Selection of yeast strains in naturally fermented cured meat as promising starter cultures for fermented cured beef, a traditional fermented meat product of northern China.

BACKGROUND: Fermented meat products are meat products with a unique flavor, color, and texture as well as an extended shelf life under natural or artificially controlled conditions. Microorganisms or enzymes are used to ferment the raw meat so that it undergoes a series of biochemical and physical changes. Common fermentation strains are lactic acid bacteria, yeasts, staphylococci, molds, and so forth. Studies on the inhibitory effect of yeast fermentation strain on N-nitrosamines in fermented meat products have not been reported. Two excellent yeast starters were identified to solve the problem of nitrosamines in fermented meat products. RESULTS: Meyerozyma guilliermondii and Debaryomyces hansenii led to weak acid production, strong resistance to NaCl and NaNO2 , and high tolerance to low acidic conditions. The inoculated fermented beef exhibited decreased lightness, moisture content, water activity, pH, protein content, nitrite content, and N-nitrosamine content in comparison with the control group fermented bacon. M. guilliermondii had a better effect, reducing pH from 5.69 to 5.41, protein content from 254.24 to 221.92 g·kg-1 , nitrite content from 28.61 to 25.33 mg·kg-1 and N-nitrosamine by 18.97%, and giving the fermented beef the desired meat color, mouthfeel, odor, taste, and tissue quality. CONCLUSION: In this study, two strains of yeast fermenters that can degrade N-nitrosamine precursors were identified, which to some extent solves the problem of the high risk of generating nitrosamines such as N-nitrosodiethylamine (NDEA) by processing fermented meat products with nitrites as precursors. These two strains are likely to be used as starter cultures for fermented meat products. © 2023 Society of Chemical Industry.

Optimization of antioxidant and lycopene extraction from tomato pomace using Hansen solubility parameters and its application in chicken meat preservation.

Tomato pomace, composed of peels and seeds, is often discarded or used as animal feed. However, it contains valuable phytochemicals, including lycopene. Lycopene, a natural pigment, is an antioxidant known for reducing the risk of chronic diseases like cardiovascular ailments and cancer. In this study, we aimed to study the possibility of valorizing tomato pomace by quantifying phenolic compounds, evaluating the antioxidant activity of their extracts, as well as extracting and quantifying lycopene, and studying the effect of tomato peel extract on the oxidative stability of chicken patties during storage. The effectiveness of different solvent mixtures for the extraction of lycopene was evaluated using Hansen solubility parameters (HSPs). The obtained results showed that the best solvent mixture was hexane/acetone (50/50) with a Hansen theoretical distance of 7.2, indicating its favorable solvation power. It also achieved a notable extraction yield of 3.12% and the highest lycopene yield of 20.05 mg/100 g. This combination demonstrated the highest values in terms of total phenolic (24.06 mg equivalent gallic acid/100 g dry matter) and flavonoid content (30.55 mg equivalent catechin/100 g dry matter), indicating a significant presence of these compounds. However, its 1,1-diphenyl-2-picrylhydrazyl (13.51 µg/mL) and ABTS, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, (8.52 µg/mL) IC50 values were comparatively lower than the other mixes. The use of this fraction as a food additive and antioxidant showed significant competitiveness with the conventional preservative, 2,6-di-tert-butyl-4-methylphenol. Tomato extract can be considered a potential natural preservative in food preparations due to its high lycopene content. PRACTICAL APPLICATION: This research provides valuable insights into optimizing the extraction of antioxidants from tomato pomace, using HSPs. The findings have the potential to benefit the food industry by developing improved methods for preserving chicken meat through the application of these optimized antioxidant extracts. By enhancing the preservation process, this study may contribute to extending the shelf life and maintaining the quality of chicken meat, leading to reduced food waste and improved consumer satisfaction.

Social and environmental conditions related to Mycobacterium leprae infection in children and adolescents from three leprosy endemic regions of Colombia.

BACKGROUND: Leprosy is is still considered a public health issue and in Colombia 7-10% of new cases are found in children, indicating both active transmission and social inequality. We hypothesized that circulating antibodies against Natural Octyl Disaccharide-Leprosy IDRI Diagnostic (NDO-LID) (a combination of Mycobacterium leprae antigens) could reveal the social and environmental aspects associated with higher frequencies of M. leprae infection among children and adolescents in Colombia. METHODS: An observational cross-sectional study was conducted involving sampling from 82 children and adolescents (younger than 18 years of age) who had household contact with index leprosy patients diagnosed in the last 5 years. Data were analyzed through bivariate analysis made by applying a Pearson x2 test for qualitative variables, while quantitative variables, depending on their distribution, were analyzed using either a Student's t-test or Mann-Whitney U test. Multivariate analysis was performed using a multiple regression and binomial logistic approach. RESULTS: A bivariate analysis demonstrated that antibody titers against NDO-LID were significantly greater in children and adolescents with a low socioeconomic status that had: lived in vulnerable areas of the UAChR shared region; eaten armadillo meat; exposure of over 10 years to an index case and; not received BCG immunization. Moreover, a multivariate analysis showed that residing in the UAChR region has a strong association with a greater possibility of M. leprae infection. CONCLUSIONS: M. leprae transmission persists among young Colombians, and this is associated with social and environmental conditions. An intensification of efforts to identify new leprosy cases in vulnerable and forgotten populations where M. leprae transmission continues therefore appears necessary.

Microbiota of Iberian dry-cured ham as influenced by chemical composition, high pressure processing and prolonged refrigerated storage.

The effect of high pressure processing (HPP) on the microbiota of ripened Iberian ham of different water activity, salt concentration and intramuscular fat content was investigated before and after a 5-month refrigeration period. At the beginning of the refrigeration period, the only significant effects of chemical composition were those of water activity on psychrotrophs and Micrococcaceae in untreated hams, and of the salt-in-lean ratio on lactic acid bacteria in HPP-treated hams. At the end of the refrigeration period, the only significant effect was that of intramuscular fat content on moulds and yeasts in HPP-treated samples. All microbial groups were significantly affected by HPP, with reductions ranging from 1.7 to 2.0 log cycles after treatment. A significant recovery of all microbial groups took place in HPP-treated hams during the refrigeration period, with increases ranging from 0.5 to 1.1 log cycles. In spite of this recovery, microbial levels in HPP-treated hams remained significantly lower than in untreated hams. Staphylococcus accounted for 93.4% of Iberian ham bacterial isolates, with S. equorum as the most abundant species. Representatives of the Tetragenococcus, Carnobacterium and Streptomyces genera, not previously reported in dry-cured ham, were also isolated. Most of the yeast isolates (75.0%) were identified as Debaryomyces hansenii.

Evidence of zoonotic leprosy in Pará, Brazilian Amazon, and risks associated with human contact or consumption of armadillos.

Mycobacterium leprae (M. leprae) is a human pathogen and the causative agent for leprosy, a chronic disease characterized by lesions of the skin and peripheral nerve damage. Zoonotic transmission of M. leprae to humans by nine-banded armadillos (Dasypus novemcinctus) has been shown to occur in the southern United States, mainly in Texas, Louisiana, and Florida. Nine-banded armadillos are also common in South America, and residents living in some areas in Brazil hunt and kill armadillos as a dietary source of protein. This study examines the extent of M. leprae infection in wild armadillos and whether these New World mammals may be a natural reservoir for leprosy transmission in Brazil, similar to the situation in the southern states of the U.S. The presence of the M. leprae-specific repetitive sequence RLEP was detected by PCR amplification in purified DNA extracted from armadillo spleen and liver tissue samples. A positive RLEP signal was confirmed in 62% of the armadillos (10/16), indicating high rates of infection with M. leprae. Immunohistochemistry of sections of infected armadillo spleens revealed mycobacterial DNA and cell wall constituents in situ detected by SYBR Gold and auramine/rhodamine staining techniques, respectively. The M. leprae-specific antigen, phenolic glycolipid I (PGL-I) was detected in spleen sections using a rabbit polyclonal antibody specific for PGL-I. Anti-PGL-I titers were assessed by ELISA in sera from 146 inhabitants of Belterra, a hyperendemic city located in western Pará state in Brazil. A positive anti-PGL-I titer is a known biomarker for M. leprae infection in both humans and armadillos. Individuals who consumed armadillo meat most frequently (more than once per month) showed a significantly higher anti-PGL-I titer than those who did not eat or ate less frequently than once per month. Armadillos infected with M. leprae represent a potential environmental reservoir. Consequently, people who hunt, kill, or process or eat armadillo meat are at a higher risk for infection with M. leprae from these animals.

Diversity and Characteristics of the Meat Microbiological Community on Dry Aged Beef.

Beef was dry aged for 40-60 days under controlled environmental conditions in a refrigerated room with a relative humidity of 75%-80% and air-flow. To date, there is little information on the microbial diversity and characteristics of dry aged beef. In this study, we explored the effect of change in meat microorganisms on dry aged beef. Initially, the total bacteria and LAB were significantly increased for 50 days during all dry aging periods. There was an absence of representative foodborne pathogens as well as coliforms. Interestingly, fungi including yeast and mold that possess specific features were observed during the dry aging period. The 5.8S rRNA sequencing results showed that potentially harmful yeasts/molds (Candida sp., Cladosporium sp., Rhodotorula sp.) were present at the initial point of dry aging and they disappeared with increasing dry aging time. Interestingly, Penicillium camemberti and Debaryomyces hansenii used for cheese manufacturing were observed with an increase in the dry aging period. Taken together, our results showed that the change in microorganisms exerts an influence on the quality and safety of dry aged beef, and our study identified that fungi may play an important role in the palatability and flavor development of dry aged beef.

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.

Influence of soiling on boar taint in boars.

It has been suggested that skatole, one of the main compounds responsible for boar taint, can be lowered by keeping pigs clean, as skatole can be absorbed through skin and/or lungs (Hansen, Larsen, Jensen, HansenMoller & Bartongade, 1994). With this experiment, we further investigated this hypothesis by comparing extremely clean with extremely dirty animals with regard to the occurrence of boar taint. One group of boars was washed daily and pens were mucked on and littered down daily (CLEAN), a second group of boars was rubbed with faeces daily (DIRTY) and a third group of boars was kept in control conditions (CONTROL). The treatment was performed during the last four weeks before slaughter. According to the standardised consumer panel evaluations, boars subjected to extra soiling had a higher concentration of boar taint than boars that were kept extra clean. In contrast, expert panels judged general meat flavour to be inferior in CLEAN than CONTROL pigs. The home consumer panel, the hot iron method, and laboratory analyses, i.e., the presence of indole, skatole and androstenone in fat and serum, all showed no significant differences. So no clear indications towards skatole reduction by improving cleanliness of pigs were found.

Armadillo meat intake was not associated with leprosy in a case control study, Curitiba (Brazil).

Leprosy's progression and its maintained endemic status, despite the availability of effective treatments, are not fully understood and recent studies have highlighted the possibility of involved Mycobacterium leprae ambient reservoirs. Wild armadillos can carry leprosy and, because their meat is eaten by humans, development of the disease among armadillo meat consumers has been investigated. This study evaluated the frequency of armadillo meat intake among leprosy patients as well as age and gender matched controls with other skin diseases from a dermatological unit. Armadillo meat consumption among both groups was adjusted by demographic and socioeconomic covariates based on a conditional multiple logistic regression model. One hundred twenty-one cases and 242 controls were evaluated; they differed in socioeconomic variables such as family income, hometown population and access to treated water. The multivariate analysis did not show an association between the intake of armadillo meat and leprosy (odds ratio = 1.07; CI 95% 0.56-2.04), even when only cases with no known contacts were analyzed. We conclude that leprosy is not associated with the intake of armadillo meat in these patients.

Armadillo meat intake was not associated with leprosy in a case control study, Curitiba (Brazil)

Leprosy's progression and its maintained endemic status, despite the availability of effective treatments, are not fully understood and recent studies have highlighted the possibility of involved Mycobacterium leprae ambient reservoirs. Wild armadillos can carry leprosy and, because their meat is eaten by humans, development of the disease among armadillo meat consumers has been investigated. This study evaluated the frequency of armadillo meat intake among leprosy patients as well as age and gender matched controls with other skin diseases from a dermatological unit. Armadillo meat consumption among both groups was adjusted by demographic and socioeconomic covariates based on a conditional multiple logistic regression model. One hundred twenty-one cases and 242 controls were evaluated; they differed in socioeconomic variables such as family income, hometown population and access to treated water. The multivariate analysis did not show an association between the intake of armadillo meat and leprosy (odds ratio = 1.07; CI 95 percent 0.56-2.04), even when only cases with no known contacts were analyzed. We conclude that leprosy is not associated with the intake of armadillo meat in these patients.

Efficiency of mitochondrial DNA restriction analysis and RAPD-PCR to characterize yeasts growing on dry-cured Iberian ham at the different geographic areas of ripening.

The efficiency of mitochondrial DNA (mtDNA) restriction analysis and random amplification of polymorphic DNA (RAPD)-PCR to characterize yeasts growing on dry-cured Iberian ham was evaluated. Besides, the distribution of the main species and biotypes of yeasts in the different ripening areas of this product was investigated. MtDNA restriction analysis allowed yeast characterization at species and strain level. RAPD-PCR with the primers (GACA)(4) and (GAC)(5) was inappropriate for characterization at species level. Most of the mtDNA restriction patterns detected in dry-cured Iberian ham were consistent with Debaryomyces hansenii. Several yeasts biotypes were associated to specific geographic areas of dry-cured Iberian ham ripening.

Process-oriented dose assessment model for 14C due to releases during normal operation of a nuclear power plant.

Swedish nuclear utility companies are required to assess doses due to releases of radionuclides during normal operation. In 2001, calculation methods used earlier were updated due to new authority regulations. The isotope (14)C is of special interest in dose assessments due to the role of carbon in the metabolism of all life forms. Earlier, factors expressing the ratio between concentration of (14)C in air and in various plants were used. In order to extend the possibility to take local conditions into account, a process-oriented assessment model for uptake of carbon and doses from releases of (14)C to air was developed (POM(14)C). The model uses part of DAISY which has been developed to model the turnover of carbon in crops. [Hansen, S., Jensen, H.E., Nielsen, N.E., Svendsen, H., 1993. Description of the Soil Plant System Model DAISY, Basic Principles and Modelling Approach. Simulation Model for Transformation and Transport of Energy and Matter in the Soil Plant Atmosphere System. Jordbruksförlaget, The Royal Veterinary and Agricultural University, Copenhagen, Denmark]. The main objectives were to test model performance of the former method, and to investigate if taking site specific parameters into account to a greater degree would lead to major differences in the results. Several exposure pathways were considered: direct consumption of locally grown cereals, vegetables, and root vegetables, as well as consumption of milk and meat from cows having eaten fodder cereals and green fodder from the area around the nuclear plant. The total dose of the earlier model was compared with that of POM(14)C. The result of the former was shown to be slightly higher than the latter, but POM(14)C confirmed that the earlier results were of a reasonable magnitude. When full account of local conditions was taken, e.g. as regards solar radiation, temperature, and concentration of (14)C in air at various places in the surroundings of each nuclear plant, a difference in dose between sites of approximately one order of magnitude was found.

Lipolysis of pork fat by the meat starter culture Debaryomyces hansenii at various environmental conditions.

Lipolysis of pork fat by the meat starter culture Debaryomyces hansenii added at a level of 3.5 x 10(6) cells/ml was investigated at different temperatures (10-30 degrees C), pH values (4.7-6.0). NaCl concentrations (2.5-7.5% w/v), and times of incubation (5-15 days). Pronounced growth was obtained amounting to 10(7)-10(9) cells/ml even at conditions combining the lowest temperature, the lowest pH and the highest NaCl concentration. Pork fat was hydrolysed to an extent depending on the environmental conditions. A quadratic polynomial model was developed describing the combined effects of environmental conditions on lipolysis. Regression analysis of data indicated that temperature, pH and time of incubation at conditions of meat fermentation were all significant factors in controlling lipolysis whereas NaCl concentration at the levels studied had no significant effect. Lipolysis increased when temperature increased. At 10 degrees C, lipolysis was very restricted even though growth was observed. An increase in pH resulted in higher lipolysis, the effect being most pronounced at high temperatures.

The combined effects of environmental conditions on lipolysis of pork fat by lipases of the meat starter culture organisms Staphylococcus xylosus and Debaryomyces hansenii.

The effects of environmental conditions on lipolysis by cell-free extracts from the meat starter culture organisms Staphylococcus xylosus and Debaryomyces hansenii were studied using pork fat emulsions as model systems. For the individual effects of temperature and pH it was found that the optimal conditions for the lipolysis by S. xylosus lipase were 37 degrees C and pH 7.0, and 37 degrees C and pH 6.5 for the lipolysis by D. hansenii lipase. For the combined effects of conditions relevant to meat fermentation, i.e. 10-30 degrees C, pH 4.7-6.0, 2.5-7.5% (w/v) NaCl and incubation times of 2-6 days, the empirical models indicated that temperature, pH and incubation time had important effects on total lipolysis whereas NaCl concentration had little effect. For both cultures lipolysis was strongly inhibited at conditions of meat fermentation compared to optimal conditions. For any set of the conditions which were examined the total lipolysis caused by D. hansenii lipase was lower than that caused by S. xylosus lipase.

[Non-religious prohibitions of meat consumption in Senegal]. / Interdits non religieux de la consommation de viandes au Sénégal.

680 persons belonging to all ethnical and religious groups in various regions of Senegal, have been questioned to know types of meat they avoid for non religious beliefs. The results show that: 25% of responses are related to prohibited meat for patronymic names (family names), reason comparable to "totemism". Camel flesh is in this group. 75% of responses deal with prohibitions of consumption connected with various beliefs. So is the case of goat meat avoided by 13% of persons, because it would transmit leprosy or reveal incubating diseases. 14% of persons questioned said that Spiegel lobule of liver must be exclusively consumed by only sons or only daughters. Meat taboos connected with socio-cultural beliefs (totemism, mimetism) have a minor impact on the global consumption of this food.

Effect of diet on growth of M. leprae in mouse footpads.

Semipurified diets, with equal amounts of vitamins, minerals and fibre, but varied in protein and fat content from pork, barbel fish or soya beans were tested for their possible effect on the growth of M. leprae in mouse footpads. 105 BALB/c male weanling mice were randomly divided into five diet groups of 21 mice each and fed for six months. Differences between bacterial counts of diet groups were found. The mouse foot pad model is suitable for dietary study in leprosy.