about Frequently Asked Questions

Below, is a list of commonly asked questions, contact us if you don't find the answer

With more than 35 years of experience with serum as its main activity, Biowest is dedicated to quality and service, to vertical integration, and to providing a wide range of origins.

Biowest takes full responsibility of ensuring a vertically integrated supply chain to the highest standard of quality, traceability and safety.

In 2004, Biowest was acquired by the Viking/Serascandia group to become the first vertically integrated serum company. In the same year, Biowest denounced cases of misrepresentation to the authorities and informed the affected victims, highlighting the importance of serum industry traceability guidelines and oversight, and promoting the creation of the ISIA and ESPA.

ISIA is the International Serum Industry Association.
Its main objective is to establish traceability guidelines and harmonize international import rules, working with government and international authorities.

ESPA is the European Serum Products Association (ESPA).
Its purpose is to promote the use of serum, the harmonization of regulations, connect companies of the serum processing industry in the EU and Non-EU countries, and represent their interests.

Biowest FBS Premium has been especially selected to guarantee high performances and low batch to batch variations. You can save time by purchasing pretested FBS (See Catalogue Number S181B).

The choice of the sera supplier is based on Quality, Traceability and Safety, endorsed by comprehensive documentation, backed up by audits of the supply chain back to the serum source, and covering several years.

In addition to normal testing, Biowest also tests FBS for stem cell work suitability. However, it is recommended that batches used for stem cells should be tested on specific cell lines for the specific conditions required.

Dr Yamanaka, in his Nobel Prize winning work related to stem cell research, selected Biowest FBS after testing our batches.

Serum is thawed at 2-8°C to prevent degradation; alternatively, it may be thawed at room temperature with periodic agitation to resuspend the contents.

Thawed serum should be mixed thoroughly before being added to cell culture medium.

Temperatures above 37°C can compromise serum performance by accelerating the degradation of critical serum factors, and should be avoided in the lab.

Turbidity and flocculent material may be present after thawing or after prolonged freezing and/or refrigeration. Our experience indicates that these modifications do not affect the biological performance of the serum.

Some of the precipitates are due to fibrin:
Our collection procedures and rapid freezing may leave some fibrinogen in the serum.
Fibrinogen is the soluble precursor of the clot-forming protein, fibrin. The fibrin may appear after thawing or heat inactivation. Fibrin does not alter the capacity of the serum to promote cell growth.

It is recommended to use the serum without treatment (filtration or centrifugation).

Some of the precipitates are due to Calcium Phosphate:
Serum that is incubated at 37°C for extended periods will become cloudy and deposits may appear. They are composed of calcium and phosphorous.
To the best of our knowledge, this does not alter the performance of the serum in cell cultures.

For most cell culture applications, heat inactivation of serum is not recommended. Heat inactivation degrades complement proteins that may interfere with immunological assays.
Heating serum for prolonged periods of time can reduce or destroy growth factors, as well as increase the formation of deposits which are commonly mistaken for microbial contamination.

Start by thawing the serum and the control serum bottle at 2-8°C.
Stir the bottled serum to avoid a precipitant from forming during the thawing, then place it in the water bath adjusted to 80°C.

Once the control bottle temperature reaches 50°C, adjust the bath thermostat to 70°C; when the bottle temperature reaches 55°C, change the thermostat to 60°C.

When the serum reaches the temperature of 56°C, use a timer (30 minutes is the registered time) and change the thermostat of the water bath to 56°C. During those 30 minutes, check the temperature regularly and maintain it stable by adjusting the thermostat, by adding some cold water, and by lowering the lid or not. Stir the serum every 5 to 10 minutes.

Keep the serum at room temperature for 30 minutes, and then freeze the serum at -20°C.

Note :
The stirring is crucial for good serum quality. If the serum is not correctly mixed, a precipitant of salts, proteins and lipids will appear, and allow crystalline and flocculation deposits to form. These deposits are not toxic for cell culture but affect the serums appearance and consistency. Heating the serum for long periods can destroy the growth promoters, which can also enable deposits to form.

Serum may be stored between +2 to +8°C for up to 8 weeks without diminishing its performance (*).

Internal studies in Biowest have shown that during 26 weeks of storage (between +2 and +8°C) the serum’s capacity to promote cell growth was not significantly altered.

(*) Art to Science, Vol.19, No.2, “Serum Stability at Refrigerated Temperatures (2-8°C).

The serum should be stored frozen and protected from light.
The recommended storage temperature is -10°C to -40°C.

At temperatures below -40°C, the bottles may become brittle increasing the risk of breakage

Some preparations of trypsin contain phenol red. Since the product is shipped with dry ice, there could be a significant CO2 build up in packaging.

This CO2 may enter the solution and lower the pH slightly, giving an orange (around pH 6.5) vs. pinkish (around 7.3) color. The solution, if orange (acidic) can still be good to use as it is, or sodium hydroxide may be added to adjust the pH.

Tetracyclines are a family of broadspectrum antibiotics that inhibits bacterial protein synthesis by blocking binding of aminoacyl-tRNA to the ribosome. Due to growing concerns surrounding development of antibiotic resistant microbes, the use of tetracycline as a growth promoter was banned in EU in the early 1970s.

However, in the rest of the world tetracycline is still among the most frequently used antibiotics in livestocks.

Since 1992, the Tetracycline-controlled Transcriptional Activation system, or “Tet-Off” and “Tet-On” systems as they are often referred to, has been used for induction of mammalian expression in cell-line models used across laboratories worldwide. In the Tet-Off system, gene expression is silenced if tetracycline is present and induction of expression is done by removal of tetracycline from the media.
Vice versa, in the Tet-On system, gene expression is silenced in the absence of tetracycline and induced by addition of tetracycline to the cell culture media.

Both systems are very sensitive to even small amount tetracycline found in FBS. As such, if a researcher uses these tools to control gene expression in his cell-culture models, it’s very important to have a supply of FBS that is completely free of tetracycline.

Please feel free to contact your Biowest representative for further information or guidance in selecting the best suitable batch for your tetracycline sensitive application.

Human serum from type AB donors is deficient in antibodies against the A and B blood-type antigens. It therefore minimizes immunoreactivity since most human serum users work on cells from the immune system.

Women who have been pregnant may develop antibodies against major histocompatibility class (MHC) antigens carried on the father’s cells and/or the foetus’ cells.

Male donors present no such risks.

There is a wide range of applications for fetal bovine serum. The most important is in the field of biopharmaceuticals and vaccines. It is used in the research, manufacture and control of human and veterinary vaccines and of drugs, many of which are at the cutting edge of drug development.

Fetal bovine serum is also used extensively in research.

FBS is collected from the fetuses of pregnant cows, slaughtered in compliance with the OIE (World Animal Health Organization) guidelines and internationally accepted standards of veterinary inspection.

The OIE (World Organization for Animal Health) is an intergovernmental organization created in 1924. In 2011, the OIE totaled 178 member countries and territories.

Its missions are :
– to ensure transparency in the global animal disease situation
– to collect, analyze and disseminate veterinary scientific information
– to provide expertise and encourage international solidarity in the control of animal diseases
– to safeguard world trade by publishing health standards for international trade in animals and animal products
– to improve the legal framework and resources of National Veterinary Services Organization

FBS is essentially a natural product.

All FBS batches are unique, with specific characteristics, different from all other batches.

The availability of FBS is diminishing.

Meat and calf prices are increasing as consumers in some countries increase the consumption of beef, and as cattle breeding techniques are permanently improving.

These combined factors lead to a reduced frequency of pregnant cows at slaughter. The collection of FBS in new countries has, for many years, compensated for the decrease in supply, but now there are no more new producer countries available.

The present world supply of FBS is short and will continue decreasing.

The serum’s origin has no influence on cell growth. Biowest has compared cell growth in FBS from seven different countries of three continents, and confirmed that regardless of the country of origin, all cell lines tested had the same average performance.

One batch of FBS may work well for one specific cell line, but not for another. “Serum quality” is specific for each cell line. That is why testing of FBS is widely used when dealing with sensitive cell lines. Biowest performs the most extensive analysis of biochemical parameters and testing on cell lines in the industry, making available the results on the Certificates of Analysis

A huge price difference exists between countries classified as “FMD-Free-without-vaccination” for which demand exceeds supply, and countries listed as “FMD-Free-with-vaccination” where supply historically has exceeded demand.

The price difference has been several hundred per cent, whereby serum users in the US have paid billions of USD more than serum users in the EU. Proposals from USDA to harmonize US and EU import rules for FBS relating to FMD (following OIE guidelines), have repeatedly been turned down by the US serum industry.

The serum’s source is from a USDA Approved country. This means that serum is produced from blood collected in countries that have been approved by the United States Department of Agriculture (USDA) to export ruminant serum products to the United States.

Eligible countries that export fetal bovine serum into the U.S. include: Australia, Canada, Chile, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, New Zealand, Nicaragua, and Panama.

The demand for FBS is growing along with the latest research developments, including stem cells, cell therapy, new vaccines and proteomics.

Australian FBS prices are higher because Australia is perceived to be a “safer” origin for BSE and cattle viruses.

Canada and Australia were the first countries outside the USA where FBS was produced. In the 1980s, BSE cases that occurred in North America became a strong argument in favor of Australian FBS.

The point was made that being “isolated”, Australia was necessarily the most secure origin.

FBS Imports into the EU are less restricted than in the USA. A proposal made by USDA in 1994 to apply the same FBS import policies as the EU did not get support from the US FBS industry.

The International Serum Industry Association (ISIA) supports efforts to harmonize import rules, suggesting compliance with the OIE recommendations. In the meantime, FBS in the USA remains more than twice as expensive as in Europe.

Maintaining cells in vitro in a healthy condition and over time is a complex task. They will only survive, grow and multiply if they are well fed and provided with an appropriate and protective environment. Complex mixtures of substances (“media”) are used to bathe the cells in order to both feed and protect them.

Different cells have different requirements. In many instances the presence of serum in the mixture is essential if the cells are to grow adequately and normally.

Serum is the centrifuged fluid component extracted from either clotted or defibrinated whole blood. Bovine serum comes from blood taken from domestic cattle.Whilst the procedure of making serum may seem to be straightforward, the processing of serum takes place under very tightly controlled conditions.

The process has been carefully developed and uses sophisticated facilities and equipment, and is accompanied by extensive testing particularly stringent when processed bovine serum is intended for use in the production of medicinal products.

Fetal Bovine Serum (FBS) comes from the blood drawn from a bovine fetus via a closed system of collection at the slaughterhouse.

Fetal Bovine serum is the most widely used serum supplement for the in vitro cell growth factors because of its high content of embryonic growth promoting factors.


Bovine serum is a by-product of the meat industry. Bovine blood may be taken at the time of slaughter, from adult cattle, calves, very young calves or (when cows that are slaughtered are subsequently found to be pregnant) from bovine fetuses.

It is also obtained from what are called “donor” animals which give blood more than once.

Traceability is important because it provides a chain of identity of the product from the country and slaughterhouse of origin, to the processing, packaging and labeling facilities ready for sale and final distribution.

As you can verify, traceability ensures that the product you buy was made respecting regulations at each level. This unbroken chain of information means complete transparency and entire compliance.

Biowest completely controls the supply chain from collecting the raw material to filling sterile bottles.

Our traceability with SAP management software SAP S/4HANA guarantees complete product traceability, from raw material until the end product. This software program plays a key role for achieving complete supply network traceability – enabling Biowest to determine batch lineage and global traceability.

High quality serum can originate from any country, as long as it is collected, imported, and processed following all the applicable regulatory and industry requirements.
No one continent or country which produces FBS has an inherent advantage, in terms of quality, over other origins.

Since the 1990s, from time to time, cases of illegal practices have been rumored. Only two cases are known to have been reported to authorities.

In 2004, Biowest realized we had purchased and resold misrepresented origins; in 2013, GE realized it had sold misrepresented and adulterated FBS products, after acquiring the company PAA with activities in Austria, Canada and Australia.

In both cases affected victims were informed, and product was recalled. Other cases are known to be under investigation. These cases illustrate the importance of having complete control of the supply chain.

“Adulteration” is the most damaging of the criminal activities that may affect serum users!

FBS can be adulterated by the addition of water, growth factors and/or serum of other species. Unscrupulous companies in order to enhance performance and/or lower the cost of the product can carry out one or more of these or similar activities.
These practices are extremely serious as they affect critical results of life science research, and the purity of final products obtained in biopharmaceuticals, diagnostics, or vaccines.

When such cases are detected, victims having used adulterated product must be informed to make it possible to evaluate the damage and take corrective actions.

“Misrepresentation” is when the product is mislabeled in terms of the declared origin, and can be total or partial:

– “Total” is when FBS from a less expensive origin is sold as if it were from a more expensive origin;
– “Partial” is when a less expensive origin and a more expensive origin are mixed e.g. in proportion 49-51, and only the more expensive 51%- origin is declared. This generates an illicit profit for seller, at the expense of the serum users; and may cause companies to unknowingly violate import regulations or product master files.

The actual research results and end products are unlikely to be seriously affected, but falsified origins violate government, industry and consumer standards of honesty and traceability.

“Smuggling” is a way of misrepresentation, and can be in the form of importing a product under a false description; directly to a final destination, or via third country.

OIE’s guidelines for animal welfare are respected in the countries where the FBS is collected (OIE Terrestrial Code 7.5 Slaughter of Animals).

See EFSA – Animal welfare

There are some cell lines specific serum-free alternatives available, including Biowest FreeAdd (S6010).

In most cases, cell adaptation is needed, yields are lower and costs are higher.

The slaughtering of pregnant animals is, in most cases, an unplanned event. The frequency depends on farming techniques. In most cases, the condition of gestation is unknown. In the case of cattle moving freely around with heifers and steers together.

No cows are killed with the main purpose of harvesting the fetal blood. The blood is collected as a by-product from cattle slaughter operations for the bovine meat. The pregnancy condition is unknown when an animal enters the slaughtering line. The percentage of pregnant cows going to slaughter is very low and decreasing year by year as cattle farming techniques constantly improve.

The collection of the blood is done without causing pain to the fetus. The fetus’s life ends through oxygen depletion, generally agreed to be a gentle method of life termination.

Cell culture technology can reduce the use of live animals in science. Research is also being done to produce meat by cell culture, which could ultimately lead to the end of breeding animals for food.

Except where notified on product labels, Biowest sera and liquid media are sterile filtered. Sterility is not guaranteed after opening. The use of aseptic manipulation techniques is recommended.

FMD is relevant for regulatory import purposes, but not for cell growth. The United States and a few other countries only allow imports of FBS from FMD-free countries WITHOUT vaccination, while most other countries accept FMD-free countries WITH vaccination.

Countries free of FMD outbreaks and circulating FMD viruses, as verified by the OIE, are also declared safe.

Bovine spongiform encephalopathy (BSE), more commonly known as “mad cow” disease, is a fatal neurodegenerative disease (encephalopathy) in cattle.

According to the OIE (World Animal Health Organization), there is no risk of BSE being transmitted in several products, including: milk, hides and skins, deboned meat, blood and blood by-products, such as fetal bovine serum (OIE Terrestrial Code 11.4 BSE). Most OIE member countries have adopted this position, including the European Union and the United States (USDA).

For some time, BSE was an argument used in favor of certain origins. After the OIE has determined that BSE is not transmitted by blood products, these arguments have become obsolete.

The sampling for sterility tests of all Biowest products conforms to the European Pharmacopeia requirements.

Biowest tests the serum for the viruses (BVD, IBR, PI3) by using a cell culture method, so that live viruses, if present, are detected in the serum.

FBS is sometimes gamma irradiated to eliminate all potential virus risks.

At standard dosage of gamma irradiation, no loss of performance is observed on the first generations of cells. We notice no change on hormones, osmolarity, pH, endotoxins nor electrophoretic profile of the FBS. As ionizing radiations kill viruses, it also break some proteins and decolorate the product by reducing haemoglobin level.

Radiations also decrease the serum metabolites (ALP, ALT, AST, LDH) and may slightly affect growth promotion, plating efficiency and cloning efficiency with some cell lines.
Biowest suggests you testing your cell lines with gamma irradiated serum in order to define the potential impact of the treatment on your applications.

If viruses seem to modify the results of your work, Biowest also proposes you test FBS Biopharm, our highest quality, certified free of 11 major cattle viruses.

A simple PCR test will detect DNA and RNA from both alive and dead viruses. PCR testing must be combined with cell cultures tests to detect live viruses.