Atividade proteolítica de bactérias psicrotróficas em leites estocados em diferentes temperaturas

Abstract

Proteolytic activity of psychrotrophic bacteria in milk stored at different temperaturesThe widespread use of cooling technology as a tool for maintaining the microbiological and organoleptic characteristics of milk, Without effective hygienic practices throughout the milk production, caused the psychrotrophic micro-organisms to become major deteriorative bacteria in the dairy industry. The present study aimed to assess how the proteolytic psychrotrophic metabolism responds to different milk storage temperatures, drawing a parallel among psychrotrophic growth, amount of micro-organisms capable of breaking down proteins and amount of GMP (glycomacropeptide) released. Milk samples were collected directly from the cooling tank and subjected to count of psychrotrophs, count of proteolytic micro-organisms and the concentration of GMP at different storage times and temperatures. There was no linearity between the microbiological parameters and the GMP measured, according to the time/temperature binomial. The highest concentration of GMP (5.07 mg/mL) was measured in the binomial 8°C/24h (T8/ M24). The data make clear the need for further studies about questions involving the psychrotrophic microbiota in order to clarify extremely important basic questions about their metabolism.

Quality of refrigerated raw milk according to the bulk transport conditions

“…The association between the increase in milk temperature and the increase in SPC is possibly related to milk with higher temperature favors the multiplication of microorganisms, mainly mesophilic. Izidoro, Pereira, Soares, Spina and Pinto (2013) observed that the SPC increased as the temperature and storage time increased in milk stored at different temperatures. The factors formed shown that basic actions such as the proper planning of the collection and transport routes for milk, with shorter and faster routes, good practices in primary production, and technical guidance for the dairy farmers and transporters are essential for good milk quality.…”

Short communication: psychrotrophic microorganism count in raw milk samples preserved with azidiol®

“…The sample storage time did not affect the PMC (p = 0.9012) in milk samples preserved with azidiol ® , while milk samples not added with this preservative showed a linear increase in PMC with progressing time (hours) (p < 0.0001). Izidoro, Pereira, Soares, Spina and Pinto (2013) evaluated the PMC of milk samples at different storage times (12, 24, and 48 hours) and temperatures (4, 8, and 12°C) and concluded that, regardless of the storage temperature, PMC always increased with increasing storage time. Reche et al (2015) observed higher PMC in bulk milk tanks of the model of 'four milkings', and related such results to the higher storage temperature compared to the bulk milk tanks of the model of 'two milkings' since the latter have a greater capacity for faster cooling of milk.…”