A facility which produced turkey franks that had been microbiologically linked to a case of human listeriosis was evaluated to establish prevalence of contamination and identify potential points for intervention. Listeria monocytogenes was isolated from only two of 41 environmental samples obtained in the plant. Among production line product samples analyzed by the Centers for Disease Control, 0 to 8% of samples from the production stages before the peeler-conveyor belt apparatus were positive for the case strain of L. monocytogenes, whereas 12 of 14 (86%) samples collected from this apparatus were positive (p <0.001). The most probable number (MPN) of L. monocytogenes in finished product purchased from a retail outlet was less than 0.3 per gram; however, the opened package of franks from the case patient's refrigerator had an MPN of >1100 per gram. These data suggest that systematic culturing and analysis of products and production facilities may help identify appropriate interventions to reduce L. monocytogenes contamination in food processing plants and contribute to control of L. monocytogenes in ready-to-eat meat products.

Approximately 800 fresh and frozen meat and poultry samples collected at the point of slaughter were analyzed for Campylobacter jejuni. C. jejuni and C. coli isolates were never discriminated. Isolation levels of C. jejuni from fresh tissues were 5-fold higher (12.1%) than those from frozen tissues (2.3%). The prevalence of C. jejuni in fresh tissues was also higher when results were compared by animal species rather than by individual tissues.

The incidence of salmonella in turkeys from experimental salmonella-controlled and uncontrolled, or normal, flocks processed at three turkey slaughter plants were compared. The results indicate that processing salmonella-controlled turkeys in a plant that routinely kills normal birds may result in the contamination of the salmonella-controlled birds, probably due to salmonella in the plant environment. The salmonella-controlled turkeys studied tended to have a lower incidence of salmonella than normal birds. These observation indicate that salmonella control practices in turkey raising can result in a salmonella reduction in market birds even under existing commercial slaughter, evisceration, and cooling procedures.

An analysis of intracellular and extracellular leptospiral enzymes was made by use of starch-gel electrophoresis with natural and synthetic substrates. Of 37 serotypes examined for extracellular exterase, all had activity of varying mobility and degree. All extracellular preparations were negative for catalase, phosphatase, and naphthylamidase. Intracellularly, five serotypes were examined, including Leptospira biflexa Patoc I, L. biflexa Waz, L. canicola Moulton, L. icterohaemorrhagiae RGA, and L. pomona S91. Among the enzymes detected by this electrophoretic technique were transaminase and catalase, confirming the results of previous investigators. Further, other enzymes heretofore unreported have been detected. These include esterases, phosphatases, lactic, malic, glutamic, succinic, a-glycerophosphate, and 6-phosphogluconic dehydrogenases, and a naphthylamidase. The presence of these enzymes suggests the existence of tricarboxylic acid, glycolytic, and pentose-related pathways in Leptospira. In addition, enzyme patterns show promise in leptospiral classification. Recent investigations have established the presence of the following enzymes in leptospires: catalase (14, 35), oxidase (13, 20), transaminase (27), and lipase (2, 23, 32). Phosphatase activity was determined by Dymowska and Zakrzewska (9) in culture filtrates of leptospires grown in Korthoff's medium, and results were equivocal. This study was concerned with a broad examination of leptospiral enzymes to (i) gain insight into metabolic sequences, (ii) relate enzyme patterns to classification and taxonomy as has been done for other bacteria (3, 25, 31), and (iii) look for enzymatic differences between avirulent and virulent serotypes of leptospires. MATERIALS AND METHODS Cultures. In this study, 37 strains of leptospires were used (Table 1). All were grown initially in Stuart's (38) medium supplemented with 10% rabbit serum and 0.15% agar. Prior to enzymatic studies, all cultures were grown for two transfers in albumin-Tween 80 liquid medium (10, 11). Before mass cultivation procedures were initiated, the cultures were washed and used as the inocula for extracellular and intracellular enzyme studies. Extracellular enzyme preparation. Cell-free culture 'This is a portion of a dissertation submitted by Stanley S. Green to the faculty of the University of Missouri Graduate School in partial fulfillment of the requirements for the Ph.D. degree in Micro

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