No abstract

The starter cultures (Lactobacillus pentosus LP1, L. Pentosus olivarum OLIV, L. Plantarum L74, L. Alimentarius BJ33, L. Sake LAD, L. Curvatus LB1, Staphylococcus carnosus MC1, S. Carnosus MIII, S. Carnosus M17, S. Xylosus CM258, S. Xylosus DD34) were kindly provided by the companies Christian Hansen (Horsholm, Denmark), Rudolf Müller (Pohlheim, Germany) and Gewürzmüller (Stuttgart, Germany) in freezedried form. Lactobacilli cultures were grown at 30°C in MRS broth (Oxoid, Basingstoke, England) and staphylococci were grown at 30°C in a broth (designated PM broth) containing tryptone (10 g·L -1 ), yeast extract (5 g·L -1 ) and glucose (1 g·L -1 ) and adjusted to pH 7.2. The suspensions obtained after an overnight incubation were used as inocula for the model system study whereas starter cultures were used directly in freeze-dried form for application to whole fillets processing. Enumeration of bacteria in the model systemThe fish mince slurry was serially diluted in Ringers solution (Oxoid) under aseptic conditions, and used for enumeration of microorganisms by the surface spread plate technique. Lactic acid bacteria (LAB) counts were determined on MRS agar (Oxoid) and staphylococci were enumerated on PM agar (PM broth + 14 g.L -1 ). Microbiological analyses of whole filletsSamples of whole salmon fillets (10g) were aseptically removed and homogenized for 2 min at normal speed in 90 mL of Ringers solution using a Stomacher 400 (Seward Medical, London, England). The homogenate was serially diluted in Ringers solution and used for enumeration of microorganisms. LAB were enumerated on MRS agar, staphylococci were enumerated on PM agar and total bacteria counts were determined on Plate Count Agar (Oxoid) after incubation at 30° for 48 hr for enumeration of enterococci, and at 30°C for 48 hr under anaerobic conditions for detection of clostridia.Presence of Salmonella was assessed following the procedure described in NF ISO 6579 (1900): after enrichment in peptone water overnight and in Rappaport Vasiliadis broth (Oxoid) at 37°C for 24 hr, samples were streaked on Brilliant Green Agar (Oxoid) and plates were incubated at 37°C for 24 hr.Detection of Listeria was also performed (AOAC, 1995) after enrichment in selective broth (Oxoid) at 30°C for 48 hr and streaking on selective Oxford agar (Oxoid) incubated at 37°C for 24 hr. pH measurementIn the model system study, pH was measured following an indirect method: 1.5g of slurry was mixed with 10 mL of distilled water. Readings were taken on a meter pH62 (Radiometer, Copenhagen, Denmark). In whole fillets, pH was measured according to a direct method, using a meter pH 320 (WTW, Weilheim, Germany). Each measurement represents the mean of 3 readings. Formulation of salmon model systemFresh farmed salmon were deheaded, degutted, filleted and stored at 4°C until processed. Samples of salmon flesh (200-300g), free of skin and bones, was homogenized with distilled water (1:1) in a ABSTRACTThe integration of defined starter cultures into a fish fermentation process was studied. Six...

Fermented sausages, inoculated with lipolytic and non lipolytic starter cultures and a control containing glucono-␦-lactone (GDL) and an antibiotic mixture were prepared. The sausages were analyzed on the basis of color, pH, water activity, weight loss, moisture and fat contents. Microbiological analyses were performed to measure total viable counts, lactobacilli and, staphylococci and micrococci. The increase in total and individual free fatty acids, and lipid oxidation was monitored. Results showed no difference (pϾ0.05) in the level of free fatty acids between treatments, indicating that lipolysis was most likely due to endogenous meat enzymes.

As a result of intensification and centralization of poultry slaughtering, the amount of slaughter byproducts produced at a single location is increasing. These byproducts are rich in protein, fat, and vitamins and, therefore, constitute a potentially useful raw material for use as animal feed. To maintain the nutritive value of these byproducts they should be processed to minimize or eliminate degenerative changes that reduce the feed value of the product. In this paper amino acid breakdown in slaughter-fresh poultry viscera, heads, and breast meat is studied as a model. Initial amino acid breakdown in viscera was observed (also when bacterial growth was excluded by gamma-irradiation), which resulted in high levels of total volatile N and cadaverine. Putrescine was produced only in viscera after bacterial proliferation. In heads and breast meat, no production of metabolites of amino acid degradation was observed as a result of initial enzymatic activity. It is concluded that during preservation of poultry byproducts not only bacterial proliferation, but also enzymatic breakdown of amino acids, must be prevented.

Flocculated poultry sludge was mixed with 3% molasses and was flow-therm pasteurized for 5 min at a core temperature of 95 C. The sludge was subsequently cooled to between 20 and 25 C and fermented with Lactobacillus plantarum as starter culture. Three groups of eight 8- to 10-wk-old, individually housed fattening pigs (Hypor) were fed according to a fixed scheme correlated with age. One control group received a restricted ration of commercial compound feed (Group A). The other control group was provided "nearly ad libitum" access to the same commercial compound feed (Group C). The experimental group received the same amount of commercial compound feed as Group A, but the diet was supplemented with fermented sludge, at an inclusion rate of 19 to 28% of the total ration (DM basis). The pigs fed the sludge-containing diet and those receiving the compound pig feed "nearly ad libitum" showed comparable growth results. It was concluded that the net energy (NEpig) level of .68 g DM of sludge was comparable to the NEpig level of 1 g compound pig feed (88% DM). A decrease in colony counts of Enterobacteriaceae in the intestinal tract of the pigs, was regarded as positive, as it might lower the risk of disturbance of the gut flora by enteropathogenic bacteria such as Escherichia coli and Salmonella. No adverse effects on health and performance were observed as a result of the feeding of pasteurized and subsequently fermented flocculated poultry sludge to fattening pigs. It is concluded that this sludge can serve as a valuable feed constituent as long as it is processed properly.