Validity and reliability of the Bristol Stool Form Scale in healthy adults and patients with diarrhoea-predominant irritable bowel syndrome.

BACKGROUND: The Bristol Stool Form Scale (BSFS) is a 7-point scale used extensively in clinical practice and research for stool form measurement, which has undergone limited validity and reliability testing. AIM: To determine the validity and reliability of the BSFS in measuring stool form in healthy adults and patients with diarrhoea-predominant irritable bowel syndrome (IBS-D). METHODS: One hundred and sixty-nine healthy volunteers provided a stool sample and used the BSFS to classify stool form, which was compared with measured stool water content and with values from 19 patients with IBS-D. Eighty-six volunteers used the BSFS to classify 26 stool models to determine accuracy and reliability. RESULTS: Volunteers' classifications of stool type correlated with stool water (Spearman's rho = 0.491, P < 0.001), which increased in hard (Types 1-2), normal (Types 3-5) and loose stools (Types 6-7) (P < 0.001). The BSFS detected differences in stool form between healthy volunteers (mean 3.7, s.d. 1.5) and IBS-D patients (mean 5.0, s.d. 1.2) (P < 0.001). Overall, 977/1204 (81%) stool models were correctly classified (substantial accuracy, κ = 0.78), although <80% of Types 2, 3, 5 and 6 were classified correctly. On 852/1118 (76%) occasions, volunteers classified covert duplicate models to the same stool type (substantial reliability, κ = 0.72), but with only moderate reliability for Types 2 (63%, κ = 0.57) and 3 (62%, κ = 0.55). CONCLUSIONS: The BSFS demonstrated substantial validity and reliability, although difficulties arose around clinical decision points (Types 2, 3, 5, 6) that warrant investigation in larger clinical populations. Potential for improving validity and reliability through modifications to the BSFS or training in its use should be explored.

Immunomagnetic detection of Bacillus stearothermophilus spores in food and environmental samples.

There are currently no methods for the rapid and sensitive detection of bacterial spores that could be used to direct raw materials containing high spore loads away from products that pose a food safety risk. Existing methods require an overnight incubation, cannot detect spores below 10(5) CFU/ml, or are not specific to particular species. This work describes a method to specifically detect < 10(4) CFU of bacterial spores per ml within 2 h. Polyclonal antibodies to Bacillus stearothermophilus spores were attached to 2.8-micron-diameter magnetic polystyrene beads by using a polythreonine cross-linker via the antibody carbohydrate moiety. A biotin-avidin-amplified sandwich enzyme-linked immunosorbent assay coupled to a fluorescent substrate was used to quantitate captured spores. The concentration of B. stearothermophilus spores in samples was linearly correlated to fluorescent activity (r2 = 0.99) with a lower detection limit of 8 x 10(3) CFU/ml and an upper detection limit of 8 x 10(5) CFU/ml. The detection limits are not fixed and can be changed by varying the immunomagnetic bead concentration. Several food and environmental samples were tested to demonstrate the versatility of the assay.

Sensory and Microbial Quality of Milk Processed for Extended Shelf Life by Direct Steam Injection †.

Heat treatments of milk between 100 and 145°C produce a new type of product with a shelf life of 15 to 30 days at 7°C, which is termed extended shelf life (ESL) milk. Little information is available on the safety and sensory qualities of this product. Extended shelf life milk is being processed commercially to expand the distribution area of fluid milk products. After arrival at market, this product still has the shelf life of a pasteurized product. In this study milk was processed by direct steam injection at temperatures between 100 and 140°C for 4 or 12 s. Holding time did not significantly affect the sensory quality of the milk. A trained taste panel found cooked flavor and other off flavors varied significantly with increasing processing temperature and storage time. There were no significant differences noted in cooked or off flavors between 132 and 140°C. Psychrotrophic Bacillus species were isolated from milk processed at and below 132°C, while no organisms were isolated from milk processed at temperatures at or above 134°C. Consumer preference panels indicated consumers preferred milk processed at 134°C for 4 s to ultrahigh-temperature (UHT) processed milk, although there was a slight preference for high-temperature short-time processed (HTST) milk compared to milk processed at 134°C for 4 s. Higher temperatures had a less destructive effect on lipase activity, while storage time did not significantly affect lipase activity.