Is there any risk of illness from eating herbs or spices?

Very little. Depending on how they are farmed, harvested and processed, dried herbs and spices may harbor pathogenic such as E. coli O157:H7 and salmonella. That's because pathogenic bacteria may reside in the soil from which herbs and spices are cultivated. During harvesting, processing, and distribution, human hands can spread the pathogens from contaminated to uncontaminated plant specimens.
 
During processing, dried herbs and spices typically are subject to a kill step to eliminate pathogenic bacteria. More often than not, the method of choice is irradiation, which is highly efficient in treating herbs and spices. Some consumers cringe at the thought of irradiated food, even though irradiation was approved for use on herbs and spices decades ago. That's because the amount of radiation administered on herbs and spices isn't harmful. Additionally, more conventional kill steps such as heat pasteurization would degrade herbs and spices, both of which are heat sensitive.
 
Herbs and spices also may be subject to spoilage bacteria and mold growth, particularly when exposed to moisture. When herbs and spices are stored in cool, dry places, spoilage and mold growth shouldn't be a problem. Nor should pathogenic growth. That's because herbs and spices are dry, and bacteria and mold require moisture to grow.
 
Some dried herbs and spices contain preservatives to retard bacterial growth.
 
Source(s):
FDA "Spices, Condiments, Flavors, and Crude Drugs"
Questia.com "The Growing Use of Irradiation to Preserve Food"
Drweil.com "Food Irradiation: Is Zapping Herbs Harmful?"
Egyptian Ministry of Trade & Industry "Herbs & Spices"
Sciencedirect.com "Assessment of the microbiological safety of dried spices and herbs in the UK"