Thermo Scientific™ Raka-Ray Agar Base (Dehydrated)

Description

• Isolate lactic acid bacteria in beer and brewing processes with Thermo Scientific™ Oxoid™ Raka-Ray Agar Base (Dehydrated)
• The medium is based on the formula of Saha, Sondag and Middlekauff 1 and is recommended by the American Society of Brewing Chemists (ASBC) 2 , and the European Brewing Convention (EBC) 3
• Members of the family Lactobacillaceae occurring in the brewing process are important spoilage organisms because products arising from their growth and metabolism are often seriously detrimental to flavor
• Detection is complicated by the diverse nutritional and environmental requirements of the family
• Raka-Ray Agar 1 enables brewers to monitor in-process beer quickly and accurately for a wide range of organisms including pediococci
• Investigations in which various combinations of growth stimulating agents were added to Universal Beer Agar led to the recognition of a number of agents including sorbitan mono-oleate, liver extract, yeast extract and N-acetyl glucosamine which gave superior results in respect of colony size, colony numbers and incubation time when compared with unmodified Universal Beer Agar
• These investigations provided the basis for the formula of Raka-Ray 3 Medium in which sorbitan mono-oleate is included as a stimulant for lactic acid bacteria in general 4
• Fructose is present as the essential carbohydrate source for Lactobacillus fructivorans 5 while maltose is present to detect lactobacilli which cannot utilize glucose 6 .