Abstract Soymilk was produced from vegetable soybean and fermented by probiotics (Lactobacillus acidophilus La-5, Bifidobacterium animalis Bb-12) in co-culture with Streptococcus thermophilus. The composition of the fermented beverage and oligosaccharides content were determined. The effect of fructooligosaccharides and inulin on the fermentation time and viability of probiotic microorganisms throughout 28 days of storage at 5 °C were evaluated. The soymilk from vegetable soybeans was fermented in just 3.2 h, when pH reached 4.8. Fermentation reduced the contents of stachyose and raffinose in soymilk. Prebiotics had no effect on acidification rate and on viability of B. animalis and S. thermophilus in the fermented beverage. The viable counts of B. animalis Bb-12 remained above 108 CFU mL-1 in the fermented soymilk during 28 days of storage at 5 °C while L. acidophilus La-5 was decreased by 1 log CFU mL-1. The fermented soymilk from vegetable soybeans showed to be a good food matrix to deliver probiotic bacteria, as well as a soy product with a lower content of non-digestible oligosaccharides.
Subject(s)Beverages/analysis , Soy Milk/metabolism , Streptococcus thermophilus/metabolism , Synbiotics , Bifidobacterium animalis/metabolism , Lactobacillus acidophilus/metabolism , Oligosaccharides/analysis , Temperature , Colony Count, Microbial , Soy Milk/isolation & purification , Streptococcus thermophilus/growth & development , Microbial Viability/drug effects , Microbial Viability/radiation effects , Fermentation , Bifidobacterium animalis/growth & development , Hydrogen-Ion Concentration , Inulin/analysis , Lactobacillus acidophilus/growth & development
This study aimed to evaluate the effectiveness of natural casing treatment with nisin and phosphoric acid on control of spoilage microorganisms in vacuum packaged sausages. Ovine casings were dipped in the following baths: 1) 0.1 percent food grade phosphoric acid; 2) 5.0 mg/L nisin; 3) 0.1 percent phosphoric acid and 5.0 mg/L nisin; and 4) sterile water (control). The sausages were produced in a pilot plant, stuffed into the pretreated natural casings, vacuum packaged and stored at 4 and 10 °C for 56 days. The experiments were performed according to a full factorial design 2³, totalizing 8 treatments that were repeated in 3 blocks. Aerobic plate counts and lactic acid bacteria analysis were conducted at 1, 14, 28, 42 and 56 days of storage. Treatment of casings with phosphoric acid 0.1 percent alone did not inhibit the growth of lactic acid bacteria and reduced the aerobic plate count by 1 log. The activity of nisin against lactic acid bacteria was enhanced by the addition of phosphoric acid, demonstrating a synergistic effect. Furthermore nisin activity was more evident at lower storage temperature (4 ºC). Therefore treatment of the natural casings with nisin and phosphoric acid, combined with low storage temperature, are obstacles that present a potential for controlling the growth of lactic acid bacteria in vacuum packaged sausage.
The efficiency of a commercial peracetic acid sanitizer on destruction of Staphylococcus aureus and Escherichia coli was evaluated using two distinct methods. The first method is the AOAC suspension test and the second is a method proposed by one of the authors in which the microbial cells are settled on a stainless steel surface and then treated with the sanitizer. The results showed that when in suspension S. aureus was more resistant to the sanitizer than E. coli. When S. aureus was settled on the stainless steel surface, the contact time between the sanitizer and the microorganisms to attain a 6.5 log reduction in the number of viable cells was three times greater than when the cells were in suspension.
Subject(s)Escherichia coli , Food Contamination , Peracetic Acid , Staphylococcus aureus , Food Industry , Stainless Steel
O ácido peracético é um sanificante com crescente utilizaçäo nas cervejarias do Brasil. Entretanto, pouco se sabe sobre a eficiência desse sanificante sobre os microrganismos contaminantes mais frequentemente encontrados nessas indústrias. Este estudo foi desenvolvido em duas partes: a primeira, realizada nas adegas de pressäo de uma grande cervejaria com sistema CIP (clean-in-place) de limpeza e sanificaçäo, e a segunda parte, foi realizada em laboratório, com os microrganismos contaminantes já isolados e adequadamente identificados. Nas adegas de pressäo, verificou-se que a eficiência do ácido peracético depende do tempo de contato com os microrganismos. Na faixa entre 138 mg/L e 138 mg/L, näo houve diferença na eficiência do ácido peracético...