Detection of meat contamination with VTEC in the marketing chain of beef in Argentina

ROSANA POLIFRONI; MARCELO E. SANZ; MARÍA C. VILLALOBO; LÍA ELICHIRIBEHETY; EDGARDO M. RODRÍGUEZ; ANALÍA I. ETCHEVERRÍA; NORA L. PADOLA; ALBERTO E. PARMA

Centro Cultural Borges - C.A.B.A

Congreso; VTEC2009 -7th. International Symposium on Shiga Toxin (verocytotoxin)- Producing Escherichia coli Infections – Buenos Aires; 2009

Asociación Argentina de Microbiología

The aim of this study was to detect VTEC in samples of beef half res and cuts of meat in the marketing chain of these foods. Sampling were conducted from August to December of 2007 and were designed based on the beef supply network in the Buenos Aires province and the consumption habits. We took 522 samples: 83 forequarters and 83 hindquarters from slaughterhouses; 59 forequarters and 61 hindquarters from sanitary cabin control; 54 forequarters and 55 hindquarters from butchers; 34 chuck, 34 standing rump and 59 minced beef samples from butchers. The samples were took by swabs following SENASA and international rules, with exception of minced meat that were took 100 g of product. The swabs were carried to laboratory in physiologic solution with 0.1% of peptone. Multiplex PCR for vt1 y vt2 and monoplex PCR for eaeã1 was done in positives samples for vt1 y vt2.  None sample was positive for eaeã1. In general, the number of positives samples to vt was higher in hindquarters (H 14.57%) than in the forequarters (F 5.10%). This rate was constant for half reses from the slaughterhouse (H 10,84%; F 3,61%),  sanitary cabin control (H 14,75%; F 3,39%) and butchers (H 20,00%; F 9,26%). The values show an increase from the slaughterhouse to the butcheries.   When the results were analyzed in term of the supplier of the butcheries (slaughterhouse or meat audited in sanitary cabin control), we found a significantly higher prevalence of VTEC in those provided by audited in sanitary cabin control (H:15.38% slaughterhouse; 31.25% sanitary cabin control; F: 5.26% slaughterhouse; 18.75% sanitary cabin control). A seasonal trend could be observed, with an increase in warm seasons. This phenomenon was more evident for the sanitary cabin control (0.00% on August, 16.67% on December) than in the butcheries (8.33% on August; 13.79% on November). This can be related with an interruption in the cold chain during the transporting time and marketing, while the slaughterhouse’s data show oscillation along the year. We observed VTEC in the 11.76% of meat cuts (standing rump and chuck), and in the 40. 68% of the minced meat samples. This increment of the positive samples to VTEC, from the slaughterhouse and sanitary cabin control to the butcheries, might be related with the meat acidification and the increase in the acidic resistance showed for many serotypes of VTEC. It was observed an increase of VTEC-positive samples in the big butcheries (61.76%) than in the small ones (12%). These results allow to conclude that exists an increment in the VTEC detection when the meat is transported from the slaughterhouse until the sale point, and which becomes more noticeable in warm months. This situation represents an increased risk for the consumers and a challenge for those who are responsible in the beef sanitary control service.