Ninety-four presumptive Micrococcus and Staphylococcus strains isolated from both commercial beef biltong and game biltong, were identified using a scheme based on the system used by Baird-Parker. The changes occurring in both the aerobic, saprophytic microbial flora and the environmental factors, during conversion of beef to biltong, were examined. The predominantly Gram-negative, halo-sensitive flora initially present on the meat, was replaced by Gram-positive, halo-tolerant staphylococci and micrococci, which form the dominant component of the microflora of the final product. This replacement was attributed to changing environmental factors, principally to the increasing sodium chloride concentration and associated decline in water activity. The presence of the antifungal antibiotic, pimaricin, during processing did not influence the bacterial flora of the product. However, the addition of potassium sorbate altered the microbial profile of the product significantly. The presence of these two preservatives, at the concentrations used, could not be detected organoleptically. The importance of the saprophytic microflora of the product ln relation to the environmental factors during processing, is also discussed.

The aim of this study was to evaluate the effect of ultrasound application (US, bath 25 kHz, 500 W) on physical, chemical and microbiological properties of Italian-type fermented sausage during processing and storage. The US was used after mass stuffing in synthetic packaging during 0 min, 3 min, 6 min and 9 min of application. Completely randomized design was adopted (DIC) and the data submitted to analysis of variance (ANOVA) to test the significance of the variables. Further, a Pearson´s correlation analysis was performed and the differences among the averages were calculated by using the Tukey s test (p≤0.05). Some data were subjected to multivariate analysis of variance (MANOVA), complemented by the technique of principal components analysis. The parameters of fermented sausage evaluated included counts of lactic acid bacteria (Pediococcus pentosaceus and Pediococcus acidilactici) and Microccocaceae (Staphylococcus xylosus and Staphylococcus carnosus), aw, pH, color (CIE L * a * b *), lipid oxidation (peroxide value and TBARS ), protein oxidation (thiol), total heme pigments, non-heme iron and metmyoglobin, during processing (days 0, 2, 15 and 28) and along the shelf-life (after 1, 30 and 120 days). Texture parameters (cohesiveness, flexibility, chewiness and hardness) were evaluated in fermented sausages after 90 days of storage and the formation of volatile compounds at the beginning (day 1) and the end of storage (after 120 days). US had a positive effect on the growth of bacteria in some processing steps and storage conditions (p<0.05), especially on Micrococcaceae (Staphylococcus xylosus and Staphylococcus carnosus) with 9 min of US exposure. The pH, aw and color parameters were not significantly affected by the US (p>0.05). The oxidation of lipids and proteins was accelerated with US application, but maintaining acceptable values in the final product. The total heme pigments, non-heme iron and metmyoglobin were affected by sonication (p<0.05) and influenced the oxidative reactions and vice versa. The canonical discriminant analysis separated the samples into groups according to the day of evaluation and not according to the treatments. Therefore, due to the predominant effect of processing time / storage in fermented sausage characteristics a lack of significant effect of sonication time was observed. The US did not significantly affect texture profile parameters (p>0.05), but hardness and chewiness tended to reduce with sonication. Regarding the volatiles were no statistical differences between treatments (p>0.05), except for ethanol and hexanol (p<0.05) at the beginning of storage. The US has affected the growth curve of bacteria, accelerating or inhibiting their growth that some points, and has the potential to be explored in improving the texture and red color formation of fermented sausages. The lack of pronounced effect on US some characteristics was primarily attributable to acoustic parameters adopted, low exposure time to the US, fermented sausage consistency, mass heterogeneity and quantity / fat composition, among other factors. Thus, it is suggested to further studies to assess the potential of using the US as emerging technology in the fermented sausage manufacturing. / O objetivo deste trabalho foi avaliar o efeito do uso de banho de ultrassom (US, 25 kHz, 500 W) sobre características físicas, químicas e microbiológicas de salame tipo Italiano durante seu processamento e no armazenamento. O US foi usado logo após embutimento da massa na tripa durante diferentes tempos de exposição (0 min controle não sonicado, 3 min, 6 min e 9 min). Foi adotado delineamento inteiramente casualizado (DIC) e os dados submetidos à análise de variância univariada (ANOVA) para testar a significância das variáveis. Posteriormente foi feita análise de correlação de Pearson e as diferenças entre as médias calculadas pelo teste de Tukey (p≤0,05). Alguns dados foram sujeitos à análise de variância multivariada (MANOVA), complementada pela técnica de componentes principais. As avaliações realizadas incluíram contagens das bactérias lácticas (Pediococcus pentosaceus e Pediococcus acidilactici) e Microccocaceae (Staphylococcus xylosus e Staphylococcus carnosus), aw, pH, cor (CIE L*a*b*), oxidação lipídica (índice de peróxidos e TBARS), oxidação proteica (tiol), pigmentos heme totais, ferro não heme e metamioglobina durante o processamento (dias 0, 2, 15 e 28) e ao longo da vida de prateleira (após 1, 30 e 120 dias). Parâmetros de textura (coesividade, flexibilidade, mastigabilidade e dureza) foram avaliados nos salames após 90 dias de armazenamento e a formação de compostos voláteis no início (1º dia) e fim do armazenamento (120º dia). O US exerceu efeito positivo no crescimento das bactérias em algumas etapas do processamento e do armazenamento (p<0,05), principalmente sobre Micrococcaceae (Staphylococcus xylosus e Staphylococcus carnosus) e com 9 min de exposição. O pH, aw e parâmetros de cor não foram afetados de maneira significativa pelo US (p>0,05). A oxidação de lipídios e de proteínas foi acelerada com o US, contudo mantendo valores aceitáveis. Os pigmentos heme totais, ferro não heme e metamioglobina foram afetados pela sonicação (p<0,05) e influenciaram nas reações oxidativas. A análise discriminatória canônica no processamento e no armazenamento separou as amostras em grupos de acordo com o dia de análise e não de acordo com os tratamentos, tanto em função do efeito preponderante do tempo de processamento/armazenamento nas características do salame quanto por falta de efeito expressivo do tempo de sonicação. O US não afetou significativamente parâmetros do perfil de textura (p>0,05), contudo dureza e mastigabilidade mostraram tendência a reduzirem com a sonicação. Com relação aos compostos voláteis, não foram encontradas diferenças estatísticas entre os tratamentos (p>0,05), com exceção de etanol e hexanol (p<0,05) no início do armazenamento. O US afetou a curva de crescimento das bactérias, acelerando ou inibindo seu crescimento em alguns pontos, e apresenta potencial a ser explorado na melhora da textura e na formação de cor vermelha do salame. A falta de efeito pronunciado do US sobre algumas características foi atribuída principalmente aos parâmetros acústicos adotados, baixo tempo de exposição ao US, consistência do salame, heterogeneidade da massa e quantidade/composição da gordura, entre outros fatores. Com isso, sugere-se a realização de mais estudos que avaliem as potencialidades do uso do US como tecnologia emergente na fabricação de salame.

No / The use of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry on intact cell microorganisms, Intact Cell MALDI (ICM), has been shown by numerous workers to yield effective species level identification. Early work highlighted the significant effect that variation in culture media, incubation conditions and length of incubation had on the spectra produced. Therefore, in order to achieve reliable and reproducible species level identification and sub-typing of microorganisms from ICM fingerprints, it has been essential to develop standardised methods. For methicillin-resistant Staphylococcus aureus (MRSA), a major nosocomial pathogen, we have developed such a standardised method. In this paper we present the experimental parameters, namely, the incubation period, the number of passages required from lyophilised or stored isolates, the method of deposition of the bacterial cells, the concentration of matrix solution, the drying time of bacterial cells prior to the addition of the matrix solution, the time between preparation of the bacterial/matrix sample and analysis and the MALDI pulsed extraction setting, which were considered during the development of defined methods.