Beef Extract, Desiccated

Intended Use

Beef Extract Powder, Bacto Beef Extract, Desiccated and Beef Extract (paste) are used in preparing microbiological culture media.

Summary and Explanation

Beef Extract is intended to replace aqueous infusion of meat in microbiological culture media. Beef Extract is frequently used at a concentration of 0.3 to 1.0% in culture media, although concentrations may vary depending on the nutritional requirements for the medium formulation. Beef Extract may be relied upon for biochemical studies, particularly fermentation reactions, because of its independence from fermentable substances that would interfere with the accuracy of such determinations.
Beef Extract was used in media for early studies of nonsporulating anaerobes of the intestinal tract and as a stock broth in the study of nutritional needs of streptococci. Prokofeva et al.¹ used Beef Extract for growing thermoacidophilic organisms newly isolated from hot springs in Kamchatka, Russia. Kataoka and Tokiwa² used Beef Extract as a nitrogen source in studies of mannose production by Clostridium tertium strains isolated from soil and methanogenic sludge. In addition, Beef Extract is a nutritive ingredient in many classical culture media, including Antibiotic Assay media described in The United States Pharmacopeia,³ and several media recommended for standard methods applications.^4-6
Beef Extract Powder is a meat extract dried to a powdered form. Bacto Beef Extract, Desiccated is the dried form of Beef Extract (paste) and was developed to provide a product for ease of use in handling.
Beef Extract is a meat extract in paste form.
These products are to be used in a one for one substitution; however, variations tend to be formulation-specific and require actual performance testing.

Principles of the Procedure

Beef Extract Powder, Bacto Beef Extract, Desiccated and Beef Extract (paste) are derived from infusion of beef and provide an undefined source of nutrients. These Beef Extract products are not exposed to the harsh treatment used for protein hydrolysis, so they can provide some of the nutrients lost during peptone manufacture.⁷ Beef Extract Powder, Bacto Beef Extract, Desiccated and Beef Extract (paste) are mixtures of peptides and amino acids, nucleotide fractions, organic acids, minerals and some vitamins. The function of these Beef Extract products can be described as complementing the nutritive properties of peptone by contributing minerals, phosphates, energy sources and those essential factors missing from peptone.⁸

User Quality Control

Identity Specifications
Beef Extract, Desiccated
Dehydrated Appearance: Medium to dark brown crystalline powder.
Solution:                        0.3% solution, soluble in purified water upon
                                     warming. Solution is light to medium amber, clear.
Reaction of 0.3%
Solution at 25°C:            pH 7.0 ± 0.4
Cultural Response
Beef Extract, Desiccated
Prepare a sterile solution of 0.3% Beef Extract, Desiccated and 0.5% Bacto Peptone. Adjust final pH to 6.9-7.1. Inoculate and incubate tubes at 35 ± 2°C for 18-48 hours.

Typical Analysis

Refer to Product Tables in the Reference Guide section of this manual.

Directions for Preparation from Dehydrated Product

Refer to the final concentration of Beef Extract Powder, Beef Extract, Desiccated or Beef Extract in the formula of the medium being prepared. Add appropriate product as required.

Procedure

See appropriate references for specific procedures using Beef Extract Powder, Bacto Beef Extract, Desiccated or Beef Extract.

Expected Results

Refer to appropriate references and procedures for results.

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