eNutrition
a LaFrance Consulting Services™ e-Course
Nutrition for Nursing Students, independent study

Foodborne Illness

Picture a City or County Park on a seasonably hot Saturday afternoon in July or August. There are a few puffy white clouds, and everybody is hoping it doesn't rain on this year's Family Reunion. Of course, all the cousins will come with their “runny-nosed” kids, and several of us will get the flu from them, you know, the intestinal flu that makes you so miserable for a day or two. As the relatives show up, they bring food with them, usually whatever they are famous for and it's always good. There's Gramma's fried chicken and that really good potato salad of Aunt Ruth's. Uncle Frank will do the grilling: the steaks, hamburgers… and hot dogs for the kids. By the time the whole clan is here, there'll be a pretty darn good spread there on the serving table. After we catch up with the news from everybody, we'll “ring the dinner bell.”
Meanwhile, back at the ranch… in Nutrition class, we should look into this self-diagnosed intestinal flu. Flu is short for influenza which is a respiratory disease. When I taught A & P, the respiratory system did not include stomachs nor intestines so I'm a little confused by digestive system symptoms for a disease of the respiratory system. Let's take another look at that family reunion to see how the runny-nosed little brats could have transmitted the flu from their respiratory systems to the adults' digestive systems. Gramma's fried chicken was especially good this year, nice and crispy and those spices -yummy; but when did she fry her chickens. Those chickens were fried yesterday evening, let to cool on the counter [and pick up a few Salmonella spores], then put in the ‘fridge’ [to incubate slowly] until it was time to go to the reunion. Then the chicken was loosely covered with foil and put on the back window ledge (or back seat) in the car [where solar heat raised the temperature, speeding up the incubation], carried from the car to the picnic table [allowing a longer incubation time, producing a good culture by the time the meal ended]. Of course, if there was left-over chicken, somebody took it home to eat later. How 'bout Aunt Ruth's potato salad; when was it made? Well, that would have been two nights ago, it's gotta age for at least 24 hours to be that good. So the mayonnaise [the real kind, made from egg whites] in the potato salad has had about 36 hours of slow incubation followed by a coupla hours of faster incubation. Since mayonnaise is a good culture medium for Salmonella, there is a chance that a good culture has grown already by the time the left-overs are taken home to eat later. I am willing to guess that the beef (steak and hamburgers) were refrigerated for at least two days (48 hrs), then stored out in the sun for two or three hours, cooked rare to medium rare [without a meat thermometer], and served [with a decent culture of Clostridium botulinum marinating the meat in botulinum toxins]. On top of all that, it is extremely unlikely that the surfaces on which the food is served and eaten were not contaminated. So, where oh where can the self-diagnosed “intestinal flu” have come from -surely not the salmonella toxins nor the botulinum toxins; it's just gotta be the runny-nosed little brats. [by the way, some completely useless trivia: brat is the Russian word for brother, so if you have a brother, he really is a brat].
    During A.D. 2002, there were 76 Million reported cases of foodborne illness (viruses, bacteria, and parasites) in the United States, 325 thousand of which involved hospitalization; and there were 5,000 deaths attributed to foodborne illness (data from Wardlaw & Smith. 2007. Contemporary Nutrition, updated 6th ed., McGraw-Hill). Historically (as in my Grandmother's generation; she was born in the 1880's and lived about 100 years 3 months), most cases of food poisoning (now called “foodborne illness”) occurred in mid- to late- winter and were attributed to improperly preserved home canned foods (especially tomatoes, which are surprisingly good culture media for Clostridium botulinum; in fact my Grandmother had at least a few cans [Mason (or Ball, of Ball State University) jars] of tomatoes literally explode due to the build-up of pressure from gaseous by-products of Clostridium metabolism each winter, and Ball jars are very thick and hard to break by dropping them on stones. With the commercialization of home refrigerators, and resulting decrease in the need to do home canning to preserve fresh produce for the winter, this source of foodborne illness became less prevalent. In the 21st Century, the leading identified contributing factor to foodborne illness is improper food handling in general (preparation, storage, and preservation). Clearly, with 76 Million reported cases and an unknown number of self-diagnosed intestinal flu cases which are actually mis-diagnosed cases of foodborne illness, this is a large amount of avoidable illness. Thus, it would be useful to use Nursing education as a means to reduce the incidence of the problem among those patients who disclose the self-diagnosis of chronic intestinal flu to their Nurse. The other major factor in food borne illness is “environmental contamination,” but is unclear to me how Nursing intervention/education can be expected to have a significant impact on the incidence of this problem.

food preparation

Personal and environmental hygiene is the first step in reducing foodborne illness. Translated into English, this means that the food preparer should maintain good hygiene (such as washing hands) and a clean environment (counters and utensils). I should caution you to avoid encouraging (or engaging in) obsessive cleaning in the kitchen; it is not possible to create, much less maintain, a “sterile field” in a home kitchen. Most home kitchens do not even have doors, and the few that do don't have doors that seal; nor sufficient positive pressure (a HVAC technical term for greater air pressure on the inside of a door than on the outside of the door) to prevent airborne viruses and bacterial spores from entering the room. And most home kitchens have a continual stream of non-scrubbed personnel entering and leaving at random intervals. Because of the continuous re-contamination of all kitchen surfaces, it is unnecessary to use disinfectants. [I had a microbiology lab test a popular brand of disinfectant hand soap by spraying the soap on one of two plates, then transfering cultures of bacteria collected on surfaces at the college. Of the students who were able to get transfered cultures to grow, 50% reported decreased growth on the treated plate, while the other 50% reported increased growth on the treated plates. The only statistically valid conclusion is that the antibacterial hand soap has NO effect on bacterial growth; although disinfecting products flushed into septic systems have been shown to kill the septic tank by killing the beneficial bacteria (the ones that disgest the wastes flushed to the septic system).] So, what we need to establish is a “routine” for food handling, without the obsessive/compulsive part. Speaking of contaminated items around the kitchen, the worst, by far, offender is the kitchen sponge (personal communication, from the New Mexico State Health Department Director, circa 1960); once used, the sponge cannot be cleaned due to all of the hidden nooks and crannies inside the sponge [more than a Thomas' English Muffin™ has].
    The recommended routine is for the food preparer to begin by wiping the counter surfaces with a moistened paper towel [neither a wash cloth nor a disinfectant wipe], then washing their hands. We are now ready to get out one, and only one, food to be prepared; and open the packaging. Fresh fruits and vegetables should be washed; prepackaged foods need not be washed, but it wouldn't hurt to rinse your hands to remove bacteria from the packaging. Prepare the food as usual, then re-wipe the counters with a new paper towel, clean any utensil you intend to use again, and wash your hands. Now you are ready to get out the second food item.
  Obviously, this routine is going to work best if you happen to have Rachel Ray's stage crew assisting you. The patients who qualify for a OCD (Obsessive-Compulsive Disorder) diagnosis will like this procedure, but for the rest of us, this routine will quickly become sufficiently annoying that we will become non-compliant. However, I have discharged my duty to tell you the recommended routine. Realistically, you must wipe up (paper towel, not contaminated wash cloth) any fluids from the previous food to reduce (not eliminate) cross-contamination. One ad suggests that their paper towels can be reused to pick up additional spills; this defeats the purpose of using paper towels. The idea is to discard the bacteria which you just wiped up. If it concerns you that my suggestion will lead to a huge volume of used paper towels headed for the land-fill, you could recycle them, or better throw them in your compost pile [but your down-wind neighbors probably won't like this solution to “greener living;” in case you've never smelled a compost heap, they are only slightly less smelly than a well used cat litter box].

    The next step in reducing foodborne illness is the cooking itself. The current guidlines (USDA) include specific minimum cooking times for many foodstuffs and minimum internal temeratures (measured with a meat thermometer). Again there is more than one way to be compliant with these guidelines. You could go paranoid, and overcook everything so your food will lose all semblance of taste, and will have all vitamins destroyed, so you can compromise your wellness [and live a short but miserable life]. Or you could go the OCD route, and check the internal temperature so often that the cooking temperature never reaches the guidelines, extending the cook time. Or you could use my approach, which is to take reasonable precautions to minimize the risks of foodborne illness, and cook to personal taste and texture, [and outlive all the paranoid and obsessive-compulsive types, and have more enjoyment out of life].

food storage

Most packaged foods now have either a “sell by” or “best by” date stamped on the package (but it is often hard to find). The bad old days of coded expiration dates are pretty much a thing of the past. ‘Sell by’ dates are very useful to grocers, but a bit confusing for most people. By definition (USDA regulations) food products are not to be sold, starting the day after the sell by date, but may be stored at home (assuming proper conditions such as temperature, exposure to light) for a reasonable time. The actual regulations quote “reasonable storage times” for a number of products. For example, milk (and some other dairy products) have a shelf-life of three days after first opened; but only one week from sell by date to be opened. Fresh meat has a shelf life of one to one and a half weeks refrigerated, and three months maximum if frozen after purchase. Unfortunately, other than college professors of Nutrition and of Microbiology preparing for lecture on safe food storage practices, I have yet to meet anyone who looked up ‘reasonable storage times’ on purpose (and I even have friends/relatives who almost qualify as paranoid OCD when it comes to food and food-like substances).
    The newer “best by” dates are the most user-friendly labels; the ‘best by’ date is approximately the date on which the risk of spoilage has become sufficiently high that the remaining food in the container ought to be discarded. Yes, it would be better if we could label food with an absolute deadline for discarding, but there are too many variables affecting the rate of spoilage, and some products become dramatically less appetizing on or near the best by date (although some of these will have considerable “safe” storage time remaining at a reduced quality). There are a couple of exceptions to the vagueness of reasonable storage. I recommend that yogurt be treated as if the sell by or best by date is the absolute last day for storage; yogurt contains live cultures of bacteria, whose metabolites are toxic. When the bacteria die, it is because the concentration of toxins has exceeded the fatal concentration for the bacteria. The other exception are Twinkies™ snacks. At the peak of the Cold War, it was stated [by stand-up comedians] that the only things that would survive a global nuclear war would be cockroaches, tupperware and twinkies. I have challenged Biological Concepts for Teachers students to grow mold on twinkies by declaring that it can't be done. So far, no one [myself, nor students in my classes] has successfully caused bread mold to grow on Twinkies. Twinkies have been stored for decades with no apparent change in quality. I recommend discarding those twinkies handed down as family heirlooms for no less than five generations, although they will probably still be good for a several more centuries.

preservation

Historically, or more accurately prehistorically, our hunter/gatherer ancestors discovered that some fruits and meats could be preserved by sun drying, giving us things like raisins (sun dried grapes) and jerky (sun dried meat strips). Grains are also dried, usually air dried, for preservation. Over the early years of civilization, we developed other methods for preservation of meats by dehydration, using enough heat to cook the meat. These include smoking, salt curing and sugar curing. And as the name implies the sandwich spread called “preserves” is heat-dried (slow cooked) berries stored in closed containers. Other similar preserving methods (slow cooking) for fruits produce jams and, with the addition of pectin (extracted from slow cooked apples), jellies.

    The second major advance in food preservation was home canning (in Mason Jars, also called Ball Jars [manufactured by the Ball Family in Muncie, IN; the same family that endowed Ball State University]). The process for home canning developed out of an elegant experiment intended to disprove spontaneous generation. During the Middle Ages [previously known to Liberal Arts college students as the Dark Ages], it was generally believed that life could appear “spontaneously” from non-living things; such as, frogs arise from mud, dirty rags left in the dark back of the pantry would turn into baby rats, and maggots form from rotting meat. Then, in A.D. 1668, Francesco Redi devised an experiment to disprove this. He put lumps of boiled meat in jars. Some jars were left open, the others were covered with two part lids (one part was flat with a rubber gasket to seal it; the other part screwed onto the jar to close the first part tight against the jar (the familiar Ball Jar). The open jar soon had flies around it, followed by maggots on the meat; the closed jar had neither maggots nor flies. The Church countered that the sealed jars prevented the souls of the maggots from enteriing the meat to cause the formation of maggots. Redi reran the experiment adding a third type of jar with cheesecloth held on with the screw cap. The third set of jars had flies around it, but no maggots. The Church sent the song-and-dance routine known as the Spanish Inquisition [“No one expects a Spanish Inquisition”] which offered Redi the choice of recanting his conclusions or being burned at the stake. A few years later, during the Reformation, Louis Pasteur ran a less elegant experiment in A.D. 1859, and is credited with proving that spontaneous generation does not occur. Redi on the other hand basically invented a method for preserving food by boiling and sealing in jars.
    In the mid 19th Century, the ice box was invented as a device for storing food for relatively short periods of time (weeks). It was replaced by Carl von Linde's invention of the refrigerator in 1876, then by more efficient refrigeration equipment capable of freezing food for longer storage times (months). The most recent advance in food preservation has yet to be successfully commercialized, and involves irradiating the food to kill all bacteria. Chickens, cleaned and dressed as if to be cooked whole in the oven, were sealed in plastic bags and irradiated. These chickens have been opened after decades of storage at room temperature, and shown to be free of bacterial contamination. The chickens do not glow in the dark (as everyone thinks they would) nor are they radioactive (as everyone thinks they should be). One of the team members in the study told me that the 30-year old chickens tasted as fresh as a recently killed chicken from the grocery store.

environmental contaminants

Environmental contaminants include the usual laundry list of “things some people like to worry about” as evils of modern living:
      1. pesticides & other ag chemicals
      2. ‘rodent hairs’ & ‘insect parts’, permitted in processed foods by USDA regulations
      3. potential allergens from food processing, such as peanuts and peanut dust
      4. other…



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revised: 21 May 2009

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