Plant-Microbe and Abiotic Factors Influencing Salmonella Survival and Growth on Alfalfa Sprouts and Swiss Chard Microgreens

Abstract

17Microgreens, like sprouts, are relatively fast growing, and generally consumed raw. Moreover, as 18 observed in sprouts, microbial contamination from preharvest sources could also be present in 19 the production of microgreens. In this study, two Salmonella enterica serovars (Hartford and 20 Cubana) applied, at multiple inoculation levels, were evaluated for survival and growth on alfalfa of Salmonella in both alfalfa sprouts and microgreens was largely affected by inoculation level.31 Surprisingly, growing medium was found to play an important role in Salmonella survival and 32 growth in microgreens. CLPP analysis showed significant changes in the microbial community 33 metabolic diversity during sprouting for alfalfa sprouts, but few temporal changes were seen in 34 microgreens. The data suggest that the change in rhizosphere bacterial functional diversity was 35 host-dependent but independent of Salmonella contamination.

Microgreen nutrition, food safety, and shelf life: A review

“…Wright and Holden () did not test STEC growth/survival on microgreens grown in soil substitute. Reed, Ferreira, Bell, Brown, and Zheng () found that Salmonella enterica was at least as successful at surviving and growing on Swiss chard microgreens as on alfalfa sprouts and successful colonization was inoculum level dependent. However, S. enterica growth on seed‐inoculated alfalfa sprouts was also affected by seed storage time, while on Swiss chard microgreens it was dependant on serovar.…”

“…Recently, studies have demonstrated that microgreen growing systems, especially hydroponic systems, are vulnerable to pathogen proliferation when seeds are contaminated, highlighting the importance of seed sanitation (Reed et al., ; Wright & Holden, ; Xiao et al., ). Xiao et al.…”

“…Reed et al. () reported that the type of growth medium played an important role in serovar‐dependant Salmonella survival and growth on microgreens irrigated with contaminated water. Of the different growth media tested, hydroponic pads resulted in the highest percentage of Salmonella ‐positive samples and the highest Salmonella population level on microgreens.…”

Survival of Salmonella enterica subsp. enterica serovar Javiana and Listeria monocytogenes is dependent on type of soil‐free microgreen cultivation matrix

“…For example, Reed et al . (2018) found a statistically significant difference ( P = 0·01) between the concentration of Salmonella serovars Cubana and Hartford in Swiss chard microgreens when contaminated seeds were planted in soil (75–85% sphagnum peat moss, peat humus, perlite, earthworm castings and dolomitic limestone). S .…”

“…(2014, 2015) and Reed et al . (2018). Normality of the log transformed data was determined using QQ plots.…”