Ja. Straub et al., A 23S rDNA-targeted polymerase chain reaction-based system for detection of Staphylococcus aureus in meat starter cultures and dairy products, J FOOD PROT, 62(10), 1999, pp. 1150-1156
A polymerase chain reaction-based system for detection of Staphylococcus au
reus was developed. The system consisted of the following components: (i) s
elective enrichment, (ii) DNA isolation, (iii) amplification of DNA with pr
imers targeted against the 23S rRNA gene, and (iv) evaluation of the specif
icity of the polymerase chain reaction by Southern hybridization and nested
polymerase chain reaction. The method achieved a high degree of sensitivit
y and unambiguity as required for the detection of contaminants in food sta
rter preparations. The method permitted detection of Staphylococcus aureus
in preparations of meat starter cultures containing Staphylococcus carnosus
either alone or in combination with lactobacilli, pediococci, and/or Kocur
ia varians. Detection limits were sufficiently low to show within 12 h the
presence of 10(0) CFU of S. aureus in starter preparations containing 10(10
) CFU of S. carnosus. The system was also applied to dried skim milk and cr
eam. For detection without selective enrichment, a protocol was developed a
nd permitted detection of 120 CFU of S. aureus in 1 ml of cream within 6 h.
With nested polymerase chain reaction, the detection limit was decreased b
y one order of magnitude.