Causes & hazards of smelly disaster waste, and food safety

 
        After the passage of a horrible typhoon, tremendous amount of disaster waste stinks. The stench is produced in the bacterial decomposition of organic matter of garbage. 75-80% of domestic waste is organic matter which includes leftovers, peels, leafy stalks, fur/viscera/fat/feces/blood of poultry/animal/fish, flowers, foliage, waste paper, and a certain amount of moisture. During the natural digestion process, a large amount of stench is produced in the process of aerobic or anaerobic fermentation (Figure 1). Especially in hot summer, high temperature speeds up the fermentation and the odor becomes smellier.
 
        The smell of domestic waste contains ammonia, hydrogen sulfide, organic amines, organic sulfur, and volatile fatty acids, etc. (Figure 2). Due to various odorous substances generated from a wide variety of sources, it may cause varying degrees of harm to the respiratory, digestive, cardiovascular, endocrine, and nervous systems of human body. Among all the substances, aromatic compounds such as benzene, toluene, styrene, etc. (Figure 3), may also cause human body distortion and cancerization. It is advisable to wear a face mask to avoid or reduce inhaling harmful substances.
 
        Rotten animals, plants and garbage can easily encourage pest infestation, resulting in the transmission of infectious diseases. Generally, if there are no open wounds on human bodies, direct dermal contact with contaminated food, water, garbage will not cause diseases. However, it is suggested to wear a mask in order to prevent respiratory infections, such as flu.

        Mold: After being soaked in flood water, mold tends to develop on many items. Mold is a common name for filamentous fungus, meaning “moldy fungus”. Molds are a group of fungi that thrives quickly in a warm and humid environment; many moldy objects are covered with some fluffy, flocculent or cobweb colonies that can be seen by the naked eye. These are called molds which can trigger allergies and asthma, and cause serious health problems. The action to remove mold should be quick and lasting. Clean and dry all surfaces of clothing, furniture, etc. as soon as possible. Clean the moldy area with 1:99 diluted household bleach (i.e. mixing 10 ml bleach with 1 liter of water), then dry it thoroughly. Protect yourself by wearing gloves and face mask as appropriate, always wash your hands with soap and warm water after cleaning. (Bleach should be used with caution as it irritates the mucosa, skin and respiratory system. It will decompose under heat or light, and readily react with other chemicals. Improper use of bleach may reduce its effectiveness in disinfection, even cause accidents which can be harmful to health.)

To ensure the health and safety of the public, the following requirements should be noted after a typhoon :

1. Personal hygiene practices: Hands must be washed with soap before/after handling food, before eating, and after using the toilet. Rub hands with alcohol-based handrub in case the supply of clean water is inadequate or the water is visibly soiled.

2. Safe potable water: boil water to a full boil. Many people are used to turning off the fire when the water is at a gentle boil; actually, this is not quite right. Not all bacteria can be immediately killed in a gentle boil. It is recommended to remove the kettle lid when the water is simmering, continue to boil water for 2-3 minutes, then turn off the fire. In this way, the bacteria can’t survive boiling boil and the water is much safer to drink. (Note: Don’t boil water for too long either, the longer the boiling time is, the more nitrite will be produced in the water. It will do harm to human kidney.)

3. Food safety: food starts to deteriorate as soon as the crop is harvested or the animal is slaughtered. The rate of deterioration is related to the growth of spoilage bacteria and mold. Most pathogenic bacteria grow and multiply rapidly at temperatures between 4^oC and 60^oC. At temperatures below 4^oC or above 60^oC, bacterial growth slows down or stops (however, most bacteria can survive cold temperatures and resume multiplication later when conditions become suitable again). Hence both raw and cooked food should be kept at or below 4^oC, or at or above 60^oC to suppress growth of such bacteria. During a typhoon, many refrigerators in residential houses as well as the refrigeration and freezing equipment of related industries were affected due to power outage. If the stored food is found to be spoiled (abnormal appearance or suspected contamination), please do not eat or process it for sale. That is because the spoiled food may still cause food poisoning or other symptoms even after heat treatment. Please note that the refrigerators, refrigeration and freezing equipment should also be thoroughly disinfected before re-storing food.