Which factor does NOT contribute to the increase in food borne illness spread globally?

The factor that does not contribute to the increase in foodborne illness spread globally is the expansion of markets for local foods. This is because when food is sourced locally, it often involves shorter supply chains, which can reduce the opportunities for contamination that may occur in longer, more complex distribution networks. Local foods are typically consumed closer to the point of production, allowing for better control over food safety practices.

Additionally, local markets may have stronger community ties that promote accountability and transparency in food handling, further mitigating risks associated with foodborne illnesses. In contrast, the other factors listed, such as increased litigation, improved distribution channels, and the growth of convenience foods, tend to create additional complexities and risks that can lead to a rise in foodborne illnesses.