People commonly use ice to keep food cold because of convenience, efficiency, and low cost, but water from melting ice can lead to cross-contamination and germ growth. Also, ice packs contain potentially toxic chemicals, and have a plastic shell that contributes to plastic waste. In a study published in ACS Sustainable Chemistry and Engineering, researchers from UC Davis used gelatin to make jelly ice cubes, plastic free, non toxic, and reusable alternatives to traditional ice cubes that can also reduce cross-contamination.  

The jelly ice cubes were most effective at temperatures below zero, because they tend to lose water at higher temperatures. To test whether the jelly ice cubes reduced cross-contamination, the researchers used dye to simulate contaminants, and observed how the dye spread. The jelly ice cubes did not leak any water containing dye, while melted traditional ice was dyed at the end of the test.

While the jelly ice cubes are totally plastic-free, they are unfortunately only partially reusable. The researchers found that although they could be reused for five cycles without physical damage, they lost water and strength over these cycles, reducing their usability. Also, the cubes need to be sanitized with either a water or bleach wash between cycles, which can potentially transfer bleach to food, raising toxicity concerns. These jelly ice cubes are an innovative idea, but their practicality needs to be improved before they can be seriously considered as an alternative to traditional ice cubes or ice packs.