Put them in the freezer… but how long will they remain good for?
The shelf life of a product has been reach when one of the quality attributes (flavor, texture, color) is no longer at an acceptable state. Food products change during storage but only when the changes reach a certain point do we say the shelf life has been reached. Small changes in quality are often acceptable.
Frozen storage changes the flavor
The main quality attribute that is likely to change during frozen storage of crickets is flavor. There are a couple pathways for flavor changes to happen.
One mechanism is freezer burn – Freezer burn happens when frozen moisture in the crickets sublimates. This leaves patches of dehydrated cricket. The dehydrated areas are much more susceptible to oxidation resulting of off flavor. Crickets have a high surface area to volume ratio so this is definitely something that can happen. Water can also recrystallize affecting texture.
Second is bacterial/enzymatic activity – Raw crickets have bacteria on them as with most raw animal products. Some bacteria are still active at frozen temperatures (but much slower). Bacteria also contain enzymes that can speed up changes. There may also be enzymatic activity happening from cricket enzymes originating in the digestive organs. Eventually bacteria and enzymatic action are going to cause unwanted changes in flavor during prolonged storage.
2 Solutions To Extend Shelf Life
Apply a heat treatment before frozen storage to decrease bacterial load and denature enzymes. Blanching for 2-3 minutes would do the trick. Most vegetables are blanched before frozen storage to inactivate enzymes. Heat treatment will also denature the meat protein so if someone wanted to make sausage, they would need to add some other binder.
Glazing crickets in ice provides a protective coating and limits oxidation. This is done by spraying frozen crickets with ice cold water until a glazed is formed. Alternatively, crickets can be dipped in an ice bath and refrozen. Glazing is commonly used for seafood. Here is a link for glazing basics Seafish.org – Glazing.
Shelf Life Estimates
I looked at data for shrimp and also lobster and crab to support these estimates. These are estimates and and I have not performed any testing.
|Crickets||Home Freezer 0F||Commercial Freezer -18F|
|Raw||1-2 months||3 months|
|Raw Glazed||3 months||4.5 months|
|Cooked||3 months||4.5 months|
|Cooked Glazed||5 months||6 months|
How to test shelf life:
Like I said, these are just estimates. We need to start accumulating data. There are a lot of technical considerations to consider when executing a shelf life test. Here are some steps to get you started.
Decide how often you will make an evaluation. Testing once a week should be about right.
At the start, freeze packaged crickets. Make sure you freeze enough crickets.
Evaluate crickets right away on day 0 and on day 1. Some changes might already have taken place due to the freezing process. Take note of flavor, texture and appearance.
Follow the same cooking method as precisely as possible for each evaluation.
Evaluate at set intervals. Also prepare freshly frozen crickets so that you have a comparison. This may not always be feasible so refer back to your notes.
Note when the quality has deteriorated to the point where it does not meet your standards.
Most importantly, share the results and include lots of details like the temperature of your freezer and packaging. Post any shelf life results in the comments section here or send me a message.
Shelf life information is important not just for consumers but also for farmers and processors.