Avaliação da ação de substâncias químicas conservantes na contagem total de bactérias do leite e verificação da capacidade de detecção em diferentes tempos de estocagem de acordo com os métodos qualitativos oficiais de análise

Abstract

By being of nutrients easy to assimilate. The milk becomes an excellent way of culture for the majority of microorganism, having your composition influenced by a range of factors and becoming prone to adulteration. The quality standard of this food must be rigorously controlled in order to ensure a safe product that doesn’t cause any damage to our health. Frauds by adding preservatives substances in the milk have been recurrent in the country due to the fact of being able to inhibited growth or destroy pathogenies microorganisms, this way, the necessity of new methodologies and techniques for a routine analysis is extremely necessary, knowing that, the adulterated milk can, besides causing several economic losses also cause important consequences to the consumer's health. The objective of this project was to verify the influence of the concentration of preservative chemical substances like formaldehyde, hydrogen peroxide and sodium hypochlorite on the total account of bacteria and the capacity of detecting in different storage times based on detection limits obtained by Santos (2019). The analyses were made with commercial samples of residue-free pasteurized milk and adulterated following the parameters: sample 1 containing a concentration below the detection limit; sample 2 that is characterized as LD and at last, sample 3 that represents a concentration above the detection limit; and evaluated for the presence of formaldehyde, hydrogen peroxide and sodium hypochlorite by official methods at times zero, 24 hours and 48 hours under refrigeration from 4°C to 5°C. The obtained results show high percentages of reducing the total amount of bacteria in the milk even in low concentration and mostly after the time of 24 hours. Apart from that it was found that unlike other substances used, hydrogen peroxide degrades itself after a period of 24 hours, what makes even harder to detect it, due to the fact that it is no longer noticeable in milk, however, continues to fulfill its inhibiting function of the microorganism’s proliferation. It is extremely important that the microbiota of milk is known and controlled, since low quality dairy products, making it perishable and a possible spread of disease to human beings can carry several bacteria. The analysis of residues of antimicrobial substances must be carried out frequently and preferably with samples collected directly from the producers' tanks for a better evaluation of fraud occurrences.