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Heat Inactivation

Heat Inactivation

Heat-inactivated (HI) Fetal Bovine Serum (FBS) is one of the highest-quality serum products...

FAQs

This is a list of commonly asked questions and technical information about Fetal Bovine Serum (FBS) and various Sera. If you have further questions, please contact us. We are happy to assist and discuss this further.

Why is Traceability Important?

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 purchase was made respecting regulations at each level. This unbroken chain of information means complete transparency and entire compliance for all levels of research and settings.

How Does SeraPrime Guarantee Traceability?

SeraPrime works directly with manufacturers who have implemented supply chain controls from harvesting the raw material to filling sterile bottles.

These rigorous traceability controls guarantee complete product traceability, from raw material to the finished product. This enables SeraPrime to determine batch lineage and global traceability.

How Relevant is the Country-of-Origin?

High-quality serum can originate from any country if it is collected, imported, and processed following all the applicable regulatory and industry requirements. There is not one continent or country that produces FBS that has an inherent advantage, in terms of quality, over other origins.

How is the Origin of Serum Determined?

For raw serum, the country of origin is where the serum was collected. For finished serum, the country of origin is where the serum was last processed.

Are Some Origins Better Quality Than Others?

The serum’s origin does not influence cell growth. Regardless of the country of origin, 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. SeraPrime reports on the most extensive analysis of biochemical parameters and testing on cell lines in the industry, making available the results on the Certificates of Analysis.

Why Does Price Differ From Countries/Origins?

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.

What Does USDA Approved Mean?

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.

How Long Can The Serum be Stored Between +2 to +8℃?

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

What is the Recommended Storage Temperature for the Serum?

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.

What is the Best Way to Thaw Serum?

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 the 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.

What Are The Precipitates in the Serum?

Turbidity and flocculent material may be present after thawing or after prolonged freezing and/or refrigeration. Our experience indicates 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 phosphorus. To the best of our knowledge, this does not alter the performance of the serum in cell cultures.

Is it Necessary to Heat Inactivate Serum?

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.

What About Bovine Viruses?

Some cattle viruses can cross the placenta of the cow and infect the calf fetus, thus contaminating FBS and potentially making it unsuitable for use in cell culture. Some of these cattle viruses have a limited distribution and only exist in certain parts of the world.

These are viruses of concern when importing FBS from infected countries. Other cattle viruses exist in all countries, and regardless of country of origin, the FBS must be tested or treated to assure freedom from these and other viruses (See USDA 9 CFR 113.53 and EMEA-CPMP-BWP-1793-02). The treatment of choice for most FBS is gamma irradiation at 25-45 kGy to guarantee freedom from viruses.

What is Endotoxin?

Endotoxin is lipopolysaccharide found in gram negative bacteria’s outer cell membrane. Endotoxin is measured in “Endotoxin Units” per mL (EU/mL).

Suggested industry standard is < 10 EU/mL, some manufacturers will advertise that the lowest levels are “better” for cell growth and justify a higher serum cost. If your application does not have endotoxin requirements, then the use of a “Standard Grade” with slightly elevated levels will offer savings and the same quality/performance.

What is Hemoglobin?

Hemoglobin is from lyses of red blood cells during the transportation and processing of raw blood into serum. No reported effects are related to hemoglobin concentrations of < 100 mg/dL. Typical levels of hemoglobin in serum range from 10-30 mg/dL.

Are SeraPrime Products Sterile?

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

Foot and Mouth Disease (FMD): Does it Matter?

FMD is relevant for regulatory import purposes but not for cell growth. The USA and a few other countries only allow FBS imports from countries free from FMD, WITHOUT vaccination, while most other countries also accept FMD-free WITH vaccination. Both types of FMD-free countries are free of FMD outbreaks and circulating FMD viruses, as verified by the OIE and declared equally safe.

What is BSE?

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

What is the Risk of BSE in Serum Products?

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. 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.

What Are the Sampling Rules for Sterility Tests on Sera?

The sampling for sterility tests of all SeraPrime’s products conforms to the European Pharmacopeia requirements.

How Are the Samples Tested for Viruses?

The serum is tested for the viruses (BVD, IBR, P13) by using a cell culture method, so that live viruses, if present, are detected in the serum.

Why is FBS Sometimes Gamma Irradiated?

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

Does Gamma Irradiation Affect FBS Performance?

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 breaks some proteins and decolorate the product by reducing hemoglobin 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.

SeraPrime suggests you test your cell lines with gamma irradiated serum to define the potential impact of the treatment on your applications.

Product Specs & Certificates

Access detailed specifications, Certificates of Analysis (CoAs), and documentation for SeraPrime’s full range of serum products.

Certificate of Analysis (Example)