Microbiological aspects of type C pasteurized milk marketed in the cariri region of the State of Ceará

The quality of milk is directly linked to a reduced number of deteriorating microorganisms, low somatic cell count and absence of pathogens. Therefore, the objective of this study was to evaluate the microbiological quality of type C pasteurized milk, marketed in the Cariri region, in the state of Ceará. The Most Probable Number (MPN) of Coliforms at 45°C and the presence of Salmonella spp were determined, according to the limits established by the Resolution of the Collegiate Board (RCD) number 12, 02/2001. 33 samples of pasteurized type C milk sold in commercial establishments, including supermarkets and bakeries, were collected in different cities in the state of Ceará. The results showed that 39.40%, equivalent to 13 of the samples, were outside the standards established by the current legislation regarding the coliform count at 45°C. Regarding the analysis of Salmonella spp. all samples showed absence of the microorganism.


Introduction
Milk is a food product obtained by complete and interrupted milking of medium and large ruminant animals, rested, healthy and well fed (Brasil, 2011). Presents essential nutrients such as vitamins, minerals and proteins of high biological value (Magan et al. 2020;Mandrioli et al. 2020;Poulsen et al. 2015). Development, v. 9, n. 10, e4199108661, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8661 4 According to Fusco and Quero (2014), milk presents ideal conditions for the development of desirable and undesirable microorganisms, due to its constituents, being an excellent substrate for bacterial proliferation. For this reason, the microbiological quality of milk must be constantly monitored, in order to provide a quality product, reducing losses and free of toxicity (Afriat et al. 2020).
According to Berhe et al. (2020), sensory changes and microbiological growth in milk can be minimized by carrying out practical hygiene and sanitation measures at the milking site and during milk handling, using clean containers and utensils, as well as temperature suitable for transport and storage. Atasever et al. (2020) certified that the control of the food chain must be monitored to ensure that the food does not present any complications to public health, therefore, monitoring the quality of milk hygiene is necessary in order to avoid the growth of undesirable microorganisms.
When preserving pasteurized milk, the maximum temperature limits must be met, since milk after pasteurization must be stored in a cold room and shipped at up to 4,0°C, and for delivery to consumption, the temperature limit must be respected. maximum 7,0°C (Brasil, 2018). Pasteurized milk can be classified according to its type, as: type A, B and C milk.
Type C milk is obtained mechanically or manually, in different herds, does not undergo refrigeration on the farm and is sent in appropriate tanks, direct to the processing industry until 10 am on the day of obtaining it (Brasil, 2002).
The chemical composition, physical-chemical and hygienic characteristics of milk are important parameters for its quality, being recommended by the Ministry of Agriculture, Livestock and Supply, of Normative Instruction 76/2018. Brazilian law establishes minimum and maximum values for bacterial counting, which is allowed in pasteurized milk, thus, the standards that advocate the hygienic-sanitary quality of milk evaluate its microbiological aspect, with the objective of improving its sensory characteristics, since the it can be consumed in its fresh form or added as an ingredient for the production of other products (Brasil, 2018).
Several studies available in the literature have confirmed the presence of microorganisms in quantities above the levels of acceptability of Brazilian legislation, since type C milk has a high degree of contamination, due to some factors such as inadequate processing and / or post-processing recontamination, handling inadequate, poor hygiene of the manipulator and / or process line and failure to implement good manufacturing practices (Santiago et al. 2011;Moura, 2012;Fonseca et al. 2016;Rodrigues and Ferreira, 2016;Santos et al. 2017;Lopes et al. 2018;Pereira et al. 2019) Research, Society and Development, v. 9, n. 10, e4199108661, 2020(CC BY 4.0) | ISSN 2525 5 Therefore, it is assumed that pasteurized milk is a food suitable for consumption, without any risk of contamination by pathogenic bacteria and with its sensory characteristics preserved. The objective of this study was to evaluate the microbiological quality of type C pasteurized milk, sold in the Cariri region, in the state of Ceará.

Material and Methods
Samples of type C pasteurized milk sold in commercial establishments, including For analysis of coliforms at 45 ° C, successive dilutions of the samples were prepared in lactated broth that were incubated in a bacteriological oven at 35 ° C for 48 hours, to verify the gas production. From the tubes with gas production, a handle was transferred to tubes containing bright green broth 2% lactose bile, being incubated at 35 ° C for 48 hours. After that time, gas was produced in the tubes and an elevation of the positive tubes was transferred to the Escherichia coli broth, incubated in a water bath at 44.5 ° C for 24 hours. The result was considered as positive if the tubes had gas in the Durhan tube. Next, together with the Most Probable Number (MPN) table, the MPN of total coliforms per mL of sample was determined.
In the research of Salmonella spp. a 25g portion of the sample was added to 225 mL of the lactated broth and incubated at 35°C for 24 hours. After the incubation time, the sample was placed in tubes containing tetrathionate broth, selenite-cystine broth and Rappaport-Vassiliadis broth and incubated at 42-43°C for 24 hours. After the incubation period, differential plating was performed by streaking with a nickel loop in the selective media: Brilliant Green Agar, Xylose Lysine, Hektoen Enteric Agar and Salmonella-Shigella Agar, incubated at 35-37 ° C for 24 hours. After the incubation period of the differential plating, the biochemical test was carried out, transferring the colonies with the aid of a platinum needle Research, Society and Development, v. 9, n. 10, e4199108661, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8661 6 and inoculation by pricking and streaking in the inclined tubes with the following means: A Lysine Iron agar and Triple Iron Sugar Agar. Finally, incubated at 35-37 ºC for 24 hours, and later, it was observed whether there was a typical Salmonella reaction.

Results and Discussion
The results obtained in the microbiological analyzes of the 33 milk samples are shown in Table I. In the microbiological analysis for coliform count at 45 ºC, the results obtained were It should be noted that thermotolerant coliforms are hygienic-sanitary indicators, therefore, it is essential to observe and respect good manufacturing practices in order to guarantee product safety. They are microorganisms that live in symbiosis with many warm-blooded animals such as oxen, cats, pigs as well as humans (Menezes et al. 2014).
Research, Society and Development, v. 9, n. 10, e4199108661, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8661 Research carried out by Lopes et al. (2018) where they analyzed the count of thermotolerant coliforms in pasteurized milk, it was found that there was no contamination by these microorganisms in any sample of pasteurized milk. Conversely, Rodrigues and Ferreira (2016) found that 80% of the milk samples evaluated were contaminated by coliforms at 45°C. In view of the impact that these contaminations can generate on health, it is of fundamental importance to adopt public policies aimed at training producers and distributors, with regard to care with milk handling. Actions aimed at hygienic-sanitary care throughout the process are essential to guarantee product quality (Santos et al. 2019). Guido et al. (2010) highlighted the importance of GMP's when developing a study with producers in the municipality of Barbosa Ferraz -PR, where they verified through microbiological analysis a reduction in the level of contamination after the insertion of training on good production practices. However, these same authors stressed that it is essential to provide assistance after training, considering that there is a period of adaptation, until all recommendations are followed in a certain and safe way (Lopes et al.

2018).
The research for Salmonella spp showed that all samples analyzed did not contain the presence of this bacterium, where the current legislation establishes a standard of absence Research, Society and Development, v. 9, n. 10, e4199108661, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8661 9 in 25 g, being classified, in this parameter, as "products acceptable for consumption as for microbiological analysis" (Brasil, 2001).
Discordant results to those of the present study were obtained in the research for Salmonella spp., In which 25% of the pasteurized milk samples analyzed obtained a positive result, which was confirmed through biochemical tests (Santos et al. 2019). Moura (2012) analyzing 90 milk samples provided by the Ceará state government program, found that 14.1% of the samples were contaminated by Salmonella spp. Teixeira et al. (2014) found that 100% (n = 20) of the samples evaluated in the study did not present the presence of Salmonella spp.
The shipment of pasteurized milk must be carried out at a maximum temperature of 4°C, by means of its adequate packaging, and taken to the retail trade through vehicles equipped with thermal insulation and equipped with a refrigeration unit, to reach points of sale with a temperature not exceeding 7°C (Brasil, 2018). The result identified through the temperature averages of this study, showed that only 9% (n = 3) samples were below the value allowed by Normative Instruction number 76 of 2018, where a maximum value of 7°C is recommended. Thus, most samples were at inadequate temperatures (91%) at the collection site, which represents a risk to consumers' health.

Conclusion
Type C pasteurized milk has great economic and nutritional value for the Brazilian market, but through the results of the present study, it was found that there are still irregularities in the techniques performed in the processing performed with these products.
The results suggest the need for actions aimed at improving microbiological quality and the adequate processing of milk, stricter hygiene practices, in addition to compliance with good manufacturing practices in order to ensure greater quality and safety of the final product. In view of this, it is verified the importance of an efficient heat treatment in order to eliminate most of the pathogenic and deteriorating microorganisms.