RELATION of BACTERIAL DESTRUCTION to CHEMICAL MARKER FORMATION DURING PROCESSING BY THERMAL PULSES1

This paper presents a formulation in dimensionless terms of the equations pertaining to first-order processes that follow Arrhenius kinetics, and applies them to problems in food thermoprocessing. the need for it arose from attempts to understand the relation between destruction of pathogenic microorganisms and formation of chemical markers in the food. During processing food is subjected to a thermal pulse that affects the markers and microorganisms. the dimensionless formulation makes it convenient to obtain equations expressing the relation between the decadic reduction in microbial population and the rise in marker concentration for temperature-time profiles of forms hitherto not conveniently calculable. Measurements of chemical markers can be used with these formulas to predict destruction of microorganisms. Examples are given of calculations demonstrating the feasibility of this approach when a single marker is monitored.     

CHLORINATED HYDROCARBON TISSUE RESIDUES FROM BOVINE FEED SUPPLEMENTS: APPLE POMACE AND FISH MEAL

Beef cattle were fed corn silage with or without apple pomace andlor fish meal. Trace levels of dicofol, an acaricide used on apples, were found in tissues of animals fed apple pomace. Detectable levels of p, p'-DDE were also found in tissues of these cattle since dicofol, as formulated, contains about 2.5% p, p'-DDT. The addition of fish meal containing traces of p,p'-DDE to the ration did not consistently increase p, p'-DDE concentrations since this supplement only comprised 3% of the diet. The corn silage and fish meal each contained trace concentrations of polychlorinated biphenyls (PCBs) but PCBs were not detectable in tissues of any of the cattle.     

Crystal Structure and Defects of Ordered (Pb1-xCax)TiO3

Crystal structure and defects of ordered ((Pb_{1- x} Ca _x )TiO₃ ceramics have been investigated by transmission electron microscopy. The structure is determined to be tetragonal, belonging to point group 4 mm . Pb and Ca are in an ordered fcc arrangement on the A sites. In addition to the chemical ordering, there is ordering due to atomic shuffling or what has been referred to as electrical ordering. Two distinct sets of planar defects are observed in the same region. One set of planar defects are identified as antiphase boundaries that are the results of chemical ordering and the other set are displacement boundaries that are the results of electrical ordering.     

Cellulose Supplementation of A Nutritionally Complete, Liquid Formula Diet: Effect on Gastrointestinal Tract Function of Humans and Fecal Fiber Recovery

The objective was to determine the effect of cellulose supplementation of a nutritionally complete, liquid formula diet on fecal fiber composition, cellulose digestion, and gastrointestinal tract motility in healthy human adults. The liquid formula product was supplemented with 0, 20, 30 or 40g cellulose/subject/day. Dry fecal weights increased with increasing levels of cellulose; however, moisture content of wet stools tended to decrease. Approximately 76% of the cellulose supplements were recovered in the stools as cellulose. While fecal transit times tended to decrease and number of defecations per period tended to increase with increasing levels of cellulose, stools at high levels of cellulose were abnormal in appearance and several subjects experienced problems with elimination.