Artisanal cachaça and brewer's spent grain as sources of yeasts with promising biotechnological properties.

AIMS: This study aimed to characterize yeasts isolated from the environment of artisanal cachaça production and brewer's spent grain-bearing in mind their further application in bioprocesses. METHODS AND RESULTS: Cell morphology, growth and fermentative parameters, and karyotyping were employed for the selection and grouping of yeast strains. The results showed that from 134 yeast strains studied, 14·2% exhibited cells with snowflake morphology, which is not appropriate for bioethanol production. The fermentation in sugarcane syrup was carried out with 71 Saccharomyces cerevisiae, 19 Torulaspora delbrueckii, eight Wickerhamomyces anomalus, six Candida parapsilosis, five Pichia mashurica, three Candida intermedia, two Clavispora lusitaniae and one Candida aaseri. Among the most important ethanol-producing strains, T. delbrueckii LMQA BSG 7 and S. cerevisiae LMQA SNR 65 presented biomass yield, ethanol yield and productivity similar or higher than PE-2 and CAT-1 (bioethanol industrial strains). CONCLUSIONS: This study showed a high potential for industrial application of the strains LMQA SNR 65 (S. cerevisiae) and LMQA BSG 7 (T. delbrueckii). It was found that the use of the chromosomal profile is not adequate to qualify yeasts concerning their technological performance. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reported yeasts isolated from uncommon sources that present significant characteristics for potential application in bioprocesses.

Sheep Milk: Physicochemical Characteristics and Relevance for Functional Food Development.

Sheep milk has a high nutritional value and high concentrations of proteins, fats, minerals, and vitamins, as compared to the milks of other domestic species. The physicochemical and nutritional characteristics of sheep milk can be advantageous for the manufacture of products containing prebiotic ingredients and/or probiotic bacteria, which are major categories in the functional food market. Following this technological trend, this review will address the characteristics and advantages of sheep milk as a potentially functional food, as well as the development of sheep milk dairy products containing prebiotics and/or probiotics.

Evaluation of a cross contamination model describing transfer of Salmonella spp. and Listeria monocytogenes during grinding of pork and beef.

In a previous study, a model was developed to describe the transfer and survival of Salmonella during grinding of pork (Møller, C.O.A., Nauta, M.J., Christensen, B.B., Dalgaard, P., Hansen, T.B., 2012. Modelling transfer of Salmonella typhimurium DT104 during simulation of grinding of pork. Journal of Applied Microbiology 112 (1), 90-98). The robustness of this model is now evaluated by studying its performance for predicting the transfer and survival of Salmonella spp. and Listeria monocytogenes during grinding of different types of meat (pork and beef), using two different grinders, different sizes and different numbers of pieces of meats to be ground. A total of 19 grinding trials were collected. Acceptable Simulation Zone (ASZ), visual inspection of the data, Quantitative Microbiological Risk Assessment (QMRA), as well as the Total Transfer Potential (TTP) were used as approaches to evaluate model performance and to access the quality of the cross contamination model predictions. Using the ASZ approach and considering that 70% of the observed counts have to be inside a defined acceptable zone of ±0.5 log10CFU per portion, it was found that the cross contamination parameters suggested by Møller et al. (2012) were not able to describe all 19 trials. However, for each of the collected grinding trials, the transfer event was well described when fitted to the model structure proposed by Møller et al. (2012). Parameter estimates obtained by fitting observed trials performed at different conditions, such as size and number of pieces of meat to be ground, may not be applied to describe cross contamination of unlike processing. Nevertheless, the risk estimates, as well as the TTP, revealed that the risk of disease may be reduced when the grinding of meat is performed in a grinder made of stainless steel (for all surfaces in contact with the meat), using a well-sharpened knife and holding at room temperatures lower than 4°C.

Assessing the effect of sodium dichloroisocyanurate concentration on transfer of Salmonella enterica serotype Typhimurium in wash water for production of minimally processed iceberg lettuce (Lactuca sativa L.).

UNLABELLED: This study evaluated the impact of sodium dichloroisocyanurate (5, 10, 20, 30, 40, 50 and 250 mg l(-1) ) in wash water on transfer of Salmonella Typhimurium from contaminated lettuce to wash water and then to other noncontaminated lettuces washed sequentially in the same water. Experiments were designed mimicking the conditions commonly seen in minimally processed vegetable (MPV) processing plants in Brazil. The scenarios were as follows: (1) Washing one inoculated lettuce portion in nonchlorinated water, followed by washing 10 noninoculated portions sequentially. (2) Washing one inoculated lettuce portion in chlorinated water followed by washing five noninoculated portions sequentially. (3) Washing five inoculated lettuce portions in chlorinated water sequentially, followed by washing five noninoculated portions sequentially. (4) Washing five noninoculated lettuce portions in chlorinated water sequentially, followed by washing five inoculated portions sequentially and then by washing five noninoculated portions sequentially in the same water. Salm. Typhimurium transfer from inoculated lettuce to wash water and further dissemination to noninoculated lettuces occurred when nonchlorinated water was used (scenario 1). When chlorinated water was used (scenarios 2, 3 and 4), no measurable Salm. Typhimurium transfer occurred if the sanitizer was ≥10 mg l(-1) . Use of sanitizers in correct concentrations is important to minimize the risk of microbial transfer during MPV washing. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, the impact of sodium dichloroisocyanurate in the wash water on transfer of Salmonella Typhimurium from inoculated lettuce to wash water and then to other noninoculated lettuces washed sequentially in the same water was evaluated. The use of chlorinated water, at concentration above 10 mg l(-1) , effectively prevented Salm. Typhimurium transfer under several different washing scenarios. Conversely, when nonchlorinated water was used, Salm. Typhimurium transfer occurred in up to at least 10 noninoculated batches of lettuce washed sequentially in the same water.

Assessing the growth of Escherichia coli O157:H7 and Salmonella in spinach, lettuce, parsley and chard extracts at different storage temperatures.

AIMS: The objective of this work was to study the growth potential of Escherichia coli O157:H7 and Salmonella spp. in leafy vegetable extracts at different temperature conditions. METHODS AND RESULTS: Cocktails of five strains of E. coli O157:H7 and of Salmonella enterica were used. Inoculated aqueous vegetable extracts were incubated at 8, 10, 16 and 20°C during 21 days. Microbial growth was monitored using Bioscreen C(®) . In spinach extract, results showed that for E. coli O157:H7 and Salmonella significant differences (P < 0·05) for µabs (maximum absorbance rate) were obtained. For both pathogens, growth in chard was slightly lower. In contrast, iceberg lettuce and parsley showed the lowest values of µabs , below 0·008 h(-1) . The coefficients of variance (CoV) calculated for the different replicates evidenced that at low temperature (8°C) a more variable behaviour of both pathogens is expected (CoV > 180%). CONCLUSIONS: This study provides evidence that aqueous extracts from vegetable tissues can result in distinct growth niche producing different response in various types of vegetables. SIGNIFICANCE AND IMPACT OF THE STUDY: Finally, these results can be used as basis to establish risk rankings of pathogens and leafy vegetable matrices with relation to their potential growth.

Assessment of antioxidant activity, lipid profile, general biochemical and immune system responses of Wistar rats fed with dairy dessert containing Lactobacillus acidophilus La-5.

The viability and survival of Lactobacillus acidophilus La5 under in vitro simulated gastrointestinal in probiotic dairy dessert was assessed. In addition, the effects of regular consumption of the dessert (5g/day) on the lipid profile, immune system, and antioxidant/biochemical status of Wistar rats were also evaluated after 2weeks of treatment. Adequate counts of L. acidophilus La-5 were observed regards the viability and gastrointestinal conditions. The probiotic dairy dessert was efficient in reducing the LDL-cholesterol, triacylglycerol and increased the HDL-cholesterol in serum. Aspartate amino transferase, alanine aminotransferase, total protein, albumin, heat shock proteins, immune system responses, and blood-cells counts (monocyte, lymphocyte, neutrophil and leucocyte) were not affected (p>0.05) after 15days of treatment. Overall, the probiotic dairy dessert may be a viable alternative to enhance the blood lipid profile and could be used to improve the antioxidant defenses.

Alicyclobacillus acidoterrestris in pasteurized exotic Brazilian fruit juices: isolation, genotypic characterization and heat resistance.

In this study, the population of Alicyclobacillus spp. was estimated in pasteurized exotic Brazilian fruit juices using the most probable number (MPN) technique followed by biochemical tests. Pasteurized passion fruit (n = 57) and pineapple (n = 50) juices were taken directly from Brazilian manufacturers. While Alicyclobacillus spp. was isolated from passion fruit juice, the microorganism was not found in any pineapple juice samples. A higher incidence of Alicyclobacillus was observed in samples taken in June and July (dry months in Brazil) in comparison to the other months (March, April, May and August), and the highest Alicyclobacillus counts were recovered from these samples(>23 MNP/100 mL). Sixteen (n = 16) Alicyclobacillus strains were typed using the randomly amplified polymorphic DNA method (RAPD-PCR). RAPD-PCR revealed great genetic similarity between the passion fruit juice strains and Alicyclobacillus acidoterrestris DSM 2498. The heat resistance of three isolates was determined, and the mean D(95°) (1.7 min) and z (7.6 °C) values in the passion fruit juice were not significantly different (p > 0.05) from those obtained for the DSM 2498 strain (D(95°) = 1.5 min and z = 7.1 °C). This is the first report on the isolation of A. acidoterrestris from exotic fruit juices such as passion fruit juice. It is worth pointing out the importance of applying good agricultural practices in the field and applying controls for the fruit selection and washing steps, as well as controlling the time/temperature conditions for pasteurization so as to reduce the incidence and chances of A. acidoterrestris spoilage in these juices.

Modelling the lag time and growth rate of Aspergillus section Nigri IOC 4573 in mango nectar as a function of temperature and pH.

AIMS: To assess the behaviour of Aspergillus section Nigri IOC 4573 in mango nectar as affected by temperature and pH. METHODS AND RESULTS: A central composite design (2(2)+2*2+3) was used to estimate the influence of temperature (17·2-22·8°C) and pH (3·28-4·7) on A. section Nigri growth (λ, lag time; µ, growth rate). Secondary models (polynomial and Arrhenius-Davey) describing the effects of temperature and pH on λ and µ were constructed. A decrease in temperature from 22·8°C to 17·2°C resulted in an a 16-fold increase in λ. The increase in temperature from 20°C to 22·8°C at pH=4·0 led to a fourfold increase in µ. The polynomial model was the best in fitting the data and the pH (linear), temperature (linear and quadratic terms) significantly influenced λ. For µ, there was a significant influence by the pH (linear), temperature and pH (quadratic terms). CONCLUSIONS: The storage of mango nectar at <15°C and reduced pH could completely inhibit the growth of A. section Nigri. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to show how storage temperature and seasonal variability (pH) between harvests may affect mould growth in mango nectar.

Heat resistance and the effects of continuous pasteurization on the inactivation of Byssochlamys fulva ascospores in clarified apple juice.

AIMS: To determine thermal resistance, the effect of pasteurization temperature variations (c. 2 degrees C) in a continuous system in the number of decimal reductions (n) of a Byssochlamys strain in clarified apple juice (CAJ). METHODS AND RESULTS: Thermal destruction kinetics of Byssochlamys fulva IOC 4518 in thermal death tubes were determined at 85 degrees , 90 degrees , 92 degrees and 95 degrees C by using Weibull distribution frequency model. Three processes with different heating and holding temperatures (A: 94 degrees , 92 degrees C; B: 95 degrees , 93 degrees C; C: 96 degrees , 94 degrees C, respectively) were performed in a continuous system. Process time was 30 s. delta (time of first decimal reduction) values were: 42.98, 8.10, 3.62 and 1.81 min. Variable n ranged from 0.16 to >4.78 for process B (equivalent to industrial). Variable n (0.95-2.66 log CFU ml(-1)) were obtained in CAJ bottles processed under condition B, while process A resulted in total heat-resistant mould (HRM) survival and process C in total HRM destruction. CONCLUSIONS: This study demonstrates that small variations in temperature during the CAJ pasteurization could result in elimination or survival of HRM due to its nonlogarithmic behaviour. SIGNIFICANCE AND IMPACT OF THE STUDY: This was the first study to use Weibull frequency method to model inactivation of HRM in fruit juices. Temperature variations could culminate in the presence of HRM in pasteurized juices even when low counts (<10 spores per 100 ml) were present in the raw materials.

Food safety knowledge of cheese consumers.

The aim of this study was to evaluate habits and practices of cheese consumers toward their level of knowledge of food safety. A total of 1000 people were interviewed in several cities of the state of Rio de Janeiro, Brazil. Five hundred thirty-eight (53.8%) people consume cheese daily, while 318 (31.8%) and 144 (14.4%) consume cheese weekly and monthly, respectively. Five hundred twenty-two (52%) people reported its usage as an ingredient used in the preparation of other dishes, while 320 (32%) of the interviewed people consume cheese directly as a part of the diet. Typical Brazilian cheeses such as "Minas Frescal" and "Prato" cheese are preferred by 528 (52.8%) of the consumers. Of the total consumers, 764 (76.4%) purchase cheese from supermarkets, while 236 (23.6%) from open-air markets. Inspected cheese is purchased by 350 (35%) consumers, while 650 (65%) buy it without knowing if they were submitted to previous fiscalization. Four hundred thirty (43%) consumers do not know any disease transmitted by cheese that has not been inspected. Overall, educational campaigns must be developed by the Sanitary Surveillance and the Health Agencies to improve the knowledge of the consumer about food safety of cheeses.