Thursday, May 12, 2016
Megaron Athens International Conference Center
Guerrino Macori, Laboratorio Controllo Alimenti - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
Alberto Bellio, Laboratorio Controllo Alimenti - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
Silvia Gallina, Italian NRL for CPS - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle dÂ’Aosta, Turin, Italy
Clara Ippolito, Laboratorio Controllo Alimenti - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
Daniela Manila Bianchi, Laboratorio Controllo Alimenti - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d'Aosta, Torino, Italy
Fabio Zuccon, Italian NRL for CPS - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta, Torino, Italy
Yacine Nia, Université Paris-Est, ANSES, Laboratory for Food Safety, F-94700 Maisons-Alfort, France
Jacques-Antoine Hennekinne, Université Paris-Est, ANSES, Laboratory for Food Safety, F-94700 Maisons-Alfort, France
Frédéric Auvray, Université Paris-Est, ANSES, Laboratory for Food Safety, F-94700 Maisons-Alfort, France
Dario Bossi, Servizio Veterinario Area C, Azienda Sanitaria Locale, Vercelli, Italy
Lucia Decastelli, Italian NRL for CPS - Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle dÂ’Aosta, Turin, Italy
Introduction: Small dairy productions have a high value in terms of cultural and quality of products and represent a significant economic resource but are often conditioned by the territories of production and the technologies applied. One of the hazards for dairy products is the presence of Staphylococcal Enterotoxins (SEs) in raw milk cheeses that typically have a heterogeneous distribution.
Purpose: In this work we studied the distribution of Coagulase Positive Staphylococci (CPS) and SEs in naturally contaminated cheeses, in order to establish the impact of the sampling sites.
Methods: Seven cheeses were analyzed for CPS enumeration (ISO 6888-2) and detection of SEs (European Screening Method). Each cheese was sampled on four different areas: peripheral and central rind, peripheral and central core. From each sample, up to two CPS isolates were identified and characterized for the presence of SE genes (multiplex PCR) and biotyped. In parallel, SEs were quantified (in house ELISA).
Results: The presence of CPS was observed in 23 (82%) samples; CPS amount ranged from <10 to 5.6x103 cfu/g for the core portions and from 2.0x103 to 8.6x106 cfu/g for the rind portions. Forty-eight isolates were identified as S. aureus; of these, 33 presented Human biotype (69%) and 15 Not-Specific Host (NSH) biotypes. In addition, we identified six different SE gene profiles that, combined with the biotype, permitted the identification of 10 profiles. SEA and SED were quantified in the seven cheeses with concentrations ranging from 0.011 to 2.71 ng/g and from 0.061 to 8.980 ng/g, respectively. These concentrations varied depending on the cheese and the area sampled.
Significance: This work underlined the heterogeneous distribution of CPS and SE in naturally contaminated cheeses highlighting potential sampling issue for CPS enumeration as well as SEs detection.
