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Enzymatic stability is undoubtedly one of the most important factors in biotechnology. In this sense, the stability of cellulases present in crude extracts of submerged cultures of Bacillus sp. SMIA-2 during freezing at 3 °C and in the presence of additives was studied. Cellulases were stable during storage for 154 days at 3 °C. The activity of avicellase and CMCase was maintained when crude extracts containing the enzymes were incubated in the presence of ethylene glycol (1M), glycerol (1%) and polyethylene glycol (0.01M) for 1 hour at room temperature.

Minas Gerais is a Brazilian state known as the largest cheese producer in Brazil. Minas Artisanal Cheese (MAC) is produced in different regions of this Brazilian state using raw cow milk to which a natural starter culture ("pingo") is added. "Entre Serras" is one of these regions, in which the MAC production had decreased (even stopped) for decades until recently, when artisanal cheeses production has been resurrected. Here, we aimed to gain insights on the bacterial diversity of "Entre Serras" MAC. 16S rRNA gene amplicon sequencing was used to assess the bacterial community in cheeses produced by four farms (A, B, C, and D) over 60 days of ripening. Overall, Lactococcus lactis was the predominant species found, regardless of the producer/farm. Enterococcus, Streptococcus, Lactobacillus and Leuconostoc genera were also prevalent in the samples microbiota and their levels varied according to the producer/farm. Cheeses produced by Farms A and B presented high contaminant levels (mainly Enterobacteriaceae and S. aureus), which may be attributed to poor hygiene during cheese production and/or herd health management. Chao1 indices varied significantly when the estimated species richness values of the producers/farms were compared (p 0.05). A principal coordinate analysis also revealed distinct microbial communities for some farms (p 0.001). However, no statistical significance was identified when samples were grouped by ripening time. Core microbiota analysis indicated that "Entre Serras" MAC microbiota includes not only LAB, but also spoilage and potentially pathogenic bacteria. We provide the first insights on the bacterial diversity of "Entre Serras" MAC, helping the understanding of the inter-regional microbiological diversity of the samples.

A implementação de medidas preventivas de contaminações do leite com bactérias esporuladas é imprescindível considerando que esses microrganismos são produtores de enzimas proteolíticas e lipolíticas termoresistentes associadas a problemas tecnológicos como off flavors, coagulação doce e gosto amargo em leite e derivados, dentre outros. Dentre essas medidas, pode-se citar tipo de sanitizante e as condições de uso como concentração, tempo de contato e temperatura. Objetivou-se avaliar a eficiência de sanitizantes comumente empregados na indústria de laticínios sobre bactérias esporuladas isoladas de leite UHT. Empregou-se o teste de suspensão para avaliar a eficiência de soluções de hipoclorito de sódio, biguanida, ácido peracético e peróxido de hidrogênio sobre 18 estirpes de bactérias esporuladas do gênero Bacillus isoladas de leite UHT integral. Embora a maior ação sanitizante tenha sido observada para a biguanida, nenhum dos sanitizantes foi efetivo nas condições avaliadas, considerando que os valores médios observados de redução decimal (RD) foram inferiores a cinco ciclos logarítmicos ou a 99,999%. A efetividade de sanitizantes é um fator primordial para o controle de contaminações de natureza microbiana na indústria de laticínios. Assim, é fundamental a definição das condições ideais de uso destes produtos. It is known that sporulated bacteria produce proteolytic and lipolytic ther­ moresistant enzymes associated with technological problems such as off-flavors, age gelation and bitter taste in milk and dairy products. Preventive measures to avoid contamination of milk must be taken in consideration, e.g., the employment of a certain type of sanitizing agent, its conditions of use, concentration, contact time and temperature. The aim of this work was to evaluate the sanitation efficiency of workers of the dairy industry in relation to sporulated bacteria isolated from UHT milk. The suspension test was used to evaluate the efficiency of solutions of sodium hypocholite, biguanide, peracetic acid and hydrogen peroxide against 18 strains of Bacillus sp. isolated from whole UHT milk. Although the biguanide resulted in significant decimal reduction, none of the sanitizing agents studied was effective under the evaluated conditions. The average decimal reduction values obtained were below 5 log cycles (99.999%). The effectiveness of the sanitizing agent is a primary factor in order to control the contaminations within the dairy industry. Thus, it is essential to define the ideal conditions of use of these agents.

It is known that sporulated bacteria produce proteolytic and lipolytic thermoresistant enzymes associated with technological problems such as off-flavors, age gelation and bitter taste in milk and dairy products. Preventive measures to avoid contamination of milk must be taken in consideration, e.g., the employment of a certain type of sanitizing agent, its conditions of use, concentration, contact time and temperature. The aim of this work was to evaluate the sanitation efficiency of workers of the dairy industry in relation to sporulated bacteria isolated from UHT milk. The suspension test was used to evaluate the efficiency of solutions of sodium hypocholite, biguanide, peracetic acid and hydrogen peroxide against 18 strains of Bacillus sp. isolated from whole UHT milk. Although the biguanide resulted in significant decimal reduction, none of the sanitizing agents studied was effective under the evaluated conditions. The average decimal reduction values obtained were below 5 log cycles (99.999%). The effectiveness of the sanitizing agent is a primary factor in order to control the contaminations within the dairy industry. Thus, it is essential to define the ideal conditions of use of these agents. A implementação de medidas preventivas de contaminações do leite com bactérias esporuladas é imprescindível considerando que esses microrganismos são produtores de enzimas proteolíticas e lipolíticas termoresistentes associadas a problemas tecnológicos como off flavors, coagulação doce e gosto amargo em leite e derivados, dentre outros. Dentre essas medidas, pode-se citar tipo de sanitizante e as condições de uso como concentração, tempo de contato e temperatura. Objetivou-se avaliar a eficiência de sanitizantes comumente empregados na indústria de laticínios sobre bactérias esporuladas isoladas de leite UHT. Empregou-se o teste de suspensão para avaliar a eficiência de soluções de hipoclorito de sódio, biguanida, ácido peracético e peróxido de hidrogênio sobre 18 estirpes de bactérias esporuladas do gênero Bacillus isoladas de leite UHT integral. Embora a maior ação sanitizante tenha sido observada para a biguanida, nenhum dos sanitizantes foi efetivo nas condições avaliadas, considerando que os valores médios observados de redução decimal (RD) foram inferiores a cinco ciclos logarítmicos ou a 99,999%. A efetividade de sanitizantes é um fator primordial para o controle de contaminações de natureza microbiana na indústria de laticínios. Assim, é fundamental a definição das condições ideais de uso destes produtos.