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 |
This is a test of the blog’s comment system
Duncan 1:39 pm on October 13, 2015 Permalink |
This is a test of the blog’s comment system, take 2.
wen liao 2:51 pm on October 16, 2015 Permalink |
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 |
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 |
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 |
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 |
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!