Universal Beer Agar - BVA Scientific

Section III
U-Z UVM Modified Listeria, cont.
Expected Results
Refer to appropriate references and procedures for results.
References
1. Murray, Webb and Swann. 1926. J. Pathol. Bacteriol. 29:407.
2. Monk, Clavero, Beuchat, Doyle and Brackett. 1994. J. Food Prot. 57:969.
3. Wehr. 1987. J. Assoc. Off. Anal. Chem. 70:769.
4. Bremer and Osborne. 1995. J. Food Prot. 58:604.
5. Grau and Vanderlinde. 1992. J. Food Prot. 55:4.
6. Patel, Hwang, Beuchat, Doyle and Brackett. 1995. J. Food Prot. 58:244.
7. Ryser and Donnelly. 2001. In Downes and Ito (ed.), Compendium of methods for the microbiological
examination of foods, 4th ed. American Public Health Association, Washington, D.C.
8. Kramer and Jones. 1969. J. Appl. Bacteriol. 32:381.
9. Donnelly and Baigent. 1986. Appl. Environ. Microbiol. 52:689.
10. McClain and Lee. May 24, 1989. Laboratory communication No. 57. Microbiology Division, Food
Safety and Inspection Service, U.S. Department of Agriculture, Beltsville, Md.
11. Bille, Rocourt and Swaminathan. 1999. In Murray, Baron, Pfaller, Tenover and Yolken (ed), Manual
of clinical microbiology, 7th ed. American Society for Microbiology, Washington, D.C.
12. Hayes, Graves, Swaminathan, Ajello, Marcolm, Weaver, Ransom, Deaver, Plikaytis, Schuchat, Wenger,
Pinner, Broome and The Listeria Study Group. 1992. J. Food. Prot. 55:952.
Availability
Difco UVM Modified Listeria Enrichment Broth
AOAC COMPF
Cat. No. 222330 Dehydrated – 500 g
222310 Dehydrated – 2 kg
222320 Dehydrated – 10 kg
Universal Beer Agar
Intended Use
Universal Beer Agar (UBA Medium) is used for cultivating
microorganisms of significance in the brewing industry.
Summary and Explanation
Universal Beer Agar is a basal medium to which beer is added.
It is based on the formula developed by Kozulis and Page 1
who compared it with other media commonly used in breweries
for detecting microbial contamination. 2 The characteristics of
Universal Beer Agar are closer to the natural environmental
conditions found in the typical brewery than other media studied.
It supports growth of more varieties of lactic acid bacteria and
yields larger colonies in a shorter time than traditional brewer’s
media. Due to the presence of beer in the medium, it is
selective for growth of microorganisms that have adapted
User Quality Control
Identity Specifications
Difco Universal Beer Agar
Dehydrated Appearance: Medium beige, homogeneous, freeflowing.
Solution:
6.2% solution, soluble in purified
water upon boiling. Solution is medium
to dark amber, very slightly opalescent.
Prepared Appearance: Medium to dark amber, very slightly
opalescent.
Reaction of 6.2%
Solution at 25°C: pH 6.3 ± 0.2
Cultural Response
Difco Universal Beer Agar
Prepare the medium per label directions. Inoculate and incubate at
30 ± 2°C for up to 3 days.
ORGANISM ATCC INOCULUM CFU RECOVERY
Acetobacter pasteurianus 12879 10 2 -10 3 Good
Lactobacillus fermentum 9338 10 2 -10 3 Good
Lactobacillus johnsonii 11506 10 2 -10 3 Good
Pediococcus acidilactici 8081 10 2 -10 3 Good
themselves to existent conditions in the brewery. The presence
of hop constituents and alcohol inhibits growth of many airborne
microorganisms not adapted to this environment. 3
Universal Beer Agar supports growth of Lactobacillus,
Pediococcus, Acetobacter and yeast strains which may be found
contaminating the wort and beer.
Principles of the Procedure
Yeast extract is a source of trace elements, vitamins and amino
acids. Peptonized milk contains lactose as an energy source.
Tomato juice is a source of carbon, protein and nutrients.
Dextrose provides additional carbon. Dipotassium and
monopotassium phosphates provide buffering capability.
Magnesium sulfate, ferrous sulfate and manganese sulfate are
sources of ions that stimulate metabolism. Sodium chloride
provides essential ions. Agar is the solidifying agent.
Formula
Difco Universal Beer Agar
Approximate Formula* Per Liter
Yeast Extract .............................................................. 6.1 g
Peptonized Milk ....................................................... 15.0 g
Tomato Juice (from 244 mL) ..................................... 12.2 g
Dextrose ................................................................... 16.1 g
Dipotassium Phosphate .............................................. 0.31 g
Monopotassium Phosphate ........................................ 0.31 g
Magnesium Sulfate .................................................... 0.12 g
Sodium Chloride ........................................................ 6.0 mg
Ferrous Sulfate ........................................................... 6.0 mg
Manganese Sulfate .................................................... 6.0 mg
Agar ......................................................................... 12.0 g
*Adjusted and/or supplemented as required to meet performance criteria.
Directions for Preparation from
Dehydrated Product
1. Suspend 62 g of the powder in 750 mL of purified water
(or halogen-free tap water). Mix thoroughly.
2. Heat with frequent agitation and boil for 1 minute to
completely dissolve the powder.
3. While the medium is still hot, add 250 mL commercial beer
(not degassed) and mix well.
604

Universal Preenrichment Broth
4. Autoclave at 121°C for 10 minutes.
5. Test samples of the finished product for performance using
stable, typical control cultures.
Procedure
See appropriate references for specific procedures.
Expected Results
Refer to appropriate references and procedures for results.
References
1. Kozulis and Page. 1968. Proc. Am. Soc. Brewing Chemists, p. 52.
2. Murphy and Saletan. 1970. Tech. Q. Master Brew. Assoc. Am. 7:182.
3. MacFaddin. 1985. Media for isolation-cultivation-identification-maintenance medical bacteria, vol.
1. Williams & Wilkins, Baltimore, Md.
Availability
Difco Universal Beer Agar
Cat. No. 285610 Dehydrated – 500 g
Mexico
Cat. No. 252644 Prepared Plates (60 × 15 mm-style) – Pkg. of 20*
*Store at 2-8°C.
Universal Preenrichment Broth
Intended Use
Universal Preenrichment Broth is used for recovering sublethally
injured Salmonella and Listeria from food products.
Summary and Explanation
Traditional methods for recovering Salmonella and Listeria
from food products require separate preenrichment media for
each microorganism. 1,2 Some broth media recommended
for preenrichment contain antibiotic inhibitors 3 or have
insufficient buffering capacity which hinder recovery of sublethally
injured cells. 3-5
Bailey and Cox 3 formulated Universal Preenrichment Broth to
permit simultaneous resuscitation of sublethally injured
Salmonella and Listeria. The broth medium provides sufficient
buffering capacity to prevent rapid decreases in pH and
allows for repair of injured cells that might be sensitive to low
pH values or inhibitory substances.
Principles of the Procedure
Universal Preenrichment Broth contains peptones as sources
of carbon, nitrogen, vitamins and minerals. Sodium and
potassium phosphates buffer the medium. Sodium chloride
maintains the osmotic balance of the medium. Magnesium
sulfate and ferric ammonium citrate provide essential ions.
Dextrose is an energy source. Sodium pyruvate helps stimulate
the metabolism of stressed organisms.
User Quality Control
Identity Specifications
Difco Universal Preenrichment Broth
Dehydrated Appearance: Light beige, free-flowing, homogeneous.
Solution:
3.8% solution, soluble in purified
water. Solution is light to medium
amber, slightly opalescent to opalescent,
may have a precipitate.
Prepared Appearance: Light to medium amber, slightly opalescent
to opalescent, may have a
precipitate.
Reaction of 3.8%
Solution at 25°C: pH 6.3 ± 0.2
U -
Z
Cultural Response
Difco Universal Preenrichment Broth
Prepare the medium per label directions. Inoculate and incubate at 35 ±
2°C for 18-24 hours.
ORGANISM ATCC INOCULUM CFU RECOVERY
Listeria monocytogenes 19115 10-10 2 Good
Salmonella choleraesuis subsp.
choleraesuis serotype Enteritidis 13076 10-10 2 Good
Salmonella choleraesuis subsp.
choleraesuis serotype Typhimurium 14028 10-10 2 Good
Uninoculated
Tube
Salmonella
typhimurium
ATCC 14028
605