Chemicals and lemon essential oil effect on Alicyclobacillus acidoterrestris viability

Alicyclobacillus acidoterrestris is considered to be one of the important target microorganisms in the quality control of acidic canned foods. There is an urgent need to develop a suitable method for inhibiting or controlling the germination and outgrowth of A.acidoterrestris in acidic drinks. The aim of this work was to evaluate the chemicals used in the lemon industry (sodium benzoate, potassium sorbate), and lemon essential oil as a natural compound, against a strain of A.acidoterrestris in MEB medium and in lemon juice concentrate. The results pointed out that sodium benzoate (500-1000-2000 ppm) and lemon essential oil (0.08- 0.12- 0.16%) completely inhibited the germination of A. acidoterrestris spores in MEB medium and LJC for 11 days. Potassium sorbate (600-1200 ppm) was more effective to inhibit the growth of the microbial target in lemon juice than in MEB medium. The effect of sodium benzoate, potassium sorbate and essential oil was sporostatic in MEB and LJC as they did not affect spore viability.

Microbial killing activity of peracetic acid.

In vitro killing activity of peracetic acid (Perasafe) at a concentration of 0.26 per cent w/v was tested against Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Salmonella paratyphi A, Acinetobacter baumannii, Sternotrophomonas maltophilia, Enterococcus faecium, Enterococcus faecalis, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis spore, Mycobacterium tuberculosis and human immuno-deficiency virus type I. Exposure to Peracetic acid (0.26% w/v) for 10 minutes resulted in massive killing of all the aforementioned organisms and spore.

O uso de esporos de bacillus subtilis ATCC 19659 para avaliar a eficiência do hipoclorito de sódio 2: a açäo do hipoclorito de sódio sobre lotes de esporos produzidos em tempos diferentes / The use of spores of bacillus subtilis ATCC 19659 to evaluate the efficiency of sodium hypochlorite: the accion of sodium hypochlorite on spores produced in different times

A açäo esporicida do hipoclorito de sódio foi avaliada usando-se Bacillus subtilis ATCC 19659. Lotes de esporos produzidos em épocas diferentes näo apresentaram diferenças significativas (P < 0,5) quanto à sua resistencia a hipoclorito de sódio (105 mg/l de cloro residual livre) em pH 9,8 a 30-C nos tempos de contacto de 30, 60, 90, 120, 140, 160 e 180 minutos. A partir dos números de reduçöes decimais chegou-se a equaçäo de regressäo linear simples, Y=0,0351 - 2,073 (r2 de 0,95 e P < 0,05), onde Y representa número de reduçöes decimais e X o tempo de contacto sosanificante com os esporos. Dessa equaçäo obteve-se o tempo de início de morte (tempo necessário para completar-se a fase "lag") e o valor D, parâmetros importantes para se avaliar a açäo do cloro sobre esporos