Inhibitory effects of wood extracts on the spoilage flora of marinated poultry meat

Polyphenolic compounds occurring naturally in knotwood of plants are known to have antimicrobial effects. The knots (i.e. the branch bases inside tree stems) and outer branches in pine trees contain a remarkably high concentration of phenolic stilbenes, while lignans are the major phenolic constituents of spruce knots. Large amount of these phenolic compounds can be extracted from wood knots at pulp and paper mills where their presence is undesirable. In Finland, marinating of broiler meat is done not only to increase or add value to the meat, but also to enhance the safety and shelf-life. These products are usually packed under a modified atmosphere for further protection against spoilage microorganisms. However, studies have revealed that addition of marinades to poultry products do not have an inhibitory effect on either some psychrotrophic anaerobic bacteria, such as Brochothrix thermosphacta or lactic acid bacteria associated with spoilage. Also, the activity of pathogenic Campylobacter jejuni is not affected by marinating. The objective of this study was to investigate the inhibitory and lethal activities of extracts from spruce (Picea spp.) and pine (Pinus spp.) knotwood and outer branches that are dissolved in ethanol against the spoilage microorganisms in modified atmosphere packaged marinated broiler products. Modified atmosphere packaged broiler products were separately inoculated with ‘normal’ marinades, marinades with 70% ethanol, marinades with a mixture of spruce and pine extracts dissolved in 70% ethanol or mixture of spruce and pine extracts in powder form. The bacterial colony forming units per gram obtained from each of the samples were analysed on de Man Rogosa and Sharpe agar at days 1, 6, 12 and 15. The results showed that there were significant differences in bacterial colony forming units per gram (P <0.05) between packages with ‘normal’ marinades and packages with extracts added to their marinades on the 12th and 15th day. It can be concluded that the addition of extracts from spruce and pine knotwood to marinades significantly retarded growth of spoilage microorganisms during the 15 day test period. However further research is warranted to characterise and establish the safety and suitability of the compound(s) in spruce and pine knotwood extracts that are responsible for inhibitory or lethal activity against the microbes that may be present in marinated poultry meat.

Studies on the growth temperature ranges of bacteria isolated from fresh sardine at different primary incubation temperature

The effect of primary incubation temperature on the growth temperature range was studied with reference to 296 bacterial cultures isolated from sardine using streak plate technique. The primary incubation temperature used during bacteriological sampling caused a selection of strains according to their growth temperature requirements. Incubation at 8°C caused greater recoveries of psychrotrophs while 30°C favored mesophiles. An incubation temperature of 30°C facilitated the growth of both psychrotrophs and mesophiles.

Efeito do tipo de descasque e da temperatura de armazenamento na qualidade de laranjas 'Pera' minimamente processadas

O objetivo deste trabalho foi avaliar a influência do tipo de descasque, manual, mecânico e enzimático, e do armazenamento, a 5ºC e 10ºC e ambiente (21-23ºC), na vida útil de laranjas 'Pêra' do tipo Rio, minimamente processadas. As laranjas foram colhidas maduras, e imediatamente lavadas, higienizadas e descascadas. Após a eliminação da casca, as frutas foram desinfetadas e embaladas em bandejas de isopor revestidas com filme PVC esticável. Durante o armazenamento sob as diferentes temperaturas, avaliaram-se a aparência, a quantidade de suco drenado, o aparecimento de podridões, a perda de massa fresca, a intensidade respiratória, os conteúdos de O2 e CO2 no interior das embalagens, a coloração, os teores de ácido ascórbico (AA) e de sólidos solúveis totais (SST), e acidez titulável (AT), assim como a relação SST/AT. Foram realizadas avaliações microbiológicas, bem como testes de aceitabilidade e de preferência de compra pelo consumidor. Somente os produtos descascados enzimaticamente (DE) apresentaram perda de suco, que aumentou com o tempo e a temperatura de armazenamento. A perda de massa fresca ocorreu em todos os produtos, mas os DE e os armazenados a 21-23ºC apresentaram os maiores valores. Todas as laranjas processadas apresentaram pico respiratório na primeira hora após o descascamento, seguido de redução e estabilização. O descascamento enzimático e as menores temperaturas de armazenamento levaram aos teores mais elevados de O2 e aos mais baixos de CO2, nas embalagens. As frutas processadas apresentarem baixa contagem de microrganismos mesófilos, psicrófilos e coliformes totais, e ausência de coliformes fecais. Podridões apareceram nas descascadas manual (DM) e mecanicamente (DME) após 13 dias, 8 dias e 4 dias a 5ºC e 10ºC e ambiente (21-23ºC), respectivamente. Os produtos obtidos com descascamento manual (DM) não diferiram dos DME ou DE, quanto aos teores de AT, SST e AA e relação SST/AT. Os produtos DM e DME, armazenados a 5ºC, foram os preferidos pelos provadores e apresentaram boa aparência por 19 dias e bom sabor por 23 dias. Os DE e armazenados a 5ºC apresentaram boa aparência por 4 dias e sabor desagradável no 1º dia.

Microbiological counting in lamb carcasses from an abattoir in São Paulo, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of Psychrotrophic Growth on the Milk Fat Fraction at Different Temperatures of Storage

The use of cooling, without using adequate hygienic practices in primary milk production, allows for the growth of psychrotrophic microorganisms that produce the thermoresistant lipases that give milk a rancid flavor. This study aimed to verify how the variation in temperature influences the lipolytic metabolism of the psychrotrophic organisms. Samples of raw milk were collected and submitted to laboratorial analysis as follows: psychrotrophic bacteria count, lipolytic bacteria count, and free fatty acids dosage. Each sample was divided into 3 aliquots and then incubated at 4, 8, and 12 °C, respectively. For each temperature, analyses were repeated after 12, 24, and 48 h of storage. Despite the psychrotrophs growth increase, according to temperature rise, the lipolytic metabolism was not consistent and presented the lower index at 8 °C, suggesting an intensification of the proteolytic compensatory activity at this temperature. © 2013 Institute of Food Technologists®.

Atividade proteolìtica de bactérias psicrotróficas em leites estocados em diferentes temperaturas

The widespread use of cooling technology as a tool for maintaining the microbiological and organoleptic characteristics of milk, Without effective hygienic practices throughout the milk production, caused the psychrotrophic micro-organisms to become major deteriorative bacteria in the dairy industry. The present study aimed to assess how the proteolytic psychrotrophic metabolism responds to different milk storage temperatures, drawing a parallel among psychrotrophic growth, amount of micro-organisms capable of breaking down proteins and amount of GMP (glycomacropeptide) released. Milk samples were collected directly from the cooling tank and subjected to count of psychrotrophs, count of proteolytic micro-organisms and the concentration of GMP at different storage times and temperatures. There was no linearity between the microbiological parameters and the GMP measured, according to the time/temperature binomial. The highest concentration of GMP (5.07 mg/mL) was measured in the binomial 8°C/24h (T8/ M24). The data make clear the need for further studies about questions involving the psychrotrophic microbiota in order to clarify extremely important basic questions about their metabolism.

Análise microbiológica e físico-química de material proteico comestível derivado do processamento da gordura oriunda do abate de bovinos

Background: The use of all by-products of bovine slaughter is of high economic importance for the industries of products of animal origin. Among these products, fat has an important role, once fat rendering may generate several different products, such as protein material that may be used in the manufacture of meat products. However, in spite of the importance that the use of all by-products has for the economic balance of the industry, there are no reports on their use in Brazil, or studies that supply data on microbiological and physical-chemical local standards for this protein. Thus, the objective of this study was to evaluate microbiological and physical-chemical characteristics of protein material obtained from fat rendering, as well as to provide support for companies to use fat rendering to generate protein material, adding value to industrialized meat products.Materials, Methods & Results: The experimental production of edible protein obtained of fat rendering was conducted in slaughterhouse with supervision of the Brazilian Ministry of Agriculture, Livestock and Food Supply. Protein material was obtained in a continuous, humid heat system at high temperatures. Fat scraps containing protein were ground and cooked at high temperature (85 degrees C), and placed in a three phase decanter centrifuge. After centrifugation, protein material was ground again and packed. Samples were collected from 15 batches of protein material, and the following microbiological analyses were carried out: counts of aerobic mesophilic and psychrotrophic microorganisms, coliforms at 35 degrees C, Escherichia coli, sulfite-reducing Clostridium, and Staphylococcus aureus, besides presence or absence of Salmonella and Listeria monocytogens. The following physical-chemical analyses were also carried out: protein, total lipid, moisture, ash, carbohydrate, and energy content. Mean counts of mesophiles, psychrotrophs, and coliforms at 35 degrees C were 4.17; 3.69 and 1.87 (log CFU/g), respectively. Levels of protein, total lipids, moisture, ashes and carbohydrates were 27.50; 7.83; 63.88%; 0.24%; and 0.55%, respectively, and energy content was 182.63 kcal/100g.Discussion: Results of microbiological analyses demonstrated that, although low, the final product showed to be contaminated. Contamination that occurred during the second grinding procedure may be an explanation for these bacterial counts. Also, the temperature used for fat fusion was not enough to eliminate thermoduric microorganisms. However, even with the presence of indicator microorganisms in the samples, none was contaminated by E. coli, sulfite-reducing Clostridium, S. aureus, Salmonella or L. monocytogenes. Physical-chemical analyses showed that the product had adequate nutritional quality. Based on these results, it was possible to conclude that protein material obtained in fat rendering showed characteristics that enable the use of this product as raw material for processed meat products. Besides, the present study was the first one to present scientific results in relation to edible by-products obtained in fat rendering, supplying important information for slaughterhouses and meat-processing plants. The study also produced relevant data on the innocuousness of the product, which may be used to guide decision-making of health inspectors.

Avaliação microbiológica da superfície muscular de carcaças ovinas durante as operações de abate em matadouro

In order to evaluate the hygienic-sanitary conditions of lamb carcasses for human consumption, this study aimed at quantifying populations of indicator microorganisms, such as: mesophiles and psychrotrophs, molds and yeasts, Escherichia coli, Staphylococcus spp. and at identifying pathogenic microorganisms (Salmonella sp. and Listeria spp.). The study was conducted in one lamb slaughterhouse located in the State of São Paulo. Swab samples were collected from muscle surface of forequarter and hindquarter regions of 30 half-carcasses after skinning, evisceration and washing processes. Population counts were between the following values in log10: 2,00 ± 0,32 and 2,59 ± 0,76 UFC/cm2 for mesophiles; 1,52 ± 0,98 and 2,35 ± 1,17 UFC/cm2 for psychrotrophs; 0,75 ± 0,87 and 1,23 ± 0,97 UFC/cm2 for molds and yeasts; 0,00 ± 0,00 and 0,31 ± 0,84 NMP/cm2 for Escherichia coli and 1,75 ± 0,71 and 1,95 ± 0,68 UFC/cm2 for Staphylococcus spp. Salmonella sp. and Listeria spp. were not detected from any of the sampled points. These results indicate the necessity to improve the hygienic-sanitary conditions.