Immersion heat treatments for inactivation of Salmonella enteritidis with intact eggs.

The effects of water-bath immersion heat treatments on the inactivation of Salmonella enteritidis within intact shell eggs were evaluated. Six pooled strains of Salm. enteritidis (ca 3 x 10(8) cfu, inoculated near the centre of the yolk) were completely inactivated within 50-57.5 min at a bath temperature of 58 degrees C and within 65-75 min at 57 degrees C (an 8.4 to 8.5-D process per egg). Following the initial 24 to 35-min come-up period, semilogarithmic survivor curves obtained at 58 and 57 degrees C yielded apparent decimal reduction times (D-values) of 4.5 and 6.0 min, respectively. Haugh unit values increased during heating, while yolk index and albumen pH values were unaffected. Albumen clarity and functionality were affected by the thermal treatments; therefore, extended whip times would be required for meringue preparation using immersion-heated egg whites. Immersion-heated shell eggs could provide Salmonella-free ingredients for the preparation of a variety of minimally-cooked foods of interest to consumers and foodservice operators.

Introduction to egg pasteurization.

The science of microbiology is very young in comparison with the age of mankind. Related developments in the area of pasteurization have been made during the past 131 yr. This symposium reveals some recent advancements in pasteurization of shell eggs and egg products.

Dates and date pits as ingredients in broiler starting and coturnix quail breeder diets.

Two broiler growth and two quail breeder studies were conducted to evaluate the dietary potential of dates, date meat, and date pits. The test ingredients were incorporated in broiler starting diets at levels ranging from 8 to 43% dates, 16 to 43% date meat, and 5 to 27% date pits. The quail breeder diet had ingredient ranges of 10 to 30% dates, 8 to 24% date meat, and 5 to 15% date pits. The date ingredient diets supported broiler weights and feed conversions comparable to or better than the control diet. Quail breeder feed consumption decreased at the 30% date level; however in the second trial 24% dates supported normal intake. Egg production and egg weight on all date and date part diets were equal to those of the control.

Effect of inorganic phosphate source and dietary phosphorus level on laying hen performance and eggshell quality.

Two experiments were conducted to evaluate laying hen performance when fed two sources of inorganic phosphorus. In Experiment 1, a regular and a coarse form of defluorinated phosphate and one source of dicalcium phosphate were used in diets calculated to contain either .4 or .5% total phosphorus (.2 or .3% nonphytate phosphorus). In Experiment 2, either the regular form of defluorinated phosphate or the dicalcium phosphate source was fed in diets calculated to contain either .4, .5, .6, or .7% total phosphorus (.2, .3, .4, or .5% nonphytate phosphorus). In Experiment 1, hens fed .5% total dietary phosphorus consumed more feed and produced heavier eggs (P less than or equal to .05). Hens fed the .4% dietary phosphorus level lost more weight during the experiment (P less than or equal to .05). No differences among dietary treatments existed for egg specific gravity. A significant source by level interaction occurred for the farm classification of thin-shelled, cracked, or broken eggs and for the total of these classifications. In Experiment 2, egg production, feed consumption, egg weight, and egg mass were depressed (P less than or equal to .05) at the .4% total dietary phosphorus level. Hens fed the .4 and .7% total dietary phosphorus level laid eggs with the highest and lowest egg specific gravity, respectively. This trend was inverse to the effect of these phosphorus levels on egg weights. A significant source by level interaction occurred for the farm classification of thin shell and for the total percentage of eggs with exterior defects. At the .4% total phosphorus level, the regular form of defluorinated phosphate produced eggs with a significantly greater thin shell classification than the dicalcium phosphate source. Hens fed the dicalcium phosphate source produced a higher percentage of compressed-sided and misshapen eggs.

Influence of wet and dry feed on laying hens under heat stress.

Two experiments were carried out with a split-plot design over time using White Leghorn hens, 161 days of age. The experiments were conducted to determine the effect of two ambient temperatures (21.1 versus 29.4 C in Experiment 1 and 21.1 versus 33.3 C in Experiment 2) on feed and water consumption using four dietary regimens. The day was divided into two feeding periods: a.m. (0600 to 1300 h) and p.m. (1300 to 0600 h the next morning). The four regimens were as follows: dry feed during both a.m. and p.m. periods; dry feed during a.m. period and wet feed (50% moisture) during the p.m. period; wet feed in the a.m. and dry feed in the p.m.; and wet feet during both a.m. and p.m. periods. The hens were maintained on a 14 h light: 10 h dark lighting program. The hens consumed the greatest quantity of DM and water during the p.m. period, regardless of the environmental temperature to which the hens were exposed. Constant heat stress at 29.4 and 33.3 increased (P less than or equal to .05) drinking water intake during the a.m. but not during the p.m. period. The use of wet feed and dry-wet feed provided a 38 and 48% increase (P less than or equal to .05), respectively, in DM intake when compared with the use of dry feed at 33.3 C. Exposure of laying hens to high environmental temperatures (29.4 and 33.3 C) decreased (P less than or equal to .05) albumen and shell weight; yolk weight was depressed only at 33.3 C. The use of wet feed (50% moisture), ad libitum, or in the p.m. stimulated DM intake at 33.3 C.

A new in-cage treatment system for control of northern fowl mites on laying hens.

Commercially available plastic and other types of flexible tubing were tested to determine their relative permeability to an emulsifiable concentrate (EC) of permethrin acaricide. Bioassays employing northern fowl mites, Ornithonyssus sylviarum (Canestrini and Fanzago), indicated that .3 mg permethrin/cm2 surface area penetrated vinyl plastic tubing that had been filled with 42.5% active ingredient EC for 14 days. Vinyl tubing circuits were installed in wire poultry cages, either in the form of suspended loops or woven through the rear cage wall, and permethrin EC was introduced by means of a small pump. Significant reductions in northern fowl mite populations on hens caged therein were apparent after 48 days posttreatment. This approach has merit as a long-term, labor-economical form of mite control on caged poultry.

Comparative efficacy of plastic strips impregnated with permethrin and permethrin dust for northern fowl mite control on caged laying hens.

Established populations of northern fowl mites, Ornitonyssus sylviarum (Canestrini and Fanzago), on caged laying hens were effectively controlled within 77 days by application of two plastic strips impregnated with permethrin per cage. Such strips contained 9.6% active ingredient (wt/wt), were ca. 20.5-cm long, and were affixed to the top cage wires. Use of only one strip per cage resulted in less control, approximating that obtained with .25% permethrin dust. Egg mass, expressed as gram egg per hen per day, was significantly greater in all treated groups.

Application phenomena and efficacy of concentrated acaricide dusts for northern fowl mite control on caged laying hens.

Fluorescent pigments were used to measure plumage coverage when caged laying hens were dusted for northern fowl mite, Ornithonyssus sylviarum (Canestrini and Fanzago), control. Carriage type electrostatic or high velocity backpack equipment produced superior coverage 2 hr posttreatment when the rates of 454 g (1 lb) dust per 100 or 500 hens was employed. A redistribution of dust was noted 48 hr posttreatment, and a subsequent experiment demonstrated that this phenomenon resulted from intracage cross contamination dependent upon bird caging density. Carbaryl 80% wettable powder (WP) at 454 g/1600 hens and tetrachlorvinphos 50% WP at 454 g/1000 hens provided northern fowl mite control for 11 and 5 weeks posttreatment, respectively.

Comparative evaluation of four registered acaricides for field control of northern fowl mites on caged laying hens.

Carbaryl and tetrachlorvinphos provided longer lasting control of northern fowl mites, Ornithonyssus sylviarum (Canestrini and Fanzago), than did coumaphos or malathion when the materials were applied to caged laying hens as aqueous sprays. The average duration of residual control was ca. 5 weeks for carbaryl, 4.3 weeks for tetrachlorvinphos, 3.5 weeks for coumaphos, and 2 weeks for malathion. No presumptive evidence of northern fowl mite resistance to carbaryl or tetrachlorvinphos was encountered. In contrast, malathion often failed to produce satisfactory control, and difficulty with adequate dispersion of coumaphos wettable powder was noted.