There's a frog in my salad! A review of online media coverage for wild vertebrates found in prepackaged produce in the United States

Daniel F. Hughes, Michelle L. Green, Jonathan K. Warner, Paul C. Davidson

Research output: Contribution to journalReview articlepeer-review


Prepackaged leafy green vegetables represent one of the fastest growing segments of the fresh-produce industry in the United States. Several steps in the production process have been mechanized to meet the downstream demand for prebagged lettuces. The growth in this market, however, has come with drawbacks, and chief among them are consumers finding wild animals in prepackaged crops. These incidents may signal an overburdened produce supply chain, but we currently lack the information needed to determine if this is a food-safety problem or food-quality concern. Here, we address this gap by reviewing online media coverage of wild vertebrates found in prepackaged produce items by customers in the United States. We discovered 40 independent incidents since 2003 with 95% having occurred during 2008–2018, suggesting that the frequency of incidents may have increased during the last decade. The minority of incidents included wild animals found in organic produce (27.5%), whereas the majority involved conventionally grown crops (72.5%). Most incidents involved amphibians (52.5%) and reptiles (22.5%), while fewer contained mammals (17.5%) and birds (7.5%). Frogs and toads made up all of the amphibian-related incidents, with more than 60% comprising small-bodied treefrogs found in various types of fresh leafy greens. At least seven incidents involved Pacific Treefrogs (Hyliola regilla) and three comprised Green Anoles (Anolis carolinensis). One lizard and nine frogs were found alive, and at least two frogs were released into non-native areas. This is the first review quantifying incidents of vertebrates found by customers in prepackaged produce, yet it remains unclear whether these occurrences indicate a food-safety crisis or a complaint against food quality. Nevertheless, wild animals can spread diseases to humans via contaminated produce, therefore we contend that industry professionals can reduce the potential health risk to their consumers and negative economic consequences to themselves through increased attention to this matter.

Original languageEnglish (US)
Pages (from-to)1-12
Number of pages12
JournalScience of the Total Environment
StatePublished - Jul 20 2019


  • Agriculture
  • Amphibian
  • Food safety
  • Online news media
  • Prepackaged salad
  • Reptile

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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