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Detection of Listeria monocytogenes in Italian‐style soft cheeses
Author(s) -
Longhi C.,
Maffeo A.,
Penta M.,
Petrone G.,
Seganti L.,
Conte M.P.
Publication year - 2003
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2003.01921.x
Subject(s) - listeria monocytogenes , biology , polymerase chain reaction , microbiology and biotechnology , virulence , genomic dna , food science , gene , bacteria , genetics
Aims: A rapid detection system specific for Listeria monocytogenes and based on the polymerase chain reaction (PCR) was developed. Methods and Results: Primers annealing to the coding region of the actA gene, critically involved in virulence and capable of discrimination between two different alleles naturally occurring in L. monocytogenes , have been utilized. The procedure was applied to recover L. monocytogenes cells in artificially contaminated fresh Italian soft cheeses (mozzarella, crescenza and ricotta). Low levels of L. monocytogenes were detected in mozzarella and crescenza homogenates (0·04–0·4 and 4 CFU g −1 , respectively) whereas in ricotta the detection limit was higher (40 CFU g −1 ). Conclusions: This PCR‐based assay is highly specific as primers used recognize the DNA from different L. monocytogenes strains of clinical and food origin, while no amplification products result with any other Listeria spp. strains. Significance and Impact of the Study: This study highlighted a low‐cost and rapid procedure that can be appropriated for the detection in real time of low L. monocytogenes levels in soft cheese.