Food preparation and illness
Living a healthy lifestyle doesn't come without its risks. Eating foods with natural ingredients is key to maintaining our health. Upon adopting this "natural" lifestyle, we must learn to adopt proper ways of preparing natural foods as well. Although healthy, many foods, whether home-grown, or brought from your local market must be properly prepared and consumed. Why is this? We must keep in mind that there are parts of fruits, vegetables, and meats that can harm us if consumed.
As we discussed in the introduction, apple seeds contain cyangenetic glycosides, which release cyanide upon digestion. Many other foods also contain cyanide, such as the pits of cherries, peaches, plums, apricots, and others. It is important to understand that apples, peaches, etc., are safe to eat. It's the seeds (or pits), that we must avoid chewing. As children, many of us have chewed and swallowed apple seeds upon approaching the core. When we chew these seeds, we break open the "seed-coating", which releases the harmful cyanide-containing compounds. Swallowing seeds whole is less harmful, as we cannot fully digest the seed coating, and they pass through the digestive system into the waste. Or do they? Certain bacteria may contribute to digestion of the seed coat. Thus, it is better to be safe, rather than sorry and simply not consume the seeds.
Parents giving a child an apple for the first time can educate their children in these aspects before allowing their child or children to consume these products. If a child is too young to understand, it is recommended that the parent simply, cut the apple into slices, thereby, eliminating the core, seeds, and risk. Additionally, it decreases the probability that the child will accidently choke on a seed. Seeds (or pits) fro peaches, plums, cherries, and other foods can easily lodge between the larynx and throat, proving fatal.
There are other food which must be prepared with an air of caution as well. Most of us are familiar with the root named cassava. It is the ingredient used in gari (a popular food in the tropics, which resembles porridge), tapioca (which we eat as tapioca puddings), manioc, mandioca, yuca, and sagu (Manihot esculenta). Almost one-quarter of a billion people in the tropics consume cassava on a daily basis. Young roots may have one-third starch by weight very little protein or fat.
Almost 3000 years ago, cassava was used in early pre-Columbian times in Colombia and Venezuela as a food source. They probably learned through trial and error that consuming raw cassava could be a fatal experience. Cyanide-containing compounds in cassava cause illness or death by inhibition of the enzyme, cytochrome oxidase. Formation of an inactive complex of cytochrome oxidase and cyanide results in asphyxiation since oxygen cannot be utilized. Undoubtedly, it was learned that by boiling or squeezing (pressing) cassava, the cyanide can be removed. There are certain cultivars of cassava with lower percentages of cyanide, such as sweet cassava. But this is not entirely accurate, since percentages depend on genetics and growing conditions. Therefore, before consuming cassava, ensure that you are well aware of the correct methods of preparation.
Other foods that can harm us
In comparison to the cyanide-containing foods, there are other foods that contain substances which can also harm our health if eaten, or if the food is not properly prepared.
Fish and molluscs (shellfish) comprise a portion of the diet of many. Fish on the whole are safe, but there are certain species to err on the side of caution before consuming. Origin is another concern.
Ciguatera is an "umbrella" term for a ichthysarcotoxism, a medical term for "fish poisoning". This food poisoning is caused by the consumption of tropical and subtropical marine fish which have accumulated naturally occurring toxins through their diet. These toxins originate from several species of the dinoflagellates (algae, mainly the species of algae, Gambierdiscus toxicus) which flourish in these regions. Perhaps a more correct name for this malady is "ciguatoxinosis" or toxism, since ciguatera denotes the poisonous snail (Species originally, Taino), and not the toxin (ciguatoxin). Regardless of my opinion, the fact is this toxin accumulates in the tissues of several fish (barracudas, groupers, snappers, jacks, mackerel, triggerfish and probably other species). If these fish are eaten and happen to contain enough toxin, the consumer can become severely ill. I had the personal pleasure of living in the Caribbean (West Indies) for several years, and witnessed several people becoming very ill after mealing on a tasty barracuda. This toxin (the ciguatoxin) affects cellular sodium channels. Basically, sodium channels regulate sodium concentrations. If sodium is not properly regulated, any function dependant on sodium, logically goes awry. This is includes, most areas of the body, and individuals ingesting this toxin can develop arrythmias (irregular heart activity), neurological abnormalities (abnormal sensations), and other symptoms. Although there haven't been many deaths, there have been some. I'm not suggesting to boycott tropical fish, but rather adding guidance in choosing certain types in regard to location and the risk involved.
Elasmobranchs are any cartilaginous fish, such as sharks, skates, rays and sawfish. Aside from some of the toxins they can contain, certain sharks can cause general stomach upset and nausea from products of their metabolism. Dogfish sharks are high in uric acid, and basically taste awful. I used to catch them off the coast of North Carolina, and I can personally attest to this. One of my professors at the time suggested soaking the shark steaks in baking soda, but this did little.
Scombroidea are a suborder of marine fish having oily flesh, including mackerels, tunas, bonitos, albacores, and skipjacks. The flesh of these fish may contain a toxic histamine-like substance, which, if ingested, can cause what is known as scombroid poisoning. Keep in mind that scombrotoxin is formed from the action of bacteria on histidine, a normal component in the flesh of fish. Scombroid poisoning is seen when fish are inadequately preserved. Therefore, be sure that you are thoroughly familiar with preserving methods in regards to fish before storing fish for consumption at a later date-or you won't be too popular with your guests.
The genus Gymnothorax is comprised of eels. Certain types of moray eels can store toxins in their flesh, which can result in severe illness.
In any discussion of food preparation and illness, we must address food poisoning in general. In our discussion of potentially poisonous fish, we must keep in mind that the toxins which accumulate in the tissues of the fish, are chemicals. This is different to bacterial food poisoning, which occurs when bacteria are present in a food and can be consumed. Of course, bacterial toxins can accumulate as well, and this is also regarded as food poisoning. However, we wanted to make clear the distinction between bacterial food poisoning and ichthyosarcotoxisms.
Bacterial food poisoning is something that we must consider with any food. Bacteria are ubiquitous (found virtually everywhere), and if they are not on the food source by the time it reaches our kitchen, we transfer bacteria from our hands to the food anyway. This is not a concern if we are going to immediately cook the food. However, if we handle a food product, and leave it at room temperature for several hours or more before consuming, we pose the risk of food poisoning to both ourselves and others who may consume the food in question. If bacteria are allowed to multiply on a food, they too, can produce toxins which can make us very ill. Although cooking kills bacteria present on the food, it does not inactivate the toxins on the food which the bacteria have produced. The best way to avoid illness in regards to food poisoning, is to either quickly refrigerate food until cooking, or immediately cook.
"In vogue" fish products such as sushi (raw fish) also present a potential hazard, considering the risk of parasitic infection.