P-070. The Microbiological Quality of Ready to Use Fresh Salad in Vienna area

M. Manafi;
Hygiene Inst., Vienna, AUSTRIA.

The sale of ready-to-use (RTU) fresh salad sealed in plastic packages and dishes is rapidly increasing. RTU salads are “minimally processed vegetables” and are generally colonized by saprophytic gram-negative flora of water and terrestrial habitat. On the other hand, some researchers have reported the presence of pathogenic microorganisms of human origin in RTU vegetables. In addition, there have been reports of numerous epidemic outbreaks linked to consumption of raw vegetables contaminated by bacteria, viruses and protozoa. The objective of this study was to establish the bacteriological profile of 200 samples including Iceberg lettuce, Chinese cabbage, Endive, Lettuce, Rucola, Corn salad and raw sliced vegetables. Analysis of our samples indicated that a high percent of the samples were positive for water and terrestrial flora. Our investigation revealed that 99.5 % of the samples were positive for coliforms and 96.0% for P. aeruginosa. Mold and Yeast were present in 85% and in 75% of samples respectively. E.coli and enterococci are accepted as hygienic indicator and signify a faecal contamination. E. coli was detected in 41 samples (20.5%) and 36.6% of those had counts of at least 103 cfu/g. Enterococci was present in 53.5% of samples and 32.7% of those had counts of at least 103 cfu/g. Presumptive Spore forming aerobes were isolated from 54.5% of the samples and 27.5% of those had counts of 103 cfu/g or greater. In conclusion, Pseudomonads and coliforms are major components of the indigenous microflora of RTU vegetables and the storage temperature is probably the single most important factor affecting the growth of microorganisms in RTU vegetables. A washing step before use and a storage temperature range of 0- 5 °C is recommended.