Microbiological quality and safety assessment of lettuce production in Brazil.

The microbiological quality and safety of lettuce during primary production in Brazil were determined by enumeration of hygiene indicators Escherichia coli, coliforms and enterococci and detection of enteric pathogens Salmonella and E. coli O157:H7 in organic fertilizers, soil, irrigation water, lettuce crops, harvest boxes and worker's hands taken from six different lettuce farms throughout the crop growth cycle. Generic E. coli was a suitable indicator for the presence of Salmonella and E. coli O157:H7, while coliforms and enterococci were not. Few pathogens were detected: 5 salmonellae and 2 E. coli O157:H7 from 260 samples, of which only one was lettuce and the others were manure, soil and water. Most (5/7) pathogens were isolated from the same farm and all were from organic production. Statistical analysis revealed the following environmental and agro-technical risk factors for increased microbial load and pathogen prevalence in lettuce production: high temperature, flooding of lettuce fields, application of contaminated organic fertilizer, irrigation with water of inferior quality and large distances between the field and toilets. Control of the composting process of organic fertilizers and the irrigation water quality appear most crucial to improve and/or maintain the microbiological quality and safety during the primary production of lettuce.

Evaluation of two recommended disinfection methods for cleaning cloths used in food services of southern Brazil

In the State of Rio Grande do Sul (RS), Southern Brazil, a good manufacturing practices regulation was published recommending two disinfection methods for cleaning cloths used in food services. The aim of the present study was to evaluate the efficacy of those methods. Cleaning cloths were sampled without prior notice at food services, on common working days. For the analyses, the cloths were divided in two sub-samples, being one of them microbiologically analyzed. The second sub-sample was further divided in two pieces and submitted to hand washing for two minutes. After that, one piece was boiled in water for 15 min and the other one was soaked in a 200 ppm sodium hypochlorite solution for 15 min. Both pieces of cloth were submitted to microbiological analyses. Cleaning cloths presented total aerobic mean counts of 6.9 ± 6.7 log/cm². All cleaning cloths presented coliform contamination, and 40% demonstrated mean counts of 6.2 ± 5.6 log/cm². Presumptive S. aureus mean counts of 5.5 ± 4.9 log/cm² were found. No statistic correlation was observed among the number of meals served daily in the food services and the microbiological contamination levels. After washing and disinfection, microbiological counts were significantly (p < 0.05) reduced by both methods, achieving an approximately 5 log reduction. The reductions achieved by the sodium hypochlorite soaking method and the boiling method were not significantly different. Thus, it was possible to conclude that both recommended methods were suitable to disinfect cleaning cloths used in food services.

Evaluation of two recommended disinfection methods for cleaning cloths used in food services of southern Brazil.

In the State of Rio Grande do Sul (RS), Southern Brazil, a good manufacturing practices regulation was published recommending two disinfection methods for cleaning cloths used in food services. The aim of the present study was to evaluate the efficacy of those methods. Cleaning cloths were sampled without prior notice at food services, on common working days. For the analyses, the cloths were divided in two sub-samples, being one of them microbiologically analyzed. The second sub-sample was further divided in two pieces and submitted to hand washing for two minutes. After that, one piece was boiled in water for 15 min and the other one was soaked in a 200 ppm sodium hypochlorite solution for 15 min. Both pieces of cloth were submitted to microbiological analyses. Cleaning cloths presented total aerobic mean counts of 6.9 ± 6.7 log/cm(2). All cleaning cloths presented coliform contamination, and 40% demonstrated mean counts of 6.2 ± 5.6 log/cm(2). Presumptive S. aureus mean counts of 5.5 ± 4.9 log/cm(2) were found. No statistic correlation was observed among the number of meals served daily in the food services and the microbiological contamination levels. After washing and disinfection, microbiological counts were significantly (p < 0.05) reduced by both methods, achieving an approximately 5 log reduction. The reductions achieved by the sodium hypochlorite soaking method and the boiling method were not significantly different. Thus, it was possible to conclude that both recommended methods were suitable to disinfect cleaning cloths used in food services.

Evaluation of bacterial multiplication in cleaning cloths containing different quantities of organic matter.

INTRODUCTION: To determine a proper length of time for cleaning cloth usage, the present work aimed to evaluate bacterial multiplication in artificially contaminated cleaning cloths containing different amounts of organic matter. METHODOLOGY: Cloths containing 1%, 5%, and 10% of bovine albumin were contaminated with Salmonella enteritidis 3091/05, Escherichia coli ATCC 25972, Staphylococcus aureus ATCC 25923, and Shigella sonnei CC07. They were incubated for different time periods at 30°C. Microbial multiplication was evaluated by bacterial counts and the ATP bioluminescence increase was monitored at sampling points. An ampicillin-resistant recombinant HSα E. coli strain was used as a pathogen surrogate to investigate the potential of microbial cloth dispersion. RESULTS: None of the strains showed expressive growth up to two hours of incubation. At three hours, the microorganisms demonstrated a slight increase, with E. coli ATCC 25972 showing a significant increase in cells (p < 0.05). The ATP bioluminescence did not increase during the incubation period and confirmed the microbial count results, demonstrating that the amounts of organic matter tested did not interfere with bacterial multiplication during the first three to four hours of incubation. The dispersion experiment indicated that a cleaning cloth contaminated with 104 CFU/cm² was able to spread 10² CFU/cm² of recombinant E. coli onto a stainless steel surface. CONCLUSION: Based on these results, we suggest that an appropriate period of time for using disinfected cleaning cloths is around two hours, not exceeding three hours of usage.