RESUMO
Antibiotic resistance of 44 lactic starter culture strains currently used by the dairy industry has been examined in Mueller- Hinton medium, supplemented with glucose (5 g/L) and yeast extract (5 g/L), by the agar disk diffusion assay. Results with various classes of antibiotics used to treat cattle mastitis indicated that lactococcal cultures should be diluted 20% and incubated at 30°C for 16 to 18 h in this medium for reliable results. The degree of antibiotic susceptibility was compared to standards established by the National Committee for Clinical Laboratory Standards. The procedure outlined in the present study is recommended as a routine method for testing antibiotic resistance of lactococci. This represents a more logical drug sensitivity approach than the use of noncheese starter bacteria to test for antibiotics in milk.
RESUMO
Top round cuts were obtained from sixteen sides of utility cows. Eight sides were randomly assigned as control (CON) and the remainders were prerigor pressurized (PRP) at 15,000 psi for 2 min. The top round from each side was divided into 4 wholesale cuts, vacuum packaged, heat-shrunk and randomly assigned to 0, 3, 5 or 7 weeks of storage at -1.6±1°C. Upon completion of each storage interval, wholesale cuts were removed from the storage area, purge losses determined and samples for microbial counts obtained. Two boneless steaks were prepared from each wholesale cut and displayed for 5 d at 1-3°C with 1076 lux fluorescent lighting for 12 h each day. Purge loss differed (P<0.05) only for the 5th week of storage. Wholesale cuts from PRP and CON had similar microbial counts at 0 and 3 weeks, while CON samples had higher microbial counts at 5 and 7 weeks. For all storage intervals, muscle color of the displayed steaks was improved (P<0.05) for the first 4 d of the display period by the PRP treatment. PRP steaks were consistently less discolored for all storage intervals. PRP improved the overall desirability of the displayed steaks throughout the experiment. Steaks prepared from PRP and CON wholesale cuts had the same microbial counts at 0 and 3 weeks of storage while CON steaks had higher and in most instances significantly higher microbial counts for 5 and 7 weeks. PRP had no apparant detrimental effects on the storage or display-life characteristics of meat, instead it beneficially influenced most of the parameters that were examined in this experiment.
RESUMO
Agglutinins that cause clumping and settling of lactic streptococci are reviewed. Evidence defining the role played by agglutinins in sedimentation defects occurring during cottage cheese manufacture is presented. The needs for a fast, simple and reliable agglutination test, and additional research on the influence of agglutinins on other fermented milk products, are noted.
RESUMO
Despite the opinion of many scientists and laymen that lactobacilli benefit adult intestinal health, the medical and scientific communities do not accept this as fact. This paper offers possible beneficial and detrimental roles which lactobacilli could play; relevant literature citations also are made. Healthful roles include those exerted as a result of their presence as members of the intestinal flora as well as their benefits as culture or enzyme preparations. Speculative detrimental effects discussed are nutrient competition, carcinogen activation and detoxification interference (glucuronide hydrolysis).
