Effect of Heat and High-Pressure Treatments on Microbiological Quality and Immunoglobulin G Stability of Caprine Colostrum

Abstract

Caprine colostrums (6 batches) were subjected to heat (56 degrees C for 60 min and 63 degrees C for 30 min) and high-pressure (400 and 500 MPa for 10 min at 20 degrees C) treatments at laboratory scale, and analyses of the main microbial groups and the extent of IgG denaturation (determined by immunodiffusion) were performed. Overall mean microbial values in raw colostrums were: total count, 5.55 log cfu/mL; Enterobacteriaceae, 2.64 log cfu/mL; lactococci, 5.41 log cfu/mL; lactobacilli, 2.34 log cfu/mL; and enterococci, 4.06 log cfu/mL. Neither Salmonella spp. nor Listeria monocytogenes were detected, whereas coagulase-positive staphylococci were found in various colostrum samples with an overall mean of 1.02 log cfu/mL. Heat and high-pressure treatments significantly reduced total count (1.47 log), lactococci (1.45 log), enterococci (2.47 log), and Enterobacteriaceae, whereas lactobacilli and coagulase-positive staphylococci counts were reduced to undetectable levels, but differences between technological treatments were not statistically significant. High-pressure treatments were as efficient in reducing the bacterial population as were heat pasteurization treatments: 95.50 and 96.93% for pressure treatments of 400 and 500 MPa, and 91.61 and 97.59% for heat treatments of 56 degrees C for 60 min and 63 degrees C for 30 min, respectively. All treatments assayed produced a reduction in colostrum IgG concentration (27.53, 23.58, 23.33, 22.09, and 17.06 mg/mL for raw, heat-treated at 56 degrees C for 60 min or 63 degrees C for 30 min, and pressure-treated at 400 and 500 MPa, respectively), but differences were only observed between raw colostrums and those pressure-treated at 500 MPa. This laboratory-scale study indicated that 20- to 30-mL volumes of goat colostrum could be heated and pressure-treated (400 MPa) to produce hygienic colostrum without affecting IgG concentration.

Effect of high-pressure treatment on denaturation of bovine β-lactoglobulin and α-lactalbumin

“…Conventional immunochemical techniques are particularly useful for detecting conformational changes in proteins with concomitant loss of epitopes as a result of denaturation [25]. This technique has been widely employed to study the denaturation of whey proteins subjected to technological treatments such as heat treatment [23], high-intensity pulse electric fields processing [26], or high-pressure treatment [27]. High correlation coefficients (r 2 [ 0.98) were obtained when representing the square of the diameter of precipitating rings corresponding to protein standards versus their concentration, being the relationship linear within the range from 10 to 250 lg/mL for both proteins.…”

Analysis of denaturation of bovine IgG by heat and high pressure using an optical biosensor

“…Previous studies of Ig stability have also revealed speciesspecific differences in the heat sensitivity of bovine, caprine and ovine IgG (Law, 1995;Trujillo et al, 2007) and between bovine IgG, IgA and IgM isotypes (Mainer et al, 1997). However, few studies have considered differentiation of Fab and Fc domains within bovine lacteal IgG with respect to relative conformational stability, and the potential for other milk components to moderate this stability, and conclusions remain equivocal (Cao et al, 2007;Dominguez et al, 1997Dominguez et al, , 2001Li et al, 2005;Ohnuki & Otani, 2005).…”

The effect of colostrum period management on BW and immune system in lambs: from birth to weaning

“…Each room had central heating (20°C) and 0.3 m 2 floor space per lamb. Lambs were bottle-fed a sheep colostrum pool that was previously pasteurized at 63°C for 30 min according to Trujillo et al (2007). Artificially reared lambs received colostrum amount equivalent to 4 g of IgG/kg of BW at birth (C4 group) or 8 g of IgG/kg of BW at birth (C8 group) divided into three meals at 2, 14 and 24 h after birth.…”