Physical Hazards

• Physical hazards are those hazards which are due to the preparation and handling of food. This process starts from the food source. Animal and plant sources of food which are grown on a farm are subject to contamination from many sources. For instance; the soil contains numerous pathogens, microorganisms and chemicals which may be transferred to the food. The people harvesting the food may also contribute to food contamination by passing pathogens to the food. For example; if a worker does not adequately wash his hands after using the toilet, this may lead to the transference of pathogens to raw food like vegetables and fruit. Some people may also cough or sneeze on food as they handle it, or have infected cuts or sores on the skin. This can be combated if the farm or field is equipped with some hygienic facilities like hand-washing stations, toilets with hand sanitizers and if the workers wear gloves when appropriate.
  
  

Fish and Shellfish Hazards

• Fish and shellfish are in a category of their own, as they are raised on ponds, fish farms or are caught in the wild. Water contains a number of pathogens which can infect the fish and pose a threat to consumers. Fish caught in the wild are more susceptible to infection by pathogens than those raised in a controlled environment like a fish farm. Some fish that are caught in ocean water sometimes have Ciguatoxin, a pathogen contracted from feeding on dinoflagellates. Sometimes the fishermen who catch fish like mahi mahi, tuna and amberjack leave them on the decks of boats too long, leading to partial decay, allowing histamine to form. Histamine and ciguatoxin are not destroyed when fish are processed in canneries, or when prepared at home.
  
  

Chemical Hazards

• Chemical hazards are divided into unavoidable poisonous or deleterious substances and prohibited substances. Sources of chemical hazards include pesticides, growth hormones, processing aids, antibiotics, herbicides, color additives, and food additives. The USDA has a list of approved chemicals which may be used in the preparation of food.
  
  

Microbiological Hazards

• Microbiological hazards refer to those microorganisms which can contaminate food. Microorganisms can take various forms. Bacteria are single-celled microscopic organisms which can be killed by heat and the treatment of food with some chemicals. Viruses, mold, parasites and certain strains of yeasts are other microbiological hazards.