| The microbiological effects of 0.5% poly- and pyrophosphates were studied in laboratory media and in fresh or cooked, vacuum packaged bratwurst-type sausage held under refrigeration (5(DEGREES)C) and subsequent elevated temperatures (24-25(DEGREES)C). Tetrasodium pyrophosphate (TSPP), heated or unheated, was most inhibitory to selected bacteria in laboratory media, while sodium tripolyphosphate (STPP) and sodium polyphosphate glassy (SPG) lost their antimicrobial properties upon heating and sodium acid pyrophosphate (SAPP) was ineffective. Although phosphate addition consistently resulted in lower bacterial numbers, none of the phosphates exhibited significant (P < 0.05) antimicrobial activity in cooked or uncooked sausage stored at 5(DEGREES)C for 7 days. 0.5% SAPP and combinations of 0.5% SAPP and 100 ppm NaNO(,2) were highly inhibitory to aerobic (mesophilic and psychrotropic) and anaerobic bacteria, including inoculated Clostridium sporogenes PA 3679, in cooked, vacuum packaged bratwurst under temperature abuse conditions. STPP at a level of 0.5%, alone or combined with 50 ppm NaNO(,2), was also inhibitory to a smaller extent. Hydrolysis and residual levels of SAPP were monitored by adapting a colorimetric method for orthophosphate determination in meats. An apparent relationship between orthophosphate formation and bacterial inhibition by 0.5% SAPP was found in cooked, vacuum packaged bratwurst. Hydrolysis of phosphates in meats and its possible relationship to antimicrobial activity are discussed. STPP or TSPP at a concentration of 0.4% or four phosphate blends had no significant (P > 0.05) antibacterial effects in frozen beef patties held 90 days at -20(DEGREES)C, but inhibited bacterial growth at 24-25(DEGREES)C and significantly (P < 0.05) increased pH, orthophosphate content, palatability and overall acceptability scores of beef patties. |
