Monitoring the sensorial and microbiological quality of pasteurized white asparagus at different storage temperatures

Abstract

Changes in sensory quality and proliferation of pathogenic and spoilage microorganisms in pasteurized white asparagus were measured as a function of storage temperature. The main sensorial attributes studied with regard to storage time were the general appearance of the product, turgidity and package swelling. There was a significant correlation between the deterioration in sensorial quality and microbial evolution, which was even more marked at higher temperatures. After 13 days at 4 • C, 6 days at 10 • C, 5 days at 20 • C and 84 h at 30 • C organoleptic deterioration and, consequently, the end of shelf life were detected. A significant growth of spoilage flora was observed, which might be responsible for the drop in pH levels during the final period of analysis (from 6.3 to 3.5-4 until 148 h). There was greater lactic acid bacteria (LAB) growth as the temperature and CO 2 concentration increased, reaching a final concentration of approximately 10 8 CFU g −1 at all temperatures. We found no positive samples of Clostridium spp at 10 and 4 • C. Among the species isolated at 20-30 • C Clostridium septicum and in lower proportions Clostridium perfringens were encountered. The possible presence of Listeria monocytogenes was analyzed, but there were no positive samples in the final product. Pasteurized white asparagus maintains good organoleptic characteristics with a relatively long shelf-life at low temperatures, which leads to an adequate acceptance among consumers.

Growth of Listeria monocytogenes on shredded, ready-to-eat iceberg lettuce

“…These initial loads are consistent with those reported by others authors (García-Gimeno & Zurera-Cosano, 1997;Garg et al, 1990;Valero et al, 2006).…”

Natural color pigments: oxidative stability and degradation kinetics during storage in thermally pasteurized vegetable purees

“…Buckle and Edwards reported a pH drop of 0.38–0.86 units in pea puree processed at 115.6–148.9°C and stored at 20 °C for 18 months. Valero et al . reported a pH drop from 6.3 to 4 in pasteurized (78.2 °C for 14 min) white asparagus as a result of the outgrowth of lactic acid bacteria and other spoilage organisms.…”

Growth potential of Salmonella enterica in thirty‐four different RTE vegetable salads during shelf‐life

“…The initial TBC levels recovered from vegetable salads in this study are comparable with those of previously published studies that have reported counts ranging between 10 2 and 10 8 CFU g −1 (Barriga et al ., 1991; García‐Gimeno & Zurera‐Cosano, 1997; Soriano et al ., 2000; Valero et al ., 2006; Abadias et al ., 2008; Ailes et al ., 2008; Caponigro et al ., 2010; Wood et al ., 2015; Korir et al ., 2016; Nousiainen et al ., 2016; Xylia et al ., 2019; Ziegler et al ., 2019). There may be regional variations in initial levels of TBC reported since type and variety of produce commodity, cultivation peculiarities, state of maturity and processing conditions, packaging, gas composition, other handling, transport and storage conditions, among other factors can affect initial bacterial counts (Lopez‐Velasco et al ., 2010; Leff & Fierer, 2013).…”