Utilização do bioteste com esporos de Bacillus subtilis na avaliação da integridade asseptica de embalagens flexiveis esterilizaveis

AUTOR(ES)
DATA DE PUBLICAÇÃO

1996

RESUMO

The aim of this work was to evaluate the integrity of the top sealing area of retortable pouches formed by a laminate of polypropylene (70 μm), aluminum foil (9um), nylon (15 μm) and polyester (12 μm), using Bacillus subtilis spores as a biotest and also to establish the proper thermal process in order to produce comercially sterile banana puree, packed in pouches processed in a full water-immersion retort. The selected product was banana puree (130g), variety "nanica" (Musa cavendish, Lamb.), pH 4.6 - 4.7, packed in 130 x 170mm retortable pouches. Microholes of different diameters were intentionally made with nickel-chrome threads placed in the top seal area. After sterilization, the threads were withdrawn from the seals and the packages were tested using the spore test. A suspension of B. subtilis spores was aseptically left on the top seal for 1 hour. The capacity of the spores to penetrate through different microholes diameters (32, 48, 79 and 97 μm) was evaluated. The biotest was carried out before and after processing the banana puree at 115°C. Bacillus subtilis penetration and growth was confirmed by biochemical tests and subculture in nutrient agar after incubation of the pouches at 30°C for 7 days. The tested packages were, latter, submitted to eletrolitic test for microholes confirmation. The proper thermal process for banana puree, previously bleached (97°C for 5 min.), was 7,5 min. at 115°C equivalent to an Fo of 0,64 min., confirmed by the general method evaluation and commercial sterility tests. It was noted that heat processing favored the penetration of spores at lower microholes sizes:while the spore test detected microholes of >= 79 μm with 87,5% of penetration before processing, the same test detected penetrations through microholes >= 48 μm with 53,8% penetration after processing. Eletrolitic test was only able to detect microholes formed with 79 μm diameter threads, showing presence of microholes in 69,23% of the tested samples. No penetration was detected in pouches with microholes formed with 32um tested before or after heat processing.

ASSUNTO(S)

bioteste bacillus subtilis

ACESSO AO ARTIGO

Documentos Relacionados