Predominance and persistence of a single clone of Listeria ivanovii in a Manchego cheese factory over 6 months.
In an attempt to study the diversity and persistence of molecular subtypes of pathogenic Listeria spp. in a cheese factory at the La Mancha region of Spain, 43 samples were taken from incoming raw milk (cow's, ewe's, goat's and mixed species) and from certain food-contact and environmental surfaces before and/or after sanitation. Of these samples, 12 contained pathogenic Listeria. From the chromogenic agar plates corresponding to those, 46 phosphatidylinositol-specific phospholipase C-positive isolates were randomly taken for further analysis, including biochemical tests and pulsed-field gel electrophoresis (PFGE). They coincided in identifying all the 46 as Listeria ivanovii subsp. ivanovii, apparently a single PFGE type. Both ewe's and goat's raw milk batches from asymptomatic animals tested along the 6-month period persistently carried the same strain, which was also obtained from inner surfaces of raw milk truck tanks and the milk dump tank at the cheese factory. Biofilm-forming abilities of this L. ivanovii clone and interference against L. monocytogenes Scott A reference strain were tested, but failed to account for the clone's apparent pervasive presence.
Vázquez-Villanueva
J
J
Departamento de Nutrición, Bromatología y Tecnología de Alimentos, Universidad Complutense de Madrid, Madrid, Spain.
Orgaz
B
B
Ortiz
S
S
López
V
V
Martínez-Suárez
J V
JV
SanJose
C
C
D000818:Animals; D002417:Cattle; D002611:Cheese / Q000382:microbiology; D016521:Electrophoresis, Gel, Pulsed-Field; D004783:Environmental Microbiology; D019649:Food Industry; D005516:Food Microbiology; D006041:Goats; D008087:Listeria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008892:Milk / Q000382:microbiology*; D054801:Phosphoinositide Phospholipase C; D012756:Sheep; D013030:Spain; D013997:Time Factors
D054801:Phosphoinositide Phospholipase C