm. Perhaps the microbes were resistant strains as well. Either way, this is an increasingly prominent issue that should be taken more seriously!

    • CindyDai 10:42 am on October 23, 2015 Permalink | Reply

      The increasing antimicrobial resistance of E. coli indicates the increasing difficulty of controlling E. coli in food industry. To protect our families, handling food safely is crucial to eliminate any E. coli survived the factory processing in leafy greens. In the original news, there are a few more useful tips from PHAC on safe food handling. I learned that we should always reheat leftovers until steaming hot before eating. Especially for leafy greens, we should always keep them refrigerated and only take them out of fridge right before consumption. When there are E. coli outbreaks, cooking vegetables is a better choice. Food safety is in our hands!

    • ya gao 9:00 pm on October 23, 2015 Permalink | Reply

      After reading this post, I think it is important for government agencies like CFIA to realize the presence of antimicrobial resistant strains of E. coli on leafy green products. Although only 13% of samples were found to be contaminated with trace amount of E. coli and the microbiological quality of produce was acceptable according to Health Canada guidelines, it is a serious problem once breaks out. Leafy green products are usually considered as ready to eat foods and people consume them without heat processing step. With the increasing problem of antimicrobial resistant strains of E. coli on ready to eat foods, food safety may be threaten. CFIA should find a way to resolve this problem by controlling the use of fertilizer from animal waste, as well as doing sample testing on leafy green products more frequently.

    • AngeliMalimban 6:11 pm on December 12, 2015 Permalink | Reply

      I think it is interesting how people have a common misconception about how E. coli can only be found in raw beef. I remember my friend freaking out about my other friend preparing raw beef burgers, while she ate the salad that was from fresh produce. Could she have washed it well enough? Even then, it probably would still contain E. coli since it does not come out unless it is cooked.
      Salads are such a big fad in our society due to its nutritional value, but people should not be surprised if they get sick eating this. It’s also hard to cook vegetables because its nutritional value is best when raw, as most of the vitamins and minerals could dissolve in the water (if boiled) and let’s be real… it’s just SO much easier to eat vegetables raw so we do not have to go through the labour of cooking it!

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