Frequently Asked Questions – Serum

What is the shelf life of FBS?

Bovogen Biologicals Sterile Foetal Bovine Serum (SFBS) has a shelf life of 5 years, commencing from the date of manufacture.  We state the expiry date on our product label. Our product Certificate of Analysis states both the Date of Manufacture and the Expiry Date.


A Certificate of Analysis is available on request for all our product batches.

What does raw material 'Country of Origin' mean?

The country of origin of the raw material refers to the country from which the blood was collected (sourced) and converted to raw serum (also called unrefined serum or semi-processed serum).  Our SFBS product label states the country of origin. This means the country from which the raw material was sourced.


Contact us to discuss the detail of our unique traceability supply chain and product traceability guarantee.

What does FBS 'Country of Manufacture' mean?

The country of manufacture is the country where the FBS was sterile filtered to the final finished product.  For example, “Country of Manufacture in Australia” means the SFBS was sterile filtered and bottled to finished product in Australia.


Country of Origin and Country of Manufacture can be different.  For example, SFBS may state the Country of Origin; New Zealand and Country of Manufacture; Australia. This means the raw material was collected / processed in New Zealand and the final sterile filtration occurred in Australia.

What does FBS 'traceability' mean?

There are many variances to how traceability is defined by suppliers.  Bovogen traceability is very clear for each origin of FBS it supplies to the global market.  Our Certificate of Origin states the country from which the raw material was sourced.  A Certificate of Origin is available on request for every product batch we manufacture.


The raw material Country of Origin is important for insights into the countries’ animal health and disease status, as recognised by the World Organisation of Animal Health (OIE). Australia and New Zealand are amongst the highest rated countries for freedom from certain animal diseases, and FBS sourced from Australia or New Zealand is often regarded as a premium product for this reason.


If traceability and sourcing provenance are important to your quality control and quality assurance requirements, it is recommended you discuss this with your supplier.

How to thaw your FBS?

We recommend thawing FBS overnight at a temperature range between 2°C to 8°C.  This is the most suitable method to minimise any degradation. Slowly warm the material at room temperature prior to use to help homogenise the FBS.

Thawing FBS at a laboratory temperature of between 20°C to 25°C is an alternative method.  It is recommended that when thawing FBS at higher temperatures in this range, the product is periodically gently agitated to re-suspend the contents and to ensure the FBS retains a homogenous state.


If the use of an incubator water-bath is your required protocol, we recommend it has temperature control and water circulation capability.  The water temperature should be between 30°C to 35°C (See Note 1 below).  Centre the bottle and ensure the waterline is at the level of the serum. If required secure the bottle to avoid tipping. Gently agitate the serum every 15 minutes until the FBS has thawed.


Note 1. Temperatures above 37°C may have a degradative effect on the serum nutrient components and may compromise optimal serum performance.


Note 2. Sometimes, after thawing the serum, there may be some visible precipitate.  This will not affect the performance of the serum.


Once the serum is completely thawed, place it into a refrigerator until required.

What does sterile filtration mean?

Under quality controlled aseptic conditions, Bovogen passes raw FBS through a sequence of membrane filters with decreasing pore size, finishing with three sequential 0.1-micron absolute filters. The sterile filtered serum is gently circulated in a sterile homogenising bladder prior to bottling to ensure complete homogeneity of every commercial batch. Maintaining aseptic conditions, the homogenised serum is bottled, capped, labelled, neck-sealed and immediately blast frozen to -20°C.


All Bovogen FBS is triple 0.1-micron filtered in a single-use manufacturing system.

What does Single Use System mean?

Single-use systems (SUS) refers to biopharmaceutical manufacturing (bioprocessing) equipment designed to be used once (or for a single manufacturing campaign) and then discarded 1.  Generally, SUS equipment is composed primarily of plastic components that have been sealed and sterilized using gamma irradiation. The primary benefits of SUS versus classic stainless steel (or glass, less frequently used in bioprocessing) is that the equipment comes sterile, which eliminates the need for cleaning, sterilization and validation prior to usage 2.


Single-use or disposable bioprocessing equipment is now used for ≥85% of pre-commercial scale production and is increasingly being adopted for the commercial scale manufacture of biopharmaceutical products.


  1. Langer, E.S., et al, 15th Annual Report and Survey of Biopharmaceutical Manufacturing Capacity and Production, BioPlan Associates, 511 pages, April 2018 (see
  2. Langer E.S. and Radar R.A., Biopharmaceutical Manufacturing is Shifting to Single-Use Systems. Are the Dinosaurs, the Large Stainless Steel Facilities, Becoming Extinct?, , American Pharmaceutical Review 2018

What is Complement?

The serum complement system is a series of dissolved proteins that augment the opsonization of bacteria by antibodies, and allow these antibodies to inactivate pathogens. Some cell culture applications may require the  inactivation of the serum complement within FBS.

What is Heat Inactivation?

The heat-inactivation process is applied to FBS to inactivate the serum complement. It is often recommended in protocols with immunological applications, and with culture of embryonic stem cells, insect cells and smooth muscle cells.


The heat inactivation process must be performed carefully to ensure that only the complement proteins are denatured, and that the desirable serum proteins remain viable in support of cell and tissue propagation. Heating serum for prolonged periods of time can impair, or destroy, desirable protein components and other growth factors, and must be avoided.

How do you Heat Inactivate FBS?

Heat inactivation is a controlled process where the FBS is heated to 56°C and held at that temperature for a period of 30 minutes.


Some laboratories heat-inactivate their FBS based on historical protocol.  It should not be assumed that heat-inactivation of FBS is always necessary to optimise cell culture performance.  The optimum way to test the necessity for heat-inactivation is to measure the FBS performance in cell culture applications, comparing the same culture media with FBS that has been heat-inactivated against FBS that has not been heat-inactivated.


Bovogen offers heat-inactivation as a service to its customers.

What is the purpose of Gamma Irradiation?

Gamma irradiation is the most common post-manufacturing intervention for inactivating viruses in FBS.  Sterile filtration will ensure FBS is free of bacteria, and a range of other micro-organisms. Gamma irradiation is used to eliminate viruses which may remain after filtration.  Gamma Irradiated FBS meets the most stringent sterility requirements of industry, including vaccine and biopharmaceutical production.


Sterile filtered FBS is exposed to ionizing radiation (emanating from a Cobalt-60 source) at a dose between 25kGy and 50kGy. The minimum and maximum irradiation dosages are often determined or specified by customers’ needs or geographic market entry requirements

What is the flocculation that may occur in FBS?

Flocculant that may sometimes be observed in FBS after thawing is usually caused by fibrinogen or fibrin.  These are proteins that occur naturally in FBS and are understood not to affect the performance.

What causes the turbidity in FBS?

Turbidity sometimes observed in FBS can occur after repetitive freeze-thaw cycles, long term storage or heat inactivation.  The turbidity is mostly attributed to serum lipoproteins, which are understood not to affect the performance of FBS.  After long periods of incubation of serum at 37°C, calcium phosphate precipitate may occasionally cause some turbidity. Similarly this is understood not to affect the performance of FBS.