Inactivation of Salmonella Enteritidis on lettuces used by minimally processed vegetable industries

Abstract

Introduction: Washing and disinfection methods used by minimally processed vegetable industries of Southern Brazil were reproduced in laboratory in order to verify their effectiveness to reduce Salmonella Enteritidis SE86 (SE86) on lettuce. Methodology: Among the five industries investigated, four carried out washing with potable water followed by disinfection with 200 ppm sodium hypochlorite during different immersion times. Results: The washing procedure alone decreased approximately 1 log CFU/g of SE86 population and immersion times of 1, 2, 5, and 15 minutes in disinfectant solution demonstrated reduction rates ranging from 2.06±0.10 log CFU/g to 3.01±0.21 log CFU/g. Rinsing alone was able to reduce counts from 0.12±0.63 log CFU/g to 1.90±1.07 log CFU/g. The most effective method was washing followed by disinfection with 200 ppm sodium hypochlorite for 15 minutes and final rinse with potable water, reaching 5.83 log CFU/g of reduction. However, no statistical differences were observed on the reduction rates after different immersion times. Conclusion: A time interval of 1 to 2 minutes may be an advantage to the minimally vegetable processed industries in order to optimize the process without putting at risk food safety.

Microbiological quality and safety of minimally processed parsley ( Petroselinum crispum ) sold in food markets, southeastern Brazil

“…2012; Silveira et al . 2017; Yoon and Lee 2018). Nonetheless, the occurrence of the genus Listeria in these products represents a risk for the presence of the pathogenic species (e.g.…”

Salmonella enterica Control in Stick Carrots Through Incorporation of Coriander Seeds Essential Oil in Sustainable Washing Treatments

“…In addition, strains belonging to this genus form biofilms on many food contact surfaces of processing equipment (e.g., cutting boards, knives) with consequent crosscontamination of vegetables (Lo Fo Wong et al, 2002;Doulgeraki et al, 2016). Effective intervention methods able to reduce Salmonella infections are based on washing and sanitization procedures, principally utilizing chemical disinfectants (e.g., chlorinated water, Silveira et al, 2017;Ramos et al, 2020). However, these chemical agents present several disadvantages in terms of safety and sustainability.…”

Risk of infection withSalmonella andEscherichiacoli O157:H7 due to consumption of lettuce in southern Brazil

“…19 The process considered the washing of lettuce using potable water followed by immersion in 200 ppm of sodium hypochlorite sanitizer for 15 minutes and rinsing with potable water. Silveira et al 20 studied the Salmonella reduction, using this procedure, reported levels of 5.83±0.82 log CFU/g, while De Paula 21 demonstrated reductions levels of 6.27±0.50 log CFU/g for E. coli O157:H7, using the same process; in both studies bacteria were artificially inoculated on lettuce. These levels of reductions were used in the present study.…”

“…The exposure adopted by scenario 5 was half of the exposure used in the real-world scenario (15 days per month). Each scenario was run in @Risk using 100,000 iterations with generator seed fixed at 1 Furthermore, different washing and disinfection procedures were tested: scenario 6 considered washing of lettuce using only potable water [reducing 0.97±0.18 for Salmonella, and 1,49±0.18 for E. coli O157:H7 according to Silveira et al, 20 and De Paula et al 21 )]; scenario 7 considered washing with potable water followed by immersion in 200 ppm of sodium hypochlorite sanitizer for 1 minute and rinsing with potable water [reducing 5.11±0.82 for Salmonella, and 3.27±0.27 for E. coli O157:H7 according to Silveira et al, 20 and De Paula et al 21 ]; and scenario 8 considered washing of lettuce with potable water followed by immersion in 200 ppm of sodium hypochlorite sanitizer for 5 minutes and rinsing with potable water [reducing 4.41±0.48 for Salmonella, and 2.76±0.26 for E. coli O157:H7 according to Silveira et al, 20 and De Paula et al 21 ]. The scenario 9 evaluated the impact of control of temperature (maximum temperature 5ºC) from storage at farms until home storage on risks and on number of cases of infection, it was modeled using a Pert distribution with 1ºC, 3ºC and 5ºC as minimum, most likely and maximum values.…”