Most poultry vaccines applied in the hatchery today, including frozen vaccines, are kept in liquid nitrogen (-196°C; -320°F) to maintain the integrity of live cells. The vaccines and liquid nitrogen are stored in containers called Dewars. 

The transport of the vaccine is the most sensitive part of the vaccine journey between the production plant and a hatchery. To ensure use of a well-preserved vaccine, find below the 3 points of attention to control the integrity of the vaccine upon reception.

1. Aspect of the Dewar

First, check the general aspect of the Dewar. Look for any frost on the Dewar indicating a leak of liquid nitrogen. Also, control if there is any visible breakage or damage.

2. Level of liquid nitrogen

Then, measure the level of liquid nitrogen by slowly entering an adapted measuring stick in the Dewar. When removing the stick, a part of the stick will appear frosted, indicating the level of liquid nitrogen. Verify that the level of liquid nitrogen complies with the guidelines to ensure vaccine integrity.

3. Ampoule testing

Ampoule testing consists in the verification of the cold chain by controlling the freezing state of some ampoules.

In each Dewar, quality ampoules will be found upside down in order to perform the ampoule testing. The vaccine location in each of these ampoules indicates if there was any incidence in the cold chain during transport or storage.

In case of defrost of the vaccine, the volume inside the ampoules is thawed and comes down to the head of the ampoule. As a consequence, no vaccine will be found in the bottom of the upside-down ampoules and all the vaccine will be located in the head of the ampoule. This would mean the vaccine integrity is compromised.

Note that small droplets or little ring of vaccine can be found in the head of the upside-down ampoule, but this is not related to vaccine integrity preservation.

If the result of these three control points is non-conformant or there is any doubt, keep the Dewar in quarantine and inform your provider for further investigation.

Ceva’s Linilog (Liquid Nitrogen Logistics) services

In 2010, Ceva created the Linilog (liquid nitrogen logistics) service with 2 priorities: vaccine integrity and people safety. 175 Ceva hatchery specialists around the world are available to guide the hatchery personnel and monitor their liquid nitrogen handling techniques during their regular visits. They provide Personal Protective Equipment, training and recommendations on the Dewar storage area and handling. Do not hesitate to contact them if you have any questions.

In 2020, Ceva created the Linilog Quality Code of Practice and received the Quality Recognition from an international third-party control body.

The Quality Recognition is now be monitored by Bureau Veritas Group at the country level for each candidate country.

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