Edible film kills bacteria in seafood
While it's important to keep food of any type fresh, it's particularly crucial with seafood, as it can become tainted with toxic bacteria. That's why an international group of scientists is developing a transparent antibacterial film that gets eaten along with the seafood it's covering.
The research is being conducted by scientists from Pennsylvania State University, along with colleagues from Thailand's Prince of Songkla University, Kasetsart University, and the Thailand Institute of Scientific and Technology.
Their film starts out as a clear gelatine made up of cassava-derived starch and a biodegradable polymer known as polybutylene adipate-co-terephthalate (PBAT). Added to this mixture are the antibacterial agents Nisin Z and lauric arginate (LAE).
The idea is that pieces of seafood get dipped into this gel – which subsequently dries into a form-fitting flexible film – after which they're vacuum-packed and then chilled or frozen. As they sit in storage, the antibacterials gradually proceed to kill any harmful microbes that may be present.
In lab tests, slices of big-eye snapper and tiger prawns were intentionally inoculated with E. coli and two types of Salmonella bacteria, then coated with the film, and then vacuum-packed. They were subsequently either left chilled at 4 ºC (39 ºF) for up to one month, or stored frozen for 90 days. When they were analyzed after this period, the bacterial populations were found to be greatly reduced.
The scientists are now exploring methods of commercializing the technology.
Lead scientist at Penn State, Prof. Catherine Cutter, has previously developed another edible antibacterial coating containing essential oils and nanoparticles. The US Department of Agriculture is also developing a milk-based film, while the National University of Singapore is making one from a compound found in crustacean shells.