Microbiology

• Oxoid AFPA Medium Base is a selective identification medium for the detection of Aspergillus flavus and Aspergillus parasiticus.
• Also available: Membrane Clostridium Perfringens Selective Supplement, Part No. SR0188E.

AFPA Medium Base, Oxoid Composition

AFPA Medium Base, Oxoid Preparation:

Suspend 22.75g in 500ml (45.5g/l) of distilled water and heat to dissolve completely. Reconstitute one vial SR0078E per 500ml medium or one vial SR0078H per 2 litres medium, as directed. Add the vial contents to the AFPA Base. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C. Mix well and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.

• Oxoid Dichloran-Glycerol (DG18) Agar Base is a selective low water activity (aw) medium for xerophilic molds from dried and semi-dried foods.
• Also available Chloramphenicol Selective Supplement, Part No. SR0078E and Chloramphenicol Selective Supplement, Part No. SR0078H.

Dichloran-Glycerol (DG18) Agar Base, Oxoid Composition

Dichloran-Glycerol (DG18) Agar, Oxoid Preparation:
Suspend 15.75g in 500ml (31.5g/l) of distilled water and heat to dissolve completely. Add 110g per 500ml (220g/l) of Glycerol (Analytical Reagent grade). Reconstitute one vial SR0078E per 500ml medium or one vial SR0078H per 2 litres medium, as directed. Add the vial contents to the DG18 Agar Base. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C, mix well and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.

Precautions
The dichloran compound used in this medium is Botran® 2,6-Dichloro-4-Nitro-Analine (CAS: 99-30-9).

• Oxoid DRBC Agar Base (Dichloran Rose-Bengal Chloramphenicol Agar Base) is a selective medium for yeast and molds associated with food spoilage.
• Also available Chloramphenicol Selective Supplement, Part No. SR0078E and Chloramphenicol Selective Supplement, Part No. SR0078H

DRBC Agar Base, Oxoid Composition

DRBC Agar, Oxoid Preparation:
Suspend 15.75g in 500ml (31.5g/l) of distilled water and heat to dissolve completely. Reconstitute one vial SR0078E per 500ml medium or one vial SR0078H per 2 litres medium, as directed. Add the vial contents to the DRBC Agar Base. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C, mix well and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates of medium at 2-8°C.

Precautions
ROSE-BENGAL PHOTO-OXIDIZES TO FORM TOXIC COMPOUNDS. STORE PLATES OF THE MEDIUM IN THE DARK AND AVOID EXPOSURE TO LIGHT.
Some strains of fungi may be inhibited on this medium.
The dichloran compound used in this medium is Botran® 2,6-Dichloro-4-Nitro-Analine (CAS: 99-30-9).

• Oxoid K-F Streptococcus Agar is a selective medium for the isolation and enumeration of Group D Streptococci.
• Also available TTC Solution, Part No. SR0148A.

K-F Streptococcus Agar Base, Oxoid Composition

K-F Streptococcus Agar, Oxoid Preparation:
Suspend 38.2g in 500ml of distilled water. Bring to the boil with frequent agitation. Boil for 5 minutes. Cool to 50°C and add aseptically 1 vial (5ml) of 1% 2,3,5-Triphenyltetrazolium chloride (SR0229K). Pour into sterile Petri dishes when using the membrane filtration method or hold at 45°C when using the pour-plate method.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.

Precautions
Observe the HAZARD precautions regarding sodium azide when disposing of the medium. The pH of the medium should not fall below 7.0 as it may become inhibitory towards enterococci. KF Streptococcus Agar is not specific for the presumptive identification of Group D streptococci. Further tests must be made to confirm the identity of the organisms isolated.

Enrich and improve the isolation of salmonellae from feces and food samples with Thermo Scientific™ Oxoid™ Selenite Cystine Broth Base. This modified medium is based upon the formulation described by Leifson with added cystine.

Selenite Cystine Broth Base, Oxoid Composition

Selenite Cystine Broth, Oxoid Preparation:
Dissolve 4g of sodium biselenite LP0121 in 1 litre of distilled water and then add 19g of Selenite Cystine Broth Base. Warm to dissolve and dispense into containers. Sterilise by placing in free flowing steam for 15 minutes. DO NOT AUTOCLAVE.

Robertson reported miscarriages and possible tetragenic effects on pregnant laboratory workers which may have been caused by the ingestion of sodium biselenite. To minimise any possible risk of teratogenicity to laboratory workers the sodium biselenite is not included in the dry powder but should be prepared separately as a solution to which the Selenite Cystine Broth Base is added.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C away from light.

Precautions
Observe the precautionary comments made about sodium biselenite in Selenite Broth Base CM0395.
Discard the prepared medium if large amounts of reduced selenite can be seen as a red precipitate in the bottom of the bottle.
Do not incubate longer than 24 hours because the inhibitory effect of selenite is reduced after 6-12 hours incubation.
Take subcultures of broth from the upper third of the broth column which should be at least 5 cm in depth.

• Oxoid Campylobacter Agar Base is used for the isolation of Campylobacter jejuni and Campylobacter coli from human, animal, avian and environmental specimens.
• Also available Campylobacter Selective Supplement (Blaser-Wang), Part No. SR0098E NMKL; Bolton Broth Selective Supplement, Part No. SR0183E; Modified Bolton Broth Selective Supplement, Part No. SR0208E; Modified Preston Campylobacter Selective Supplement, Part No. SR0204E; and Campylobacter Selective Supplement Preston, Part No. SR0117E.

Campylobacter Agar Base, Oxoid Composition

Preston Campylobacter Selective Agar, Oxoid Preparation:
Suspend 18.5g of Campylobacter Agar Base in 475ml of distilled water and bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C. Aseptically add 25ml of Lysed Horse Blood (SR0048), and 1 vial of Preston Campylobacter Selective Supplement (SR0117 or SR0204) reconstituted as directed and one vial of Campylobacter Growth Supplement (SR0232). Mix well and pour into sterile Petri dishes.

Preston Campylobacter Selective Enrichment Broth, Oxoid Preparation:
Dissolve 12.5g of Nutrient Broth No.2 (CM0067) in 475ml of distilled water and sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C or below. Aseptically add 25ml of Lysed Horse Blood (SR0048), 1 vial of Preston Campylobacter Selective Supplement (SR0117 or SR0204) and 1 vial of Campylobacter Growth Supplement (SR0232). Aseptically dispense 5ml volumes in sterile small screw-capped bottles. The Selective Enrichment Broth may be stored for up to 7 days at 2-8°C.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.

Isolate and enumerate microorganisms in milk and dairy products with Thermo Scientific™ Oxoid™ Milk Plate Count Agar (Dehydrated). Milk Plate Count Agar is equivalent to the medium recommended by British Standard Institution and International Organization for Standardization.

Milk Plate Count Agar (Dehydrated), Oxoid Composition

Milk Plate Count Agar (Dehydrated), Oxoid Preparation:
Suspend 19.5g in 1 litre of distilled water. Bring to the boil with frequent agitation, mix and distribute into final containers. Sterilise by autoclaving at 121°C for 15 minutes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.

Oxoid Tetrathionate Broth is used for the selective enrichment of Salmonella spp.

Tetrathionate Broth, Oxoid Composition

Tetrathionate Broth, Oxoid Preparation:
Suspend 46g in 1 litre of distilled water and bring to the boil. Cool to below 45°C and add 20ml of iodine-iodide solution immediately before use. Mix continuously whilst dispensing 10ml volumes into sterile tubes. Use the complete medium (with added iodine) on the day of preparation.

The base may be prepared beforehand and kept for several weeks at 4°C. Iodine-iodide solution can then be added at the time of use to the quantity of medium needed.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the base broth at 2-8°C. Use the medium immediately after adding the iodine solution.

Selectively enrich Salmonella spp. from food and environmental specimens with Thermo Scientific™ Oxoid™ Rappaport-Vassiliadis Enrichment Broth (Dehydrated). Rappaport-Vassiliadis Enrichment Broth selects for Salmonella species by exploiting their characteristics when compared with other Enterobacteriaceae, such as the ability to survive at relatively high osmotic pressure, multiply at relatively low pH values, be relatively more resistant to malachite green, and have relatively less demanding nutritional requirements.

Rappaport-Vassiliadis Enrichment Broth (Dehydrated), Oxoid Composition

THIS MEDIUM IS VERY HYGROSCOPIC AND MUST BE PROTECTED FROM MOISTURE.
The quantities given for the formula as classically described made 1110ml of medium. They have been published this way in the Oxoid literature to coincide with the scientific literature.

The directions for reconstituting Oxoid Rappaport-Vassiliadis (RV) Enrichment Broth follow usual Oxoid practice and specify the weight needed for 1 litre of medium.

Rappaport-Vassiliadis Enrichment Broth (Dehydrated), Oxoid Preparation:
Add 30g (the equivalent weight of dehydrated medium per litre) to 1 litre of distilled water. Heat gently until dissolved completely. Dispense 10ml volumes into screw-capped bottles or tubes and sterilise by autoclaving at 115°C for 15 minutes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Precautions
RV Broth should not be used if Salmonella typhi is suspected.
Note the difference in weight between the classical formula on the label and the reduced weight per litre, using anhydrous magnesium chloride.

Isolate and enumerate spoilage organisms of citrus products with Thermo Scientific™ Oxoid™ Orange Serum Agar (Dehydrated). Orange Serum Agar is developed specifically for the isolation and enumeration of microorganisms that are capable of surviving citrus products. The low pH of these products limits the growth of microorganisms to those capable of tolerating the acidic environment.

Orange Serum Agar, Oxoid Composition

Orange Serum Agar, Oxoid Preparation:
Suspend 37g in 1 litre of distilled water and bring gently to the boil to dissolve completely. Dispense into final containers and sterilise by autoclaving at 121°C for 15 minutes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Isolate Legionella from environmental samples and clinical specimens using Thermo Scientific™ Oxoid™ Legionella CYE Agar Base when used with Legionella Growth Supplement SR01110. Legionella CYE Agar Base is a non-selective medium that exhibits optimal recovery of legionellaceae in short incubation periods from both environmental samples and clinical specimens.

Legionella CYE Agar Base, Oxoid Composition

BCYE Agar, Oxoid Preparation:
Suspend 2.5g of Legionella CYE Agar Base per 90ml of distilled water and bring gently to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Reconstitute one vial SR0110A per 100ml medium or one vial SR0110C per 500ml medium, as directed. Allow medium to cool to 50°C and aseptically add the vial contents. Mix gently and pour into sterile Petri dishes. The final pH of the medium should be 6.9 ± 0.2.

Storage conditions and Shelf life
Store the dehydrated medium below 30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C away from light.

• Oxoid Yersinia Selective Agar Base (Schiemann’s CIN Agar) is used for the isolation and enumeration of Yersinia enterocolitica from clinical specimens and foods.
• Also available Yersinia Selective Supplement, Part No. SR0109E. Industrial Reference: FDA.

Yersinia Selective Agar Base, Oxoid Composition

Yersinia Selective Agar, Oxoid Preparation:
Suspend 29g in 500ml of distilled water and bring gently to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Allow to cool to approximately 50°C and aseptically add the contents of one vial of Yersinia Selective Supplement SR0109 reconstituted as directed in the instructions for use that accompany the product. Mix gently and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C for not more than 24 hours.

Precautions
Some strains of Yersinia enterocolitica may grow poorly or not at all. Other species of Yersinia may grow along with some enteric organisms. It is therefore essential that full identification tests are carried out on suspect colonies.

**This product is not available at the moment. Please contact us for more information.

Oxoid Universal Beer Agar is used for the isolation of beer spoilage microorganisms.

Universal Beer Agar, Oxoid Composition

Universal Beer Agar, Oxoid Preparation:
Suspend 62g in 750ml of distilled water and bring to the boil to dissolve completely. Add 250ml beer, without degassing, to the hot medium and mix gently. Distribute into final containers and sterilise by autoclaving at 121°C for 10 minutes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Precautions
When handling cycloheximide observe the precautions to be taken under HAZARDS.

Oxoid Vogel-Johnson Agar is used for the detection of Staphylococcus aureus from foods and clinical specimens.

Vogel-Johnson Agar, Oxoid Composition

Vogel-Johnson Agar, Oxoid Preparation:
Suspend 61g in 1 litre of distilled water and bring gently to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and add 5.7ml of sterile 3.5% potassium tellurite solution SR0030 (equivalent to 20ml of 1% potassium tellurite).

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Precautions
All presumptive Staphylococcus aureus colonies should be confirmed with further tests. Do not heat the medium after the addition of potassium tellurite.

Oxoid Nutrient Gelatin is used for the differentiation of microorganisms by their proteolytic effects.

Nutrient Gelatin, Oxoid Composition

Nutrient Gelatin, Oxoid Preparation:
Suspend 128g in 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Mix well before pouring and cool below 20°C or leave to set in a refrigerator.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Precautions
Do not shake the gelatin tubes whilst they are warm because growth and liquefaction of gelatin frequently occurs on the surface layer only.
In routine diagnostic work report gelatin liquefaction or not. The type or shape of liquefaction is of less importance.

Oxoid Rogosa Agar is used for the selective isolation and enumeration of lactobacilli.

Rogosa Agar, Oxoid Composition

Rogosa Agar, Oxoid Preparation:
Suspend 82g in 1 litre of distilled water and bring to the boil to dissolve completely. Add 1.32ml glacial acetic acid and mix thoroughly. Heat to 90-100°C for 2-3 minutes with frequent agitation. Distribute into sterile tubes, Petri dishes or bottles.
DO NOT AUTOCLAVE.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Precautions
Lactobacillus carnis does not grow on this medium.
All colonies must be tested by Gram stain and catalase test before carrying out further identification tests.

Oxoid Wilkins-Chalgren Anaerobe Agar is used for the growth of anaerobes and recommended for antimicrobial susceptibility testing of anaerobes.

Wilkins-Chalgren Anaerobe Agar, Oxoid Composition

Wilkins-Chalgren Anaerobe Agar, Oxoid Preparation:
Suspend 43g in 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates of medium at 2-8°C away from light.

Selectively isolate and enumerate Bacillus cereus from food samples with Thermo Scientific™ Oxoid™ Bacillus cereus Selective Agar Base (Dehydrated). Bacillus cereus Selective Agar Base meets the requirements for a medium that is sufficiently selective to be able to detect small numbers of Bacillus cereus cells and spores in the presence of large numbers of other food contaminants. The medium is also sufficiently diagnostic that colonies of Bacillus cereus are readily identified and confirmed by microscopic examination.

Bacillus cereus Selective Agar Base, Oxoid Composition

Bacillus cereus Selective Agar Base, Oxoid Preparation:
Suspend 20.5g in 475ml of distilled water and bring gently to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and aseptically add the contents of one vial of Polymyxin B Supplement (SR0099) reconstituted as directed, then add 25ml of sterile Egg Yolk Emulsion (SR0047). Mix well and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and Polymixin B Supplement at 2-8°C. Use before the expiry date on the label.
The prepared medium may be stored at 2-8°C.

Precautions
On this medium Bacillus cereus is indistinguishable from Bacillus thuringiensis.
Identify Bacillus cereus by colony form, colour, egg yolk hydrolysis and confirm with cell and spore morphology.
Occasional strains of Bacillus cereus show weak or negative egg yolk reactions.

Identify members of the coliform group of bacteria in food and water samples with Thermo Scientific™ Oxoid™ Minerals Modified Glutamate Medium (Dehydrated). The mineral content of the medium allows for the superior cultivation and enumeration of coliforms.

Minerals Modified Glutamate Medium, Oxoid Composition

Minerals Modified Glutamate Medium, Oxoid Preparation:
Double Strength:
Dissolve 5g of ammonium chloride in 1 litre of distilled water. To this add 22.7g of Minerals Modified Medium Base, and 12.7g of Sodium glutamate LP0124. Mix to dissolve completely. Sterilise by autoclaving for 10 minutes at 116°C; alternatively heat to 100°C for 30 minutes on three successive days.

Single strength:
Dissolve 2.5g of ammonium chloride in 1 litre of distilled water. To this add 11.4g of Minerals Modified Medium Base, and 6.4g of Sodium glutamate LP0124. Mix to dissolve completely. Sterilise by autoclaving for 10 minutes at 116°C; alternatively heat to 100°C for 30 minutes on three successive days.

Note
To improve the stability of the dehydrated medium on storage the sodium glutamate LP0124 is supplied separately and must be added to the basal medium CM0607.

The pH of the final medium is critical for optimum performance and the sterilised broth should be checked to confirm that it is at pH 6.7 before use.

Differences in heating procedures cause differences in final pH value. If necessary the heating procedure should be adjusted so that the final pH, after sterilisation is 6.7

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Precautions
Presumptive positive tubes must be sub-cultured to Lauryl Tryptose Mannitol Broth CM0831 and incubated at 44°C to detect indole formation at this temperature before the identification of Escherichia coli can be made.

• Oxoid Clostridium Difficile Agar Base is used for the isolation of Clostridium difficile.
• Also available Clostridium Difficile Selective Supplement, Part No. SR0096E.

lostridium Difficile Agar Base, Oxoid Composition

Clostridium Difficile Agar, Oxoid Preparation:
Suspend 34.5g in 500ml of distilled water and bring gently to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Allow to cool to 50°C and add aseptically the contents of 1 vial of Oxoid Clostridium Difficile Supplement (SR0096) reconstituted as directed, together with 7% (v/v) Defibrinated Horse Blood (SR0050). Sheep Blood (SR0051) may be used in place of Horse Blood but some strains of the organism will show a slightly reduced growth recovery. Mix well and pour into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C no longer than 5-7 days.

Precautions
Colonies of Clostridium difficile from faecal cultures are smaller when egg yolk is used in place of horse blood.

The Oxoid formula does not contain the neutral red indicator proposed by George et al. because it is designed for use with horse blood. On this medium the typical colour of the colony of Clostridium difficile will not appear however there will be a fluorescent reaction.

Typical Gram stain morphology of Clostridium difficile may not be evident in colonies picked from this medium because of the antibiotics present. Subculture to blood agar to obtain characteristic morphology.

The Oxoid Tryptone Bile Agar is used for the detection and enumeration of E.coli biotype 1 in foods.

Tryptone Bile Agar, Oxoid Composition

Tryptone Bile Agar, Oxoid Preparation:
Suspend 36.5g in 1 litre of distilled water and bring gently to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50°C and pour 12-15ml of the medium into sterile Petri dishes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared plates at 2-8°C.

• Oxoid Kanamycin Aesculin Azide Agar Base is a selective medium for the isolation of Enterococci in foodstuffs.
• Also available Kanamycin Sulphate Selective Supplement, Part No. SR0092E.

Kanamycin Aesculin Azide Agar Base, Oxoid Composition

Kanamycin Aesculin Azide Agar, Oxoid Preparation:
Suspend 21.3g in 500ml of distilled water. Add one vial of Kanamycin Supplement (SR0092) reconstituted as directed. Bring to the boil. Sterilise by autoclaving at 121°C for 15 minutes.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared media at 2-8°C.

Precautions
Observe the hazard precautions regarding sodium azide when disposing of the medium.
There is no universal medium which will isolate all strains of enterococci.
Unless a presumptive count is acceptable all isolates should have their identity confirmed with further tests.

Oxoid BiGGY Agar (Nickerson Medium) for the isolation and presumptive identification of Candida spp.

BiGGY Agar, Oxoid Composition

BiGGY Agar, Oxoid Preparation:
Suspend 42g in 1 litre of distilled water and bring gently to the boil to dissolve the agar. Allow to cool to 50-55°C. Mix gently to disperse the flocculant precipitate and pour into sterile Petri dishes.
DO NOT AUTOCLAVE THE MEDIUM.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Medium should be freshly prepared just prior to use.

Precautions
Carry out further tests to confirm identity of isolated yeasts.
Do not use slants of medium because the reactions are unsatisfactory.
The flocculent precipitate present in the molten medium must be evenly suspended whilst dispensing the agar.