Colorado Integrated Food Safety Center of Excellence

Innovations in Routine Investigations and Surveillance

Online Surveys to Supplement Routine Case Investigations

In 2019, the Colorado Food Safety CoE piloted the use of online surveys to supplement routine Giardia case investigations in three local public health departments. Investigators offered Giardia cases the option of either a telephone interview or an online survey. The results of the pilot project indicated that using online surveys for routine case investigations substantially reduced public health staff time spent interviewing; however, the time from case report to interview completion increased and data quality slightly decreased. The results were published in 2021 in Foodborne Pathogens and Disease (White, A., et al. Using Online Surveys for Enteric Disease Case Investigations: A Pilot Project. Foodborne Pathogens and Disease. 2021.

In 2020, with limited staffing available for enteric disease interviewing due to the COVID-19 pandemic, Colorado expanded the pilot statewide for all Campylobacter cases. From June 2020 through August 2020, Campylobacter cases were only offered the online survey. Starting in September, all Campylobacter cases were offered the option of either a telephone interview or online survey. The Campylobacter REDCap survey and a general protocol are available below.

In 2021, Colorado began making the online survey option available to Salmonella cases during times of need (e.g., staff shortages, outbreaks, etc.). Though not routinely offered to Salmonella cases, the online survey option has been a valuable alternative for cases who are reluctant to complete the interview by telephone, speak Spanish as their primary language, or have a condition that makes phone interviews challenging (e.g., deaf or hard of hearing). The Salmonella REDCap survey and a general protocol are available below.

When are online surveys a good tool to supplement telephone interviews?

  • If you have a high number of cases
  • If you have limited staffing
  • To supplement phone interviews
  • For cases who do not answer the phone or don’t have time to complete a phone interview
  • If phone is not an option (e.g., cases that do not have a phone, are deaf or hard of hearing, or are traveling internationally)
  • If a case does not speak English, an online survey may be easier than using an interpreter
  • For lower priority pathogens that are less likely to be associated with an outbreak

When should online surveys NOT be used?

  • If your agency has the time or resources to do the interview by phone

  • If a case works as a foodhandler or healthcare worker, or if a case is a childcare worker or attendee

  • If a case is suspected to be part of a cluster or outbreak investigation

  • If a case is unwilling to do an interview online, or if they do not have access to internet

  • If a lot of education is necessary

  • For higher priority pathogens that are more likely to be associated with an outbreak

Getting started



© 2023 Colorado Integrated Food Safety Center of Excellence. All rights reserved. Used by permission only.