The soft plastic seals inside the twist-off metal lids on glass containers are the origin of semicarbazide. These types of containers are commonly used to hold jams, honeys, sauces, ketchup, baby foods, fruit juice, mayonnaise, mustard, and pickles. The soft plastic seals are desirable as they keep moisture and microbial organisms from entering the container during shipping and storage. While the toxicity of semicarbazide is uncertain, food manufacturers have increased testing to determine its migration into food. Extraction, derivatization, cleanup, and HPLC analysis are suitable.