Disease processes in foodborne illness.

Although food seldom transmits illness, there are several known ways in which foodborne illness can occur. Everyone is susceptible to infections and intoxications, although some portions of the population are at greater risk than others. Infections result from eating food containing a viable organism that multiplies in the body, sometimes causing disease. Intoxications result from eating food that contains a substance that poisons the body. In addition to these more frequent types of foodborne illness, there are others that affect only a select portion of the population. Allergies occur when food contains a substance to which the consumer is hypersensitive (generally an adverse immune mechanism), whereas metabolic disorders (some of which are called intolerances) involve the individual’s inability to process food components that are successfully digested by others. Idiosyncratic illnesses are events that may or may not be caused by components of food and that affect rare individuals in ways that are not yet understood.