BACTERIAL SPORE LOAD PROFILE ALONG PRODUCTION CHAIN OF CANNED WHITE ASPARAGUS (ASPARAGUS OFFICINALIS)
Increasing European and American market demand for high quality canned asparagus from Peru has prompted the need to identify and quantify the microbial spore load on fresh asparagus important in the establishment of safe thermal processes. This 2-phase study was made in an asparagus packing and processing company in Peru. In Phase I of the study, soil samples were taken from different field locations throughout the asparagus cultivars during the growing season. In Phase II, asparagus were taken as they moved through the entire production chain from field harvest during the cannery processing line to the retort. Samples were subjected to microbiological analyses to identify and quantify mesophilic aerobic and anaerobic spore-forming bacteria (MAE and MAN) and the respective thermophilic aerobic and anaerobic spores (TAE and TAN). Maximum spore populations found in soil samples were (cfu/g) 3.5×107 MAE, 8.8×105 MAN, 1.2×105 TAE, 4.7×104 TAN. Also found in soil samples were 5.8×104 cfu/g of sulfite reducing bacteria. On freshly harvested asparagus entering the plant on the receiving dock were found (cfu/g) 4.3×104 MAE, 1.2×104 MAN, 8.8×103 TAE, and 1.0×10 TAN. These initial counts subsequently diminished as the asparagus moved through the processing chain after washing and hydro-cooling (which sometimes increased mesophilic anaerobes). As expected, no significant differences were found in thermophilic anaerobes as the asparagus moved through peeling, cutting, blanching and filling operations. Samples taken from the filling line just prior to retorting had 5.5×102 MAE, 1.2×102 MAN, 5.0 TAE and 2.0×10 TAN (cfu/g respectively).
Velezmoro, C., Pahuara, D., Ramos, E., Benites, E., Teixeira, A., Gomero, A. and Zuñiga, D. (2012). BACTERIAL SPORE LOAD PROFILE ALONG PRODUCTION CHAIN OF CANNED WHITE ASPARAGUS (ASPARAGUS OFFICINALIS). Acta Hortic. 950, 207-216
canned vegetable, spore-forming bacteria, production chain, thermal processing, retorting