May 9, 2010, 6:17 AM
Post #1 of 31
Risks of Salmonella, Worms, Amoebas, & Protozoans
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I've noted a number past posts on how people got sick when visiting Mexico and even some articles on how some long-time residents "never" got sick while living here, which inspired to me to present a few findings we've collected over the years.
Montezuma's Revenge? . . . . . . . . . . . . Moctezuma's Revenge?
Reasons to take antibiotics or OTC semi-annual parasite treatments?
Here are a few observations from nationwide studies conducted by the US CDC, NIH, Mexican hospitals, and Mexican Medical Schools that suggest why both tourists and ex-pats NOB hygiene habits don't always work so well here in the Tropics, including ineffective Microdyne/Bacdyne/etc vegetable soaks and quick hand washes.
﻿Over 40% of Yucatecans have no bathroom / septic system facilities, 25% are basically illiterate, and across Mexico:
These study results showed that meat sold in typical Mexican grocery stores had equivalent or higher levels of salmonella contamination than was found in local animal intestine fecal samples. (Detailed analyses of the salmonella genotypes pointed to butchering practices as the most likely source of the contamination.)
These results for Mexico sure seem troubling, but are actually roughly 3X less contaminated than US commercial grocery store chicken: 83% of which nationally was found to be contaminated by either Salmonella or Campylobacter. (http://www.consumerreports.org/cro/magazine-archive/2010/january/food/chicken-safety/overview/chicken-safety-ov.htm)
If US chicken et al have similar or higher levels of commercial raw meat contamination, why would there be higher risks of getting food poisoning , worms, amoebas, or parasites in Mexico?
The CDC/Horan authors go on to say: "...in the other states (like Yucatan), Salmonella spp. infections are probably acquired by other modes of transmission aside from contaminated food, such as from person to person or by contact with animal feces. In settings with greater fecal-oral transmission, asymptomatic infections would not directly reflect contamination rates in the retail meat."
It is worth noting that these Salmonella were also resistant to most common antibiotics (except Cipro) in about 15% - 20% of the cases.
And then they put a nice bow onto this little present describing typical Yucatecan households:
Population >15 yr. old, who are illiterate or with incomplete primary education: 40.1%
Households with no toilet or latrine: 24.6%
Households with no sewage system: 40.8%
Percentage of kindergartners with endemic asymptomatic salmonella infections: 16%
(Sonora, Michoacan, & San Luis Potosi were only nominally better.)
Before we criticize too heavily, how many people with NOB habits wash their hands for 20 seconds of vigorously rubbing soapy suds on our hands? How many (likely illiterate) food service workers know what's needed to stop salmonella transmission?
How many expats and visitors from NOB know how to properly disinfect fruit and veg, counters, cutting boards, floors, etc?
Past NIH tests of fecal coliform contamination of commercial fruits and veg, in Mexico City consistently found high levels of salmonella in almost all samples, due to the use of "organic" (fecal) fertilizers and contaminated irrigation water = the wonders of Organic Farming. http://www.ncbi.nlm.nih.gov/pubmed/17061512
So, just what works, and what doesn't, if you want to keep yourself and your family safe and healthy?
A major NIH study evaluating Mexican vegetable contamination found that the silver colloid based disinfectants (like microdyne, biodyne, etc) lowered fecal coliform (pooh bacteria) counts, but did not eliminate them, and these same silver colloid products did not remove salmonella typhi risks in any samples. They found that bleach-based disinfectant solutions** were effective against all three major families of microbial contaminants tested (killing fecal coliforms, salmonella, and various pathogenic mesophillic microorganisms).
After having Walmart/Chederaui/Soriana/Mega-Commercial meat sometimes go bad in as little as 2 days, I started watching meat handling practices at these stores, checking out different stores to try to find a good one, and I found that employees routinely pack and un-pack the cases, leaving the meat sit out, warm, in carts 1 - 2 hr at all of these stores.
I really hate food poisoning, since I've been more susceptible after a number of really wicked bouts in Ukraine after the break-up of the Soviet Union, so, I began feeling the packages in the cold cases of each store, and often find the meat warm - room temp - to the touch. The meat department in every single store mentioned (here in Merida) has smelled absolutely awful at least once in the past 3 years, much worse than anything I'd experienced in 40 years of shopping in the States. We've had similar issues with the Deli sections of the aforementioned stores, with occasional ham and bacon going bad within 24 hrs of purchase (due to the meat sitting out warm during some earlier point). The only reliable solution we've found is to buy meat that is still frozen, as it is sold at Super Aki, and to prepare and cook things carefully. Some people rely on fresh-killed meats from local butchers, but all it takes is one fly to land on that, blow a few of their regurgitated bubbles, and even that meat has surface contamination.
Fortunately, typical bacterial contamination is only on the outside of meat (though not true for hamburger and ground meats where the grinding process distributes the contamination throughout the meat). This means that well cooked meat (thoroughly maintained at temperatures above 145ºF for at least 3 minutes) is safe from bacterial, protozoan, and amoebic contamination. One might also note that the lime juice used to prepare ceviche does not kill worms nor their encysted forms, potentially important as past studies have found roughly 80% of ocean fish have some sort of parasites.
Walk barefoot on the beach, enjoy the surf, eat some ceviche or local sashimi/sushi, & as a bonus: take home some extra "special souvenirs". (Souvenirs that your local NOB physician likely has no idea of how to diagnose or treat.)
The remaining kitchen/prep problems are solved by immediate careful disinfection** of cutting & handling tools, disinfection of cutting boards, & anything touched by the raw meat, (disinfect using dilute bleach**), followed by thorough hand washing (20 seconds of soapy suds using an antibacterial soap).
http://www.cdc.gov/...content/14/3/429.htm from Emerging Infectious Diseases
It's also worth noting that the high %'s of salmonella on retail meat should also translate to salmonella on the outside of the meat packages. To avoid contaminating your hands, then touching the handle of the shopping cart, and your car's steering wheel, if you shop for your fruit and veg first, you have a chance to pick up some extra plastic bags. If you slip the bag over your hand, pick out your meat, and then invert the bag over your meat package, you can keep your hands, the shopping cart handle, and your car door handles and steering wheel reasonably clean.
It also helps the clerk if you insert the meat package with the $$$ sticker close to the open end of the baggie, so, they can easily flip back the baggie to scan the sticker. Don't get me started thinking about other shoppers handling the meat, and then touching the cart handles, which we then touch, and then we go out to our cars and handle the steering wheel...
Post Script to keep things in perspective:
US Turkey was no better in past USDA studies: roughly 50% of US retail turkey had salmonella.
US Chicken has been worse: 65% - 83% of retail chicken tested had salmonella and or campylobacter.
US Beef and Pork were far cleaner @ under 5% with salmonella.
Walking barefoot (on the beach?) clearly exposes people to hookworms both in Mexico & the US.
Since the early 1970's roughly 15% of all people in the US South (from Texas to Florida) have asymptomatic intestinal worms, and estimates run as high as 70% for Mexicans who do not get semi-annual treatments for worms and parasites.
All of this means that illiterate food service workers very likely transmit low levels of microbes and parasites to unsuspecting diners, and that if you rely on Microdyne, Bacdyne, etc, they just don't work. (and no, even though their names imply having iodine as an ingredient: they actually use colloidal silver). Short hand washes also don't work, but learning to not touch your mouth, nose, and eyes does help.
A few final thoughts:
Soap and hot water do not disinfect things nor do they kill microbes. Soap and water simply remove dirt, grease, and biofilms that offer places for microbes to grow.
To kill microbes (disinfect things) & eliminate the hazards described above it takes either:
- harsh chemicals (like dishwasher soap) and high temperatures (3 minutes @ 145ºF or 65ºC) or chemical disinfectants (like dilute bleach solutions**) or
- crown ethers (like in bar-glass washing solutions),
- triclosan, as in antibacterial soaps, or
- peroxide, or
- alcohols like the hand disinfectants popular since H1N1 flu outbreaks.
**Bleach Dilution Schemes:
- Stored Water Treatment (tinacos etc): 10 mL (1 tsp) bleach per 100 L of non-turbid clear water or 1/4 cup of bleach per 275 gal tinaco makes water microbially safe in 15 minutes.
- Toilets and Sinks: Apply bleach without dilution via spray or brush for 10 minutes and rinse.
- Drinking water: 2 drops of bleach per liter of clear water (20 drops per mL) and wait 15 min.
- Fruits and Vegetables: Wash & scrub thoroughly first to remove dirt, then 10 drops bleach per liter of water and soak for 5 minutes. Rinse thoroughly.
- Floors and bathroom surfaces (tub & shower): 1/4 cup (60 mL) bleach per gal of wash water and leave it on the surface for 5 minutes before rinsing.
- Children's Plastic Toys: Remove dirt first with soap and water, then use 1/4 cup (60 mL) bleach per liter of water and soak for 5 minutes and rinse.
- Baby Bottles & Nipples: 1 drop of bleach per liter, soak for 2 minutes and rinse.
- Other Plastic Objects: Apply straight bleach for 5 minutes and rinse - note that this might cause a permanent bleaching of some plastics.
- Glasses and Plates: 1/4 cup (60 mL) per gallon of dish washing soapy water, scrub off food residues, and allow to soak for 5 minutes.
- Only use unscented normal bleach for these purposes: do not use scented nor non-splash bleach.
(Blanqueador de Ropa)
- NEVER COMBINE BLEACH WITH ANY BASE (higher pH chemical)
- NEVER MIX BLEACH SOLUTIONS WITH AMMONIA PRODUCTS OR DRIED URINE (concentrated UREA),
because Base + Bleach = Toxic Chlorine Gas.
Some people report that regular dosing with freeze dried probiotic mixtures of beneficial bacteria and fungi can overseed our GI systems with microbes that put out the "No Vacancy" sign to incoming pathogens.
There is no joy in Mudville...
(We take no glee in describing these risks.)
But with knowledge, you can improve your chances.
*If you liked this kind of post/article, check out our blog.
E-visit at http://yucalandia.com
(This post was edited by YucaLandia on May 9, 2010, 8:03 AM)