Effect of sanitization on minimally processed cabbage ( Brassica oleracea L . )

The aim of this study was to evaluate the effect of sanitization on minimally processed cabbage (Brassica oleracea L.). This is a quantitative, descriptive and laboratorial study where the samples were submitted to three different processes: washing only in running water; washing in running water followed by the use of sodium hypochlorite-based sanitizer and, finally, washing in running water followed by sanitization using chlorinated compounds based on sodium dichloroisocyanurate. Subsequently, microbiological analyses of total coliforms Escherichia coli and Salmonella ssp. were performed. The results showed that the sodium hypochlorite-based solution did not present a reduction in microbial population, while those based on sodium dichloroisocyanurate allowed the reduction to safe levels for human consumption. A greater control in sodium hypochlorite-based products is suggested, since possibly this result was due to the low concentration of free active chlorine.


Abstract
The aim of this study was to evaluate the effect of sanitization on minimally processed cabbage (Brassica oleracea L.). This is a quantitative, descriptive and laboratorial study where the samples were submitted to three different processes: washing only in running water; washing in running water followed by the use of sodium hypochlorite-based sanitizer and, finally, washing in running water followed by sanitization using chlorinated compounds based on sodium dichloroisocyanurate. Subsequently, microbiological analyses of total coliforms Escherichia coli and Salmonella ssp. were performed. The results showed that the sodium hypochlorite-based solution did not present a reduction in microbial population, while those based on sodium dichloroisocyanurate allowed the reduction to safe levels for human consumption. A greater control in sodium hypochlorite-based products is suggested, since possibly this result was due to the low concentration of free active chlorine.

Introduction
The consumption of vegetables, mainly in the minimally processed form, such as cabbage, has been significantly grown as a factor justified by nutritional benefits and, mainly, convenience/practicality, considering these foods are most often sold and/or ready for consumption (Santos et al., 2019).
Corresponding to the accelerated growth in the consumption of minimally processed food, there is also an increase in the number of people affected by foodborne diseases, widely known as FBD's. Thus, it requires the correct application of sanitization procedures, since they present a high rate of contamination by various microorganisms, generally related to the intake of such products (Saraiva et al., 2019;Santos et al., 2017).
The sanitization of vegetables is essential to ensure microbiological quality, since this process aims to eliminate pathogenic microorganisms and reduce the deterioration, to levels considered as safe. These adopted processes should be, in addition to being effective, safe by the toxicological point of view (Silva, 2018).
Regarding the ability to reduce microorganism populations by the use of sanitizers, as there are variations related to the physicochemical characteristics of foods that are submitted to this process. In addition, the contact time, type of microorganism and concentration directly influence the inhibitory effect. Therefore, it is of fundamental importance the use of antimicrobials that have proven efficacy against microorganisms, such as Escherichia coli, in the recommended contact time and dilution (Brasil, 2016). Research, Society and Development, v. 9, n. 6, e59963467, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i6.3467 4 Among the chemical compounds used in the food sanitization process, iodinated compounds, peracetic acid, quaternary ammonium, chlorinated compounds, and others can be listed. The chlorinated compounds, which are the most used by their relative cheaper cost, act quickly and in low concentrations, easy to apply and have a wide spectrum of action.
However, because of their instability, the storage should occur in dark packages, properly closed, in ventilated places and protected from light (Germano & Germano, 2015;Nunes et al., 2010).
Chlorinated compounds are classified into two categories: organic and inorganic.
Inorganic chlorinated compounds are: sodium hypochlorite, calcium hypochlorite and lithium hypochlorite, chlorine gas and chlorine dioxide. Organic compounds, on the other hand, are represented by: chloramine T, dicloramine T, dichloro dimethyl hydantoin, trichloroisocyanuric acid and dichloroisocyanuric acid (Germano & Germano, 2015). Nunes et al. (2010) ensure that chlorinated compounds in their different forms, such as sodium hypochlorite (inorganic), sodium dichloroisocyanurate (organic), are widely used in the process of sanitization of food, at the household and industrial level. These compounds act by denaturation of proteins of the microbial cellular membrane, causing their death.
Considering the importance of the sanitization process to ensure the distribution of a microbiologically safe food, it is necessary to maintain constant vigilance about food safety.
In this sense, the study was conducted with the aim of evaluating the effect of sanitization in minimally processed cabbage (Brassica oleracea L.).

Material and Methods
This is a study of the type: quantitative, descriptive and laboratorial. The procedure was performed at the Food Microbiology Laboratory of the State University of Southwest of Bahia, with samples of vegetables (minimally processed cabbage) obtained at a fair in Vitória da Conquista -Bahia, Brazil.
The samples were submitted to three different treatments: washing only in running water (Treatment A); washing in running water followed by the use of sodium hypochloritebased household sanitizer (Treatment B) and, finally, washing in running water followed by sanitization using chlorinated compounds based on powdered sodium dichloroisocyanurate (NaDCC) (Treatment C), commonly used in institutional restaurants. The prepared solutions Research, Society and Development, v. 9, n. 6, e59963467, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i6.3467 5 and the time of contact with the sanitized food, followed the descriptions presented on the labels of the products. Subsequently, microbiological analyses of total coliforms, E. coli and Salmonella ssp. were performed, according to the parameters recommended by Normative Instruction no. 60 (Brasil, 2019).
Initially, serial dilution was performed, using 25g of the minimally processed cabbage samples in 225 ml of 0.1% peptonized water, thus the first dilution (10 -1 ) which after homogenization, 1 ml of the first dilution was transferred to 9 ml of peptonized water, subsequently forming 10 -2 and 10 -3 dilutions by the same method.
For the analyses of total coliforms, thermotolerant coliforms (E. coli), and Salmonella ssp., the procedures described by the American Public Health Association (2001)

Results and Discussion
The results of microbiological analyses comparing the efficacy of sanitization are presented in table 1. In the analyses of the results presented in Table 1, regarding total coliforms, an important effect was observed in the reduction of such microorganism populations, when comparing Treatment C with Treatment A. This result was expected, since sodium dichloroisocyanurate is a product with a high concentration of active chlorine, which contributes to the reduction of microbial population (Germano & Germano, 2015).
Comparing the results of Treatment B with the other treatments, it was found that it had no effect, since the counting of these microorganisms were higher than those present in the samples that were only washed in running water (Treatment A).
Regarding the E. coli counting test, the Normative Instruction no. 60 (Brasil, 2019), which revokes the Resolution of the Collegiate Board (RDC) no. 12/2001 (Brasil, 2001), presents as reference values of 102 MPN/g for fresh vegetables, in natura and 10 MPN/g for foods undergoing sanitization. As presented in the previous table, it can be observed that the cabbage sanitized with sanitary water in a solution indicated by the product label for application in food, it was not efficient, and the values were higher until the cabbage was washed in running water.
The objective of sanitization is to reduce the microorganism population to safe levels, in other words, this reduction must be within the values recommended by the Normative Instruction to ensure the safety of food, however, it was observed that in treatment B (sodium hypochlorite) was not able to reduce total coliforms and neither E. coli.
This result can be explained by the low concentration of active chlorine in the product. Regarding the analysis of presence of Salmonella spp, it was observed that all samples were in consonance with the standards recommended by Normative Instruction no. 60 (Brasil, 2019), which recommend the absence in fresh in natura vegetables, as well as, for those that are submitted to a sanitization process. Development, v. 9, n. 6, e59963467, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i6.3467 7 Further studies are needed to analyze the efficiency of other household sanitizer brands based on sodium hypochlorite to investigate whether it is a problem in a specific brand or it occurs also in others.

Conclusion
The chlorinated compound based on sodium hypochlorite did not presented the expected efficacy. Therefore, it is suggested that these products should be evaluated for the presence of active chlorine, to ensure, thus, the sanitizing action predicted by the product, since it is widely used for cleaning at household level.
In regard to sodium dichloroisocyanurate, it was found that it was effective in relation to microbial action, which can ensure the consumer a food free of contamination and, consequently, reducing the risk of foodborne diseases.
As a suggestion of future studies, it is indicated to evaluate the effect of other sanitizers based on sodium hypochlorite in other minimally processed vegetables. In addition, the quantification of active chlorine by different methodologies.