Efficacy of a Commercial Produce Wash on Bacterial Contamination of Lettuce in a Food Service Setting

Abstract

Many microorganisms (including a number of important foodborne pathogens) can be present on raw fruits and vegetables. Since these products are frequently eaten raw, any pathogens present represent a potential risk to the consumer. The objective of this study was to compare the efficacy of a commercial produce wash with that of water for reducing the total bacterial population on lettuce when used by food service employees in university dining halls. Because this study was carried out in actual food service facilities during their daily operation, we used indigenous produce microflora instead of actual pathogens. Over the course of the study, more than 40 heads of lettuce were divided into thirds, and each section was analyzed for total plate count either before washing, after washing in water, or after washing in Victory produce wash. When initial contamination levels were > or = 100 CFU/g (n = 36 samples), reductions obtained with Victory produce wash (1.8 log CFU/g) were significantly larger (P = 0.0006) than those obtained with water (0.8 log CFU/g). Our results indicate that Victory produce wash is effective in reducing indigenous flora on lettuce during food service preparation. Our results also show that care must be taken in the analysis of microbial reduction data: only a slight reduction in total plate count (ca. 0.1 log CFU/g) and no significant difference in reductions (P = 0.84) were observed when all samples (irrespective of initial contamination level) were compared.

Cross‐Contamination During Food Preparation: A Mechanistic Model Applied to Chicken‐Borne Campylobacter

“…For the salad, it will probably be more effective to encourage a more thorough rinsing than to try to increase the number of people who rinse their salad. Data by Smith et al (2003) seem to indicate that efficient washing requires 1 to 2 minutes of rinsing, with a maximum effect of about 1 10 log reduction if rinsing in water, and a 2 10 log reduction if sanitizing chemicals are used. Therefore, it might even be better to let people prepare raw-consumed food items before the possibly contaminated items.…”

“…Table I lists numerical values and references to literature sources of transfer probabilities. Data were taken from Chen et al (2001) and Montville Estimated from Montville et al (2001); see also Chen et al (2001), Table 1 2 Kusumaningrum et al (2004); see also Chen et al (2001), Table 3 3 Estimated from Chen et al (2001), Table 1 4 Chen et al (2001), Table 4 5 Estimated from Smith et al (2003) 6 Estimated from Cogan et al (2002) et al (2001)-who use data on Enterobacter aerogenes, which has adhesion characteristics similar to Salmonella-and Cogan et al (2002) and Smith et al (2003)-who studied washing both in water and with a commercially produced wash; we used the water data-and Kusumaningrum et al (2004)-who use data on Salmonella and Campylobacter spp. Probabilities of transfer as well as persistence are on an individual CFU basis, per action performed.…”

Prediction of coliforms and Escherichia coli on tomato fruits and lettuce leaves after sanitizing by using Artificial Neural Networks

“…Note that this initial starting load is not an unrealistic load for actual raw vegetables and fruits. For example, aerobic plate counts for unwashed lettuce samples have been reported to be at about 5 log 10 cfu/g (Smith, Dunbar, Tucker, & Schaffner, 2003;Vijayakumar & Wolf-Hall, 2002). Moreover, aerobic and coliforms counts in raw salads and related vegetables have also been reported at 5e9 log 10 cfu/g (Viswanathan & Kaur, 2001).…”

“…Hilgren and Salverda (2000) reported that peracetic acid (80 ppm) could reduce aerobic bacteria by 1.07, 0.84 and 1.54 log 10 cfu/g in celery, cabbage and potatoes, respectively. Finally, Smith et al (2003) indicated that the average total plate count values decreased from 3.4 AE 1.2 to 2.0 AE 1.3 versus 3.0 AE 1.0 log 10 cfu/g when lettuce was washed in Victory (water contained 60 ppm of hydrogen peroxide and peroxyacetic acid) or water, respectively. Thus, a Victory sanitizing wash was more effective in reducing the indigenous microflora on lettuce leaves in an actual food service setting compared to that obtained with water.…”

Expanded Fermi Solution for Estimating the Survival of Ingested Pathogenic and Probiotic Microbial Cells and Spores

“…Notice that except under strictly controlled laboratory conditions, the terms "washed," "refrigerated," "cooked," and "baked" are not clearly defined. But even in controlled experiments, the survival of pathogens and other microorganisms can vary by as much as an order of magnitude and even more (2,9,10,19,24). Thus, determining by how much food storage and preparation reduce the number of cells or spores of interest would require a substantial amount of data and might still yield inconclusive results.…”