STEM Food and Food Borne Disease

Transformation Decorators

Modeling diseases transmitted by food first requires the ability to model food and food production. Certainly livestock or crops can be represented by a Population Model, as can the food itself. The rate at which animals reproduce can be express modeled with existing birth rate and death rate properties. Crop growth rates might be based on climate data plugins. Food itself (meat, barley) can also be represented by a Population Model, using new parameter or representing spoilage or expiration by a death rate. As abstract populations, both food and food sources are continuous variables that be represented as STEM Integration Decorators. However, to support modeling food production it is also necessary to model the transformation of livestock and living agricultural products into food. To support this in the most general way possible STEM provides a new kind of decorators called a Transformation Decorator with the following properties:

• Transformation Decorators can transform one population into another (e.g., cattle=>beef)
• Transformation Decorators handle mapping of (disease) labels associated with one population (cattle) into (disease) labels associated with another population.
• A transformation decorator can then represent disease transmission by mechanisms other than contact or mass action. A crop infected with mold may transmit micotoxin to grain as it is converted into grain.

Instances of transformation decorators are "Food Producers" such as a Slaughter House. A "Food Consumer" object might represent a food distribution site (market) or other processing or storage facility.

Food Borne Disease

Food Producers map populations to populations and diseases in populations to diseases in another population. This is important because animals might be able to recover from a disease like Salmonela but processed food if infected might never "recover". As such different classes of models may be required to model the same disease in a food source than in the food itself. For example, Salmonellosis as an SIR model in pigs and an SI model in pork.They may themselves become contaminated thus action as vectors of transmission.

Examples

• (New!) Scenario Structure: tutorial with templates
  • Model of food production and food borne disease
• Downloadable scenarios
  • Beef production example
  • Salmonella in pork example