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How to get started

You should start to download the “Handbook of how to measure respiration”, the handbook can be downloaded in the members area (using your login) or you can download it under demo tools, you will be asked to to inform your contact data in a form before you can start downloading.  

You must have the relevant equipment, which is described in the Danfresh handbook. We recommend the measuring equipment for example Check Point 3 from Ametek Mocon.

You also need to have a refrigerator or cold room where you can have a stable temperature (+/- 1 to 2 degrees C), We recommend to measure the respiration at the same temperature at which the product is commercially displayed on store shelves (as the product has the longest stay in a retail store). The calculations offer a function where you can simulate and calculate at different temperatures, but the accuracy of the calculations and simulations will be less if the temperature differences increase.

As a default guideline, you should fill up the measuring respiration jar as full as possible leaving only 1-2 cm of headspace. Below the closure.  This will in most cases secure a good balance between product and head space.


If you have a fast-respiring product and/or if the rate of drop in oxygen (or rate of increase in CO2) measuring process goes too fast, then you can reduce the quantity of the product in the respiration jar to increase the headspace. On the other hand, if you have a slow respiring product, then it can be beneficial to add more product in the respiration jar or reduce the head space further. You should find your best compromise based on the data you begin to see.

A typical respiration test can take from 24 and up to 96 hours depending on the product. If tested at low temperature it can even take longer. The fastest test we ever had was with asparagus and brussels sprouts as it took less than 24 hours.


It is recommended to measure the same product in a minimum of 2 separate respiration jars (or even more respiration jars) at the same time. Care should be taken to fill same amount of product weight in both or all respiration jars. If you use an average respiration data from two or more respiration jars, it will give you better and more correct results.


Remember to always clean the respiration jars before each use.


You should never eat products that has been tested, as your product would have been contaminated. Also, during the respiration testing, product O2 level can get very low (zero), creating anaerobic conditions which can cause off odor, sliminess and as such the product is not safe to consume.  


If you are testing mix products like a salad made using different components, then it is   important to know the respiration of the final mix. Always note exact percent of each of the components used for later use. We recommend two different ways to measure respiration of mixed products


1. You can measure each single product as described in the handbook, and when you calculate the level of respiration of the final mix, you can calculate the percentage of each product of the final mix. This will give you good information about the respiration, and if you want to change the percentage of some of the products in the mix at a later stage, then you can just make a new calculation and you don’t need to make a new respiration test again.


2. You can also measure on the total mix as a final product. Just pack a sample of the final mix in some respiration jars, and after finalizing the test you have the respiration data for that specific mix. If you want to change the percentage of some of the products in the mix at a later stage, then you have to make a new respiration test on the new mix.

We recommend that you use option 1 so that you don’t have to repeat the respiration tests and simply use the respiration data for each of the components and note the percentage of the components used

You should continue to measure the level of O2 and CO2 in the jar until the level of O2 and CO2 is out of relevance or until end of the product lifetime. One example on strawberries, based on our experience the level of CO2 in the final package should not go above 10%. In this case, We would recommend continue measuring until the CO2 transcends maybe 15 or even 20 %. At the same time, the level of O2 will have dropped to between 5 and 0%. If you continue to measure until that stage, you will have a very good picture of the respiration of your strawberries. 

Please note the change in the levels of O2 and CO2 during respiration. If the level of O2 decreases by 5 %, then in typical cases the level of CO2 will increase to about 5 % also, if the level of O2 drops with 10 %, then the level of CO2 increases with about 10% and so on. In most cases there is a close connection between the changes in O2 and CO2, i.e., if one goes down the other one goes up.



Please note that the respiration test does not show any possible extension of the shelf-life of the product. The respiration test is only to generate respiration information about the tested product where this data can be used to calculate and simulate "what happens if". You can change some of the many factors in the packaging design like choice of material, perforation, temperature etc.   

If you have any questions, please contact us by using the chat option or contact form on this website.

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