Milk. Enumeration of colony-forming units of psychrotrophic microorganisms. Colony-count technique at 6,5°C

2015 ◽  
Keyword(s):  
Colony Count ◽  
Colony Forming Units

scholarly journals Antimicrobial Efficacy of Silver Nanoparticles Incorporated in an Orthodontic Adhesive: An Animal Study

2020 ◽  
Author(s):  
Abbas Bahador ◽  
Baharnaz Ayatollahi ◽  
Azam Akhavan ◽  
Maryam Pourhajibagher ◽  
Mohammad Javad Kharazifard ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Colony Count ◽  
Antimicrobial Efficacy ◽  
Control Group ◽  
Central Incisor ◽  
Minimum Concentration ◽  
Colony Forming Units ◽  
Male Wistar Rats ◽  
Dose Dependent ◽  
One Way Anova

Objectives: This study assessed the antimicrobial efficacy of silver nanoparticles (AgNPs) incorporated in Transbond XT orthodontic adhesive used in rats. Materials and Methods: Transbond XT orthodontic adhesive containing 0%, 1%, 5% and 10% AgNPs was experimentally produced. Twenty-eight male Wistar rats were randomly divided into four groups (n=7) of control (0% AgNPs), 1% AgNPs, 5% AgNPs and 10% AgNPs. After anesthetizing the rats, one drop (10 μm) of the adhesive was applied on the central incisor, and light-cured for 20 s. Transbond XT composite (1×1×1 mm) was also applied. Another 10-μm drop was applied over it, and light-cured for 40 s. Biofilm test was carried out, and the number of colony forming units (CFUs) of Streptococcus sanguinis (S. sanguinis), Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in the saliva of rats was counted at baseline and 24 h after the application of adhesive. The data were analyzed using one-way ANOVA and Tukey’s test. Results: In presence of 5% and 10% AgNPs, S. sanguinis and L. acidophilus counts were significantly lower than those in the control and 1% AgNP groups (P<0.05). The S. mutans colony count was significantly lower in presence of all concentrations of AgNPs compared with the control group (P<0.05). The S. mutans colony count in 10% AgNP group was significantly lower than that in 1% and 5% AgNP groups (P<0.05). Conclusion: Silver nanoparticles have dose-dependent antimicrobial effects; 5% concentration is the minimum concentration of AGNPs with optimal antimicrobial efficacy against all strains evaluated in this study.

The pyruvate test for monitoring the bacteriological quality of raw silo tank milk

1981 ◽  
Vol 48 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Christina M. Cousins ◽  
Ubaldina M. Rodrigues ◽  
Rosemary J. Fulford
Keyword(s):  
Colony Count ◽  
Confidence Limits ◽  
Bacteriological Quality ◽  
Significant Relationships ◽  
Colony Forming Units ◽  
Bacterial Content

SummarySamples of milk from silo tanks were stored at refrigeration temperatures and examined at intervals for pyruvate content and total colony count. Significant relationships between pyruvate, μg/ml, and log colony forming units (cfu)/ml were established for samples stored at 2°C for 2, 3 and 4 d (3, 4 and 5 d of age respectively) but at 5 and 7°C the relationships after 2-d storage (3 d of age) were not significant. From an overall relationship it was predicted that 4 μg pyruvate/ml would correspond to a bacterial content of 3·7 x 106cfu/ml with 95% confidence limits of 6·6 x 10 cfu/ml. 2·1 x 107cfu/ml.

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