Nature versus Nurture: Assessing the impact of strain diversity and pre-growth conditions on Salmonella enterica, Escherichia coli, and Listeria spp. growth and survival on selected produce items.

Nature versus Nurture: Assessing the impact of strain diversity and pre-growth conditions on Salmonella enterica, Escherichia coli, and Listeria spp. growth and survival on selected produce items. Appl Environ Microbiol. 2021 Jan 04;: Authors: Harrand AS, Guariglia-Oropeza V, Skeens J, Kent D, Wiedmann M Abstract Inoculation studies are important when assessing microbial survival and growth in food products. These studies typically involve the pre-growth of multiple strains of a target pathogen under a single condition; this emphasizes strain diversity. To gain a better understanding of the impacts of strain diversity ("Nature") and pre-growth conditions ("Nurture") on subsequent bacterial growth in foods, we assessed the growth and survival of S. enterica (n=5), E. coli (n=6) and Listeria (n=5) inoculated onto tomatoes, pre-cut lettuce and cantaloupe rind, respectively. Pre-growth conditions included (i) 37°C to stationary phase ("baseline") as well as (ii) low pH, (iii) high salt, (iv) reduced water activity, (v) log phase, (vi) minimal medium, and (vii) 21°C. Inoculated tomatoes were incubated at 21°C; lettuce and cantaloupe were incubated at 7°C. Bacterial counts were assessed over three phases, including initial reduction ("phase 1"), change in bacterial numbers over the first 24 h of incubation ("phase 2"), and change over the 7-day incubation ("phase 3"). E. coli showed overall decline in counts (<1 log) over the 7-day ...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research