The solutions selected are often the most elementary ; this is not necessarily a bad thing in the area of food safety, where ignorance and misunderstanding are endemic. An excellent example can be found here in the Puget Sound where pro bono publicumbillboard advertising and King County Metro and Pierce County Transit bus advertisements decry the lack of handwashing and advise that better health results from washing hands after using the restroom.

Risk management with respect to food safety is complicated by the same factors that complicate risk assessment - namely, the nature of the beasties makes any absolute prediction impossible. Let's look at some examples to see just what obstacles confront food safety risk managers.

• Salmonella spp. causes nausea, vomiting, abdominal cramps, minal diarrhea, fever, headache, and, chronically, arthritis. Onset time is from 6 to 48 hours and infection may be caused by as many as 15 to 20 vegetative cells. Two to four million cases occur annually in the United States.
  
  
• Clostridium perfringens causes intense abdominal cramps and diarrhea within from 8 to 22 hours after exposure; it usually lasts only 24 hours. The dose-response appears to be at least 10⁸ vegetative cells.
  
  
• Escherichia coli 0157H7 in which as few as 10 organisms can cause severe abdominal pain and bloody diarrhea. The disease is self-limiting and lasts 8 days or less. In the immunologically compromised, one complication is hemolytic uremic syndrome (HUS), which is potentially fatal.
  
  
• Bacillus cereus - emetic B. cereus occurs from 0.5 to 6 hours after ingestion of foods contaminated by 10⁶ bacteria per gram and usually lasts only 24 hours. It is commonly found in vegetables and grains, especially rice.
  
  
• Giardia lamblia infection usually occurs within one week of ingestion of a single cyst; however, chronic infection can last from months to years. Usually a diarrheal disease but may involve the central nervous system.
  
  
• Staphylococcus aureus symptoms onset are rapid and acute, depending only on the individual's susceptibility to the toxin, and involves nausea, vomiting, retching, abdominal cramping, prostration, and may also include headache, muscle cramping, transient changes in blood pressure and pulse rate. A toxin dose of less than 1.0 microgram is sufficient to induce morbidity.
  
  
• Norwalk-like viruses (NLV'S) are the source of viral gastroentiritis, second only to the common cold in frequency of occurrence in the U.S.. The onset of symptoms occurs from 24 to 48 hours after infection. It is possible to develop immunity to NLV's and up to 50% of Americans do; unfortunately, the immunity does not last, even for the same serotype. This is what people refer to as "stomach flu".

These are just a few of the more common foodborne illnesses in the United States; if we include the rest of the world, the picture changes radically. If one looks at all the different characteristics of the beasties involved, one can readily appreciate the difficulties involved in trying to manage the potential risk each presents. Actually, new threats are emerging all the time. Twenty-five years ago, it was unclear that Clostridium perfringens was pathogenic for humans and Listeria monocytogenes and Campylobacter jejuni were of concern to veterinarians and those involved with animal husbandry, not the food industry.

The fact that Listeria monocytogenes has at least a twenty percent mortality rate has gotten its emergence as a human pathogen a great deal of attention very quickly.

So how, then, do we manage risk when we are confronted by such variation among our microbial adversaries? First let us ask, what is an acceptable level of risk? There is currently a 1 in 33,812 chance of becoming ill with salmonellosis from a typical meal. Assuming the typical American eats 3 meals per day, 7 days a week, that translates into that American contracting salmonellosis every 31 years.

Or, to look at it another way, in 1991 the average American dined out 3.8 times per week. If we were to turn to irradiation of meat and poultry to eliminate or greatly reduce the threat of foodborne illness, we would have to increase our food budget by $36 billion annually just to cover the increased costs of restaurant meals! This is assuming that irradiation will add $0.71 per capita cost to the meat or poultry portion of the meal.

There are those who argue that a certain amount of exposure to microbial pathogens and toxins is beneficial to the human immune system. While it is not possible to argue that an individual can develop immunity to Staphylococcus aureus, there is much that is not understood about the flora and fauna that colonize our gut and how they interact with invaders, change as the external environment changes, change with diet and water source, change by race, and so forth. Chickens are now innoculated with one bacterium to prevent the unchecked growth of Salmonella enteritidis that is characteristic of poultry.

Contamination of the American food supply generally occurs in one of four areas:

• Exposure to microbial infection at the farm level;
• Exposure to microbial adulteration at the food processing level;
• Exposure to improper food handling and food storage practices at the retail level;
• Exposure to improper food handling and unsafe food storage in the household;