Radiotherapy (RT) near salivary glands results in changes in the oral flora in favour of cariogenic organisms and an increased susceptibility to caries. The aim of this study was to assess the effect of a 12-month preventive programme on caries incidence and on the levels of mutans streptococci (ms) and lactobacilli in tongue loop samples taken from patients before, during and after RT. The regime consisted of 2 × daily rinsing with 10 ml 0.2% chlorhexidine, diluted 1:1 with water, for 1 week before RT, during RT and for 4 weeks after RT. This was then substituted with a 0.05% NaF rinse daily. A saliva substitute containing 2 ppm F was used as required. Scaling was carried out before RT and dietary advice and oral hygiene instruction given. Appropriate radiographs were taken at baseline and after 6 and 12 months. Tongue loop samples for microbiology were taken in the middle and end of RT and subsequently at 6,8,12,24, 40 and 52 weeks. Whenever levels of ms exceeded 2× 105 cfu/ml sample, 1% chlorhexidine gel in custom-made applicator trays was applied by the subject for 5 min daily for 14 days. In 25 subjects completing the programme, there was a total of 3 new caries lesions after 12 months. Thirteen pre-existing enamel lesions were arrested. There were significant reductions (p < 0.005) in ms levels from baseline values during RT and 4 weeks after RT. There were no significant increases in ms levels throughout the study. Nineteen of the 25 subjects required at least one course of chlorhexidine gel to maintain this low level of ms. Lactobacilli levels rose steadily after RT and remained high throughout the study. There was a significant improvement in gingival health at 6 months (p < 0.005) and at 12 months (p < 0.05). Mean stimulated whole salivary flow rate was significantly reduced (p < 0.05) after RT; this reduction persisted for 12 weeks and did not return to baseline values at the end of 12 months. It is concluded that the chlorhexidine/fluoride regime used in this study can be recommended for the control of caries in this group of highly susceptible individuals.

SUMMARY –EDTA, in concentrations above 2.5 mM, was found inhibitory to germination of and outgrowth from spores of C. botulinum Type A and to toxin production in a fish homogenate. Inhibitory action was influenced by pH of the medium in the range pH 6.5–8.1, the action increasing with pH. It was influenced by Mg and Ca concentrations in the medium, equimolar concentrations of added CaCl2 or MgCl2, completely erasing the growth inhibitory action. Initial spore concentration also influenced inhibitory efficacy–the higher the spore concentration, the higher the EDTA concentration required for inhibition. There was no evidence that EDTA, in any concentration used, promoted spore germination. Release of Ca, Mg and DPA from incubating spores was suppressed to varying extents by 5.0 and 10 mM EDTA.

A comparison was made between steam canner and other conventional methods of home canning such as boiling water bath and pressure canner at 5 and 10 lb. of pressure. Several heat penetration studies were done and the processes were evaluated using sound thermobacteriological and mathematical basis. Only acid products such as tomato juice, tomatoes and apple sauce, were considered in this investigation. The final process times calculated for the three products and the come‐up time needed for each equipment, indicates that steam canner method may be more efficient than other methods for home canning of acid‐food products.

No abstract

The equilibrium relative humidity isotherm of a cherry beverage base and a strawberry gelatin dessert mix colored with anthocyanins from grape skins, cranberries and roselle was evaluated versus a Red No. 2 control. As well, the water vapor transmission rate of the packaging material was evaluated to evaluate probable shelf-life. Results indicated that physical parameters, such as hygroscopicity, must be considered in estimating effects of the use of natural colorants in foods as well as the color and chemical stability normally investigated.