Bacterial growth, effect production

Application of phenyllactic acid (PLA) in the reduction of fungal mass in food is more desirable compared to other preservatives commonly used in bakery products, such as propionic acid and propionic salts. PLA concentrations effective against fungi from bakery products are usually lower than those required for inhibitory activity. Required concentrations have been reported as L. monocytogenes, 13 mg/ml S. aureus, E. coli, Aeromonas hydrophila, 20 mg/ml, whereas at pH 4 a concentration of < 7.5 mg/ml is enough to inhibit > 50% of bacterial growth (Lavermicocca, Valerio, and Visconti, 2003). 

Cisplatin (Fig. 6.13) is a very useful antitumour agent for the treatment of testicular and ovarian tumours. Its discovery was fortuitous in the extreme, arising from research carried out to investigate the effects of an electric current on bacterial growth. During these experiments, it was discovered that bacterial cell division was inhibited. Further research led to the discovery that an electrolysis product from the platinum electrodes was responsible for the inhibition and the agent was eventually identified as ds-diamino platinum dichloride, known as cisplatin. 

In the USA, water fluoridation became widely available after 1955 and fluoridated toothpastes after 1975 and caries in adolescent children has decreased by 66%. The effects of fluoride on caries are topical from the surface to the interior. Water fluoridation ensures small amounts of fluoride throughout a tooth and fluoridated toothpaste enhances the fluoride concentration at the tooth surface. Protection from caries by artificial fluoridation of water supplies and fluoridated toothpaste is cumulative. Investigations as to how fluoridation protects from caries has identified three mechanisms of caries protection (1) inhibition of demineralization, (2) enhancement of remineralization, and (3) inhibition of bacterial enolase activity reducing lactate production from ingested carbohydrates. Fluoride has little effect on bacterial growth, and gives no direct protection from gingivitis, periodontitis, or osteoporosis... 

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