Rheological properties and microstructure of Cheddar cheese made with different fat contents.

Reduced- and low-fat cheeses are desired based on composition but often fall short on overall quality. One of the major problems with fat reduction in cheese is the development of a firm texture that does not break down during mastication, unlike that observed in full-fat cheeses. The objective of this investigation was to determine how the amount of fat affects the structure of Cheddar cheese from initial formation (2 wk) through 24 wk of aging. Cheeses were made with target fat contents of 3 to 33% (wt/wt) and moisture to protein ratios of 1.5:1. This allowed for comparisons based on relative amounts of fat and protein gel phases. Cheese microstructure was determined by confocal scanning laser microscopy combined with quantitative image analysis. Rheological analysis was used to determine changes in mechanical properties. Increasing fat content caused an increase in size of fat globules and a higher percentage of nonspherical globules. However, no changes in fat globules were observed with aging. Cheese rigidity (storage modulus) increased with fat content at 10°C, but differences attributable to fat were not apparent at 25°C. This was attributable to the storage modulus of fat approaching that of the protein gel; therefore, the amount of fat or gel phase did not have an effect on the cheese storage modulus. The rigidity of cheese decreased with storage and, because changes in the fat phase were not detected, it appeared to be attributable to changes in the gel network. It appeared that the diminished textural quality in low-fat Cheddar cheese is attributed to changes in the breakdown pattern during chewing, as altered by fat disrupting the cheese network.

Diagnostic peritoneal lavage in blunt trauma patients with coagulopathy.

Coagulopathies such as dilutional coagulopathy secondary to massive crystalloid and/or blood resuscitation, and disseminated intravascular coagulation secondary to head injury, complicate the care of severely traumatized patients. The accuracy of diagnostic peritoneal lavage has not been appraised in patients with coagulopathy. During a 3-year period, 847 patients underwent diagnostic peritoneal lavage using the direct visualization, open method. Exploratory laparotomy was performed on 298 patients for a positive diagnostic peritoneal lavage. All patients had coagulation studies prior to diagnostic peritoneal lavage. Twenty-eight patients (9.4%) with a mean injury severity score of 45, had coagulopathy prior to diagnostic peritoneal lavage. Only 2% (6/298) of the diagnostic peritoneal lavages were falsely positive despite the presence of pelvic fractures in 24.5% (73/298) of the patients. The incidence of falsely positive diagnostic peritoneal lavage was similar (P = .5) for patients with coagulopathy (3.6%, 1/28) as compared to patients without coagulopathy (1.8%, 5/272). Following blunt trauma, clinical indications for diagnostic peritoneal lavage do not mandate coagulation screening because diagnostic peritoneal lavage is reliable in patients with preexisting coagulopathy.