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

AIMS: This study evaluated the microbiological quality and safety of minimally processed parsley sold in southeastern Brazilian food markets. METHODS AND RESULTS: One hundred samples were submitted to the enumeration of Enterobacteriaceae by plating on MacConkey agar. Colonies of Enterobacteriaceae were randomly selected and identified by MALDI-TOF MS. Samples were also tested for Listeria monocytogenes and Salmonella sp. The mean count of Enterobacteriaceae was 6·0 ± 1·0 log CFU per gram, while 18 genera (including 30 species) of bacteria belonging to this family were identified. Salmonella and L. monocytogenes were not detected, while L. innocua was found in two samples and L. fleischmannii was found in one sample. Moreover generic Escherichia coli was found in three samples, all from different brands of minimally processed parsley. CONCLUSIONS: Even though microbial pathogens were not isolated, a variety of indicator micro-organisms were identified, including vegetable spoilers and species capable of causing human opportunistic infections. These results suggest hygienic failures and/or lack of temperature control during processing and storage of these ready-to-eat products. SIGNIFICANCE AND IMPACT OF STUDY: This study highlights the need for control measures during the production chain of minimally processed parsley in order to reduce microbial contamination and the risks of foodborne diseases.

Assessment of the microbiological quality and safety of minimally processed vegetables sold in Piracicaba, SP, Brazil.

The present study shows the results of the microbiological quality and safety of minimally processed vegetables sold in supermarkets and grocery stores located in the city of Piracicaba, SP, Brazil. A total of 100 samples were collected and submitted to enumeration of total coliforms, coliforms at 45°C and generic Escherichia coli using the standard most probable number (MPN) method, in addition to enumeration of total Enterobacteriaceae by plating on MacConkey agar. Moreover, colonies of Enterobacteriaceae were randomly selected and submitted to identification on a MALDI-TOF MS Biotyper™. Samples were also tested for Salmonella spp. according to the ISO 6579:2002 method. The mean count of total coliforms was 2·9 ± 0·5 log MPN per g. For coliforms at 45°C, 20 samples were positive (mean 1·5 ± 1·0 log MPN per g). Generic E. coli was detected in 16 samples (mean 1·4 ± 0·9 log MPN per g) and only one was positive for Salmonella. The mean count of total Enterobacteriaceae was 6·5 ± 1·2 log CFU per g and the most frequent genera identified by MALDI-TOF were Enterobacter (25·9%), Pantoea (9·6%) and Rahnella (9·0%). Overall, results point to poor microbiological quality of a few samples, indicating hygiene failure during their processing. This can pose health risks to consumers, mainly because these products were labelled as sanitized and marketed as ready-to-eat. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, the microbiological quality and safety of minimally processed vegetables sold in the city of Piracicaba, SP, Brazil, were evaluated through the detection of Salmonella spp., generic Escherichia coli and other Enterobacteriaceae. The results obtained point to poor microbiological quality and safety of a few samples, as generic E. coli was detected in 16 out of 100 samples and Salmonella was isolated from one of them. This indicates hygiene failures during their processing and health risk to consumers, since these products are usually sold as ready-to-eat and typically require no further heat treatment before consumption.

Assessing the relationship between organic farming practices and microbiological characteristics of organic lettuce varieties (Lactuca sativa L.) grown in Sao Paulo, Brazil.

AIMS: This study aimed to gather information on farming practices employed in organic lettuce fields in Sao Paulo, Brazil and associate these practices with the microbiological characteristics of the products. METHODS AND RESULTS: Practices were surveyed using a questionnaire applied in ten farms, where 200 heads of lettuce were collected and submitted to enumeration of total coliforms and generic Escherichia coli and tested for Salmonella spp. using culture and molecular (qPCR) methods. Based on the responses, the farms could be clustered in two groups: group 1, comprised by six farms, where chicken manure was used as fertilizer in most of them and the composting process was not performed on site; and group 2, comprised by four farms, where other types of fertilizer were used, and the composting process was performed on site. Generic E. coli was detected in 56 (28%) samples, with an average of 1·1 ± 0·7 log MPN per g. Salmonella DNA was detected in two (1%) samples by qPCR. CONCLUSIONS: The prevalence and bacterial loads of generic E. coli, and the occurrence of Salmonella, even at low populations undetectable by conventional culture methods, highlight the need for control measures during farming practices to reduce microbial contamination and risks of foodborne illnesses. These measures include the use of properly composted manure and appropriate washing procedures for leafy vegetables before consumption. SIGNIFICANCE AND IMPACT OF THE STUDY: The obtained data contribute to a better understanding of the farming practices of organically grown lettuces in Sao Paulo, Brazil.

Assessing the effect of sodium dichloroisocyanurate concentration on transfer of Salmonella enterica serotype Typhimurium in wash water for production of minimally processed iceberg lettuce (Lactuca sativa L.).

UNLABELLED: This study evaluated the impact of sodium dichloroisocyanurate (5, 10, 20, 30, 40, 50 and 250 mg l(-1) ) in wash water on transfer of Salmonella Typhimurium from contaminated lettuce to wash water and then to other noncontaminated lettuces washed sequentially in the same water. Experiments were designed mimicking the conditions commonly seen in minimally processed vegetable (MPV) processing plants in Brazil. The scenarios were as follows: (1) Washing one inoculated lettuce portion in nonchlorinated water, followed by washing 10 noninoculated portions sequentially. (2) Washing one inoculated lettuce portion in chlorinated water followed by washing five noninoculated portions sequentially. (3) Washing five inoculated lettuce portions in chlorinated water sequentially, followed by washing five noninoculated portions sequentially. (4) Washing five noninoculated lettuce portions in chlorinated water sequentially, followed by washing five inoculated portions sequentially and then by washing five noninoculated portions sequentially in the same water. Salm. Typhimurium transfer from inoculated lettuce to wash water and further dissemination to noninoculated lettuces occurred when nonchlorinated water was used (scenario 1). When chlorinated water was used (scenarios 2, 3 and 4), no measurable Salm. Typhimurium transfer occurred if the sanitizer was ≥10 mg l(-1) . Use of sanitizers in correct concentrations is important to minimize the risk of microbial transfer during MPV washing. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, the impact of sodium dichloroisocyanurate in the wash water on transfer of Salmonella Typhimurium from inoculated lettuce to wash water and then to other noninoculated lettuces washed sequentially in the same water was evaluated. The use of chlorinated water, at concentration above 10 mg l(-1) , effectively prevented Salm. Typhimurium transfer under several different washing scenarios. Conversely, when nonchlorinated water was used, Salm. Typhimurium transfer occurred in up to at least 10 noninoculated batches of lettuce washed sequentially in the same water.