The objective of this work was to evaluate the effect of different water pressures and concentrations of lactic acid on microbial counts (mesophilic bacteria, enterobacteria and Salmonella) on pig carcasses without contamination and contaminated carcasses, before and after the last shower and before being cooled. The tests were carried out using 4, 3 and 2 bar water pressure, and 2, 1 and 0% lactic acid concentration. In general, both the pressure in the shower and lactic acid had a positive effect by reducing the microbial count. The interaction between the pressure and lactic acid caused the largest reduction in carcasses surface count for mesophiles. With regard to enterobacteria on contaminated carcasses, the most important variable was the lactic acid concentration and in uncontaminated carcasses, it was water pressure. The use of 8 bar pressure of the wash water without lactic acid caused a reduction in mesophilic bacteria and enterobacteria, for both the contaminated and uncontaminated carcasses, with results statistically equal to each other, and significantly lower than the initial counts. The water pressure at 8 bar reduced the percentage of carcasses with Salmonella in contaminated carcasses.

O resfriamento rápido de carcaças é um dos aspectos de grande importância para a qualidade final da carne suína. Com o objetivo de diminuir a quebra de peso, foram realizados dois experimentos em carcaças suínas, que foram acompanhadas durante 20 horas por meio da determinação das principais variáveis envolvidas durante dois diferentes processos de resfriamento (padrão utilizado e outro proposto), sendo elas: temperatura, umidade relativa (UR) e velocidade do ar. No experimento I "padrão", as carcaças foram submetidas à utilização de um sistema de choque térmico (duas horas em túnel estático a - 25 °C) e, posteriormente, transportadas à câmara de equalização. Para o experimento II "proposto", as carcaças também foram submetidas ao choque térmico, porém, conduzidas a câmara com UR entre 80% e 85%. As câmaras analisadas em ambos os experimentos não apresentaram alteração nas variáveis: temperatura interna de 5°C e velocidade do ar de aproximadamente 0,3 m/s entre as carcaças. Porém, analisou-se a UR das três câmaras e constatou-se uma grande variabilidade entre os dados, em consequência disso, quantificaram-se altos índices de quebra de peso em cada câmara. No experimento II, houve aumento da UR, reduzindo a quebra de peso das carcaças.

The carcass fast freezing is one of the aspects of great prominence to the final quality of pork. In order to reduce weight loss, two experiments were performed, in which the carcasses were monitored during 20 hours to evaluate the main variables involved during two different freezing processes (standard and proposed) as follows: microbiological quality, storage temperature, relative humidity (RH) and air velocity. In experiment I, the carcasses were submitted to a system using heat shock (2 hours in static tunnel at - 25 °C) and subsequently sent to the equalization chamber. In experiment II, the carcasses were submitted to the heat shock and stored in a chamber with RH between 80-85%. The chambers used in both experiments showed no change in the variables studied (internal temperature of 5 °C and air velocity of approximately 0.3 m/s). However, the relative humidity in the three chambers was evaluated and significant differences were found; as a consequence, high levels of weight loss were observed in both chambers In experiment II there was an increase of RH, which reduced the weight loss of the carcasses.