TY - JOUR TI - Effects of Selected Food Additives on Growth of Pseudomonas fragi AU - Hassan, H. Moustafa AU - Collins, E.B. T2 - Journal of Dairy Science AB - Abstract Tests were made of inhibition of Pseudomonas fragi in lactose-yeast extract broth by the food additives chlortctraeycline, nisin, bacitracin, chloramphenicol, lysozyme, ethylenediaminetetraacetic acid (EDTA), nitrofurazone, propyl-p-hydroxybenzoate, sodium benzoate, and potassium sorbate. The additives that proved effective in broth were tested in skimmilk and half-and-half. Nisin, bacitracin, lysozyme, and nitrofurazone were ineffective in broth; chloramphenicol increased the lag period prior to development of turbidity but resulted in chloramphenicol-resistant populations; and EDTA inhibited the organism slightly in broth but not in skimmilk or half-and-half. Propyl-p-hydroxybenzoate, chlortetracycline, and a mixture of lysozyme and EDTA were effective in broth but not in skimmilk or half-and-half, a difference attributed to metal ions in dairy products that react with chlortetracycline and EDTA. Sodium benzoate retarded P. fragi in broth, but only at low pH. Potassium sorbate was ineffective at pH 6.5 in broth, but at pH 5.5 and 5.2 inhibited growth of P. fragi in broth, skimmilk, and half-and-half. DA - 1969/3// PY - 1969/3// DO - 10.3168/jds.s0022-0302(69)86557-4 VL - 52 IS - 3 SP - 335–340 SN - 0022-0302 UR - http://dx.doi.org/10.3168/jds.s0022-0302(69)86557-4 ER - TY - JOUR TI - Sensory and Shelf-Life Evaluations of Cottage Cheese Treated with Potassium Sorbate AU - Collins, E.B. AU - Hassan, H. Moustafa T2 - Journal of Dairy Science AB - Abstract Cottage cheese samples containing 0.025 to 0.20% potassium sorbate were evaluated by as ensory panel of 18 judges, using the duo-trio test method or organoleptically in seven Cottage cheese plants. The samples were then stored at 4 or 7 C and evaluated for shelf-life. The panel did not significantly detect 0.10% or less of potassium sorbate in Cottage cheese by taste or odor. The minimum levels of potassium sorbate detected in the Cottage cheese plants were 0.10% (four plants), 0.05% (two plants), and 0.025% (one plant). Shelf-life was extended in some experiments by 0.05% potassium sorbate and in all experiments by 0.10%. These amounts of potassium sorbate retarded growth of bacteria that produced fruity and putrid odors and slime in Cottage cheese at refrigeration temperatures and bacteria that produced sourness and molds. DA - 1969/4// PY - 1969/4// DO - 10.3168/jds.s0022-0302(69)86584-7 VL - 52 IS - 4 SP - 439–442 SN - 0022-0302 UR - http://dx.doi.org/10.3168/jds.s0022-0302(69)86584-7 ER - TY - JOUR TI - Molar Growth Yield of Streptococcus faecalis on Pyruvate AU - Hassan, H. Moustafa AU - Collins, E. B. T2 - Journal of Bacteriology AB - Y(pyruvate) was 17.3, similar to Y(arginine), for Streptococcus faecalis 6783 grown statically in a complex medium in 1 atm of air. DA - 1969/3// PY - 1969/3// DO - 10.1128/jb.97.3.1496-1497.1969 VL - 97 IS - 3 SP - 1496–1497 SN - 0021-9193 1098-5530 UR - http://dx.doi.org/10.1128/jb.97.3.1496-1497.1969 ER -