Study of the bacterial profile of raw milk butter, made during a challenge test with Listeria monocytogenes, depending on cream maturation temperature.

Bacteria can play different roles and impart various flavors and characteristics to food. Few studies have described bacterial microbiota of butter. In this study, next-generation sequencing was used to determine bacterial content of raw milk butter, processed during a challenge test, depending on cream maturation temperature and on the presence or not of L. monocytogenes. Two batches were produced. pH and microbiological analyses were conducted during cream maturation and butter storage. DNA was also isolated from all samples for 16S rRNA amplicon sequencing analysis. For butter made from cream matured at 14 °C, a growth potential of L. monocytogenes of - 1.72 log cfu/g was obtained. This value corresponds to the difference between the median of counts at the end of storage and the median of counts at the beginning of storage. This butter (pH value of 4.75 ± 0.04) was characterized by a dominance of Lactococcus. The abundance of Lactococcus was significantly higher in inoculated samples than in control samples (p value < 0.05). Butter made from cream matured at 4 °C (pH value of 6.81 ± 0.01) presented a growth potential of 1.81 log cfu/g. It was characterized by the abundance of psychrotrophic bacteria mainly Pseudomonas. This study demonstrated that cream maturation temperature impacts butter microbiota, affecting thus product's characteristics and its ability to support or not the growth of pathogens like L. monocytogenes.

Bacterial and oxidative control of local butter with smart/active film based on pectin/nanoclay/Carum copticum essential oils/ß-carotene.

In this study, Pectin/Nanoclay (montmorillonite)/Carum copticum Essential oils/ß-Carotene (Pec/Clay/CCE/ßC) composite film was prepared. The effect of ß-Carotene (ßC) and Carum copticum Essential oils (CCE) concentration on the antioxidant activity and color/mechanical properties of Pec/Clay/CCE/ßC film was studied. The morphology and antibacterial activity of film were studied. The films containing maximum essential oil and ß-carotene showed the best antibacterial activity, antioxidant activity, flexibility and firmness. So the Pec/Clay/CCE0.5%/BC0.03% film as the optimum film was used for packaging of local butter. Oxidative stability, microbial count, and color properties (L*, a* and b*) of butter packaged with active film (Pec/Clay/CCE/ßC) were investigated. Results showed that Pec/Clay/CCE/ßC film was effective against Bacillus cereus (B. cereus) more than Escherichia coli (E. coli). According to the results active packaged butter had the highest oxidative stability, lowest microbial load, and the least color change during storage. In the packaging process, Pec/Clay/CCE/ßC film color was changed from orange to light yellow and this color change was used as a smart color indicator to detect the oxidation of butter and expiration time of butter.

Assessment of growth and survival of Listeria monocytogenes in raw milk butter by durability tests.

Butter is a complex matrix characterized by a high fat content. Existing publications on the behavior of Listeria monocytogenes in this type of food reported contrasted results. This study was performed to provide further information and data about raw milk butter's ability to support survival or growth of L. monocytogenes. Durability tests were performed on naturally contaminated samples of raw milk butter with various physico-chemical characteristics. At the end of shelf life, no growth of L. monocytogenes was observed in the studied butters, regardless of their physico-chemical characteristics (pH, aw, water dispersion index and salt concentration) and the initial level of contamination. The number of positive samples and the colony counts of L. monocytogenes were even decreased at the end of the storage period.

Avaliação da qualidade microbiológica das manteigas a granel e manteigas de garrafa vendidas em estabelecimentos comerciais e feiras livres na cidade de União dos Palmares-Alagoas / Evaluation of the microbiological quality of bulk butters and bottle butters sold in commercial establishments and free trade fairs in the Palmares-Alagoas Union

A manteiga é um produto gorduroso obtido pela batenção do creme de leite derivado do leite da vaca, formando uma emulsão do tipo água/óleo. Durante o processo de fabricação, se não houver aplicação de boas práticas, os microrganismos têm grande oportunidade de contaminar a manteiga. Por isso, as práticas higiênico-sanitárias devem ser adotadas com intuito de prevenir eventuais contaminações ou recontaminações do creme. Em Alagoas é comum a comercialização e o consumo de manteiga artesanal, ou seja, manteigas produzidas manualmente, por pequenos produtores/ou pequenos laticínios, bem como manteigas de garrafas ou manteiga da terra que são frequentemente comercializadas diretamente por eles em feiras livres e/ou em pequenos estabelecimentos comerciais. Esta pesquisa objetivou-se avaliar a qualidade microbiológica das manteigas vendidas a granel e manteigas de garrafa vendidas no município de União dos Palmares/AL. Foram coletadas amostras de cada tipo de manteiga em três coletas diferentes em meses seguidos. As análises microbiológicas foram realizadas no Laboratório de Análises Microbiológicas do Instituto Federal de Alagoas-IFAL campus Murici/AL, usando-se a metodologia APHA e como parâmetro de qualidade usou-se o Regulamento técnico de identidade e qualidade. Observou-se com os resultados das análises, que as manteigas vendidas nas feiras e comércios de União dos Palmares/AL, encontravam-se dentro do estabelecido pela legislação vigente.

Yeasts and filamentous fungi associated with some dairy products in Egypt.

This work aimed to identify and evaluate the diversity of yeasts and filamentous fungi that contaminate some dairy products (fresh buffalo milk, plain yoghurt, butter and Kareisk cheese) in Assiut city, Egypt. The identification was based on phenotypic characteristics, and genotypically in case of yeasts. The pHs of all dairy products lie within the acidic range, but yoghurt registered the highest value. A total of 41 genera and 89 species+3 varieties were recovered from all dairy products investigated on DRBC (26 genera representing 59 species+1 variety), DG18 (32 genera, 56 species+2 varieties) and MY50G (31 genera, 64 species+2 varieties). From these, filamentous fungi were represented by 21 genera and 59 species+2 varieties, and yeasts by 20 genera and 30 species+1 variety. In all products except yoghurt, the xerophilic media (DG18 and MY50G) supported more diversity of fungal species than the general medium (DRBC). Reversely, DRBC supported more propagules originated from all products than DG18 and DRBC. On the other hand, the highest numbers of propagules were recovered from Kareish cheese and butter on MY50G, while the lowest numbers were recorded from yoghurt and raw milk on MY50G. Moreover, yeasts constituted the greatest part of propagules from the four products on the three isolation media except the raw milk on MY50G. From yeasts, Candida, Cyberlindnera, Debaryomyces, Galactomyces, Kazachstania, Kluyveromyces, Myerozyma, Pichia, Rhodotorula, Trichosporon; and from filamentous fungi, only Aspergillus, Cladosporium, Mucor and Penicillium were found contaminating all dairy products. Possible medical problems related to the presence of these fungi or to their metabolic products are discussed.

Qualidade microbiológica de manteigas extra qualidade / Microbiological quality of extra quality butters

A manteiga é um produto lácteo fabricado a partir do creme de leite pasteurizado. É necessária uma série de condições e cuidados, desde a obtenção da matéria-prima até a sua comercialização, para evitar o comprometimento da sua qualidade e evitar danos à saúde do consumidor. Nessa perspectiva, este trabalho avaliou a qualidade microbiológica de diferentes marcas de manteiga extra qualidade comercializadas no norte do Mato Grosso. Foram determinados coliformes totais, termotolerantes e Escherichia coli, bolores e leveduras. Todas as marcas avaliadas apresentaram resultados negativos para coliformes. Os resultados da contagem de bolores e leveduras variaram de 1,0x102 a 8,37x104 UFC/g.(AU)

Longer Contact Times Increase Cross-Contamination of Enterobacter aerogenes from Surfaces to Food.

Bacterial cross-contamination from surfaces to food can contribute to foodborne disease. The cross-contamination rate of Enterobacter aerogenes on household surfaces was evaluated by using scenarios that differed by surface type, food type, contact time (<1, 5, 30, and 300 s), and inoculum matrix (tryptic soy broth or peptone buffer). The surfaces used were stainless steel, tile, wood, and carpet. The food types were watermelon, bread, bread with butter, and gummy candy. Surfaces (25 cm2) were spot inoculated with 1 ml of inoculum and allowed to dry for 5 h, yielding an approximate concentration of 107 CFU/surface. Foods (with a 16-cm2 contact area) were dropped onto the surfaces from a height of 12.5 cm and left to rest as appropriate. Posttransfer, surfaces and foods were placed in sterile filter bags and homogenized or massaged, diluted, and plated on tryptic soy agar. The transfer rate was quantified as the log percent transfer from the surface to the food. Contact time, food, and surface type all had highly significant effects (P < 0.000001) on the log percent transfer of bacteria. The inoculum matrix (tryptic soy broth or peptone buffer) also had a significant effect on transfer (P = 0.013), and most interaction terms were significant. More bacteria transferred to watermelon (∼0.2 to 97%) than to any other food, while the least bacteria transferred to gummy candy (∼0.1 to 62%). Transfer of bacteria to bread (∼0.02 to 94%) was similar to transfer of bacteria to bread with butter (∼0.02 to 82%), and these transfer rates under a given set of conditions were more variable than with watermelon and gummy candy. IMPORTANCE: The popular notion of the "five-second rule" is that food dropped on the floor and left there for <5 s is "safe" because bacteria need time to transfer. The rule has been explored by a single study in the published literature and on at least two television shows. Results from two academic laboratories have been shared through press releases but remain unpublished. We explored this topic by using four different surfaces (stainless steel, ceramic tile, wood, and carpet), four different foods (watermelon, bread, bread with butter, and gummy candy), four different contact times (<1, 5, 30, and 300 s), and two bacterial preparation methods. Although we found that longer contact times result in more transfer, we also found that other factors, including the nature of the food and the surface, are of equal or greater importance. Some transfer takes place "instantaneously," at times of <1 s, disproving the five-second rule.

Influence of water activity on inactivation of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in peanut butter by microwave heating.

This study evaluated the efficacy of a 915 MHz microwave with 3 different electric power levels to inactivate three pathogens in peanut butter with different aw. Peanut butter inoculated with Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium and Listeria monocytogenes (0.3, 0.4, and 0.5 aw) were treated with a 915 MHz microwave with 2, 4, and 6 kW for up to 5 min. Six kW 915 MHz microwave treatment for 5 min reduced these three pathogens by 1.97 to >5.17 log CFU/g. Four kW 915 MHz microwave processing for 5 min reduced these pathogens by 0.41-1.98 log CFU/g. Two kW microwave heating did not inactivate pathogens in peanut butter. Weibull and Log-Linear + Shoulder models were used to describe the survival curves of three pathogens because they exhibited shouldering behavior. Td and T5d values were calculated based on the Weibull and Log-Linear + Shoulder models. Td values of the three pathogens were similar to D-values of Salmonella subjected to conventional heating at 90 °C but T5d values were much shorter than those of conventional heating at 90 °C. Generally, increased aw resulted in shorter T5d values of pathogens, but not shorter Td values. The results of this study can be used to optimize microwave heating pasteurization system of peanut butter.

Effect of cream fermentation on microbiological, physicochemical and rheological properties of L. helveticus-butter.

The primary objective of this study was to evaluate the physicochemical and rheological properties of butter produced by Lactobacillus helveticus fermented cream. The incorporation of putative probiotic - the L. helveticus, to ferment cream prior to butter production was anticipated to alter the nutritional composition of butter. Changes in crude macronutrients and the resultant modification relating to textural properties of butter induced upon metabolic activities of L. helveticus in cream were focused in this research. Fermented butter (LH-butter) was produced by churning the cream that was fermented by lactobacilli at 37 °C for 24 h. Physicochemical analysis, proximate analysis and rheology properties of LH-butter were compared with butter produced using unfermented cream (control). LH-butter showed a significantly (P<0.05) higher fat content and acid value; lower moisture and ash; and was softer than the control. Cream fermentation modified nutritional and textural properties of butter in which LH-butter contained higher health beneficial unsaturated fatty acids than the control and thus rendered the product softer. Its enrichment with probiotics could thus further enhance its functional property.

Ability of Lactobacillus plantarum MON03 to mitigate aflatoxins (B1 and M1) immunotoxicities in mice.

Aflatoxin B1 (AFB1) and M1 (AFM1) are mycotoxins produced by numerous Aspergillus species in pre- or post-harvest cereals and milk. AFB1 and AFM1 display a potent economic loss in livestock and also cause severe immunological problems. The aims of this study were to: evaluate a new AFB1 and AFM1-binding/degrading micro-organism for biological detoxification; examine its ability to degrade AFB1 and AFM1 in liquid medium; and evaluate its potential for in vivo preventative effects against AFB1- and AFM1-induced immunomodulation in mice. Lactobacillus plantarum MON03 (LP) isolated from Tunisian artisanal butter was found to display significant binding ability to AFB1 and AFM1 in PBS (i.e. 82% and 89%, respectively) within 24 h of incubation and able to tolerate gastric acidity, have strongly hydrophilic cells surface properties, and adhere efficacy to Caco-3 cells in vitro. The in vivo study was conducted using Balb/c mice that received by oral gavage vehicle (control), LP only (2 × 10(9) CFU/L, ~2 g/kg BW), AFB1 or AFM1 alone (0.25 and 0.27 mg/kg, respectively), or AFB1 + LP or AFM1 + LP daily for 15 days. Compared to in control mice, treatments with AFB1 and AFM1 led to significantly decreased body weight gains, histopathological changes, and decrements in all hematologic and immune parameters assessed. Co-treatment with LP strongly reduced the adverse effects of each mycotoxin. In fact, the mice receiving AFB1 + LP or AFM1 + LP co-treatment displayed no significant differences in the assayed parameters as compared to the control mice. By itself, the bacteria alone had no adverse effects in the mice. From these data, it is concluded that the tested bacteria could be beneficial in biotechnology detoxification of contaminated food and feed for humans and animals.

Potential preventive role of lactic acid bacteria against aflatoxin M1 immunotoxicity and genotoxicity in mice.

Aflatoxin M1 (AFM1) is a mycotoxin produced by numerous Aspergillus species in pre- or post-harvest cereals and milk. Exposure to AFM1 imparts potent economic losses in the livestock industry. Toxicologically, it also causes severe immune system problems. The aims of this study were to evaluate a new AFM1-binding/degrading microorganism for biologic detoxification, to examine its ability to degrade AFM1 in liquid medium, and to evaluate its potential for in vivo preventative effects against AFM1-induced immunotoxicity and genotoxicity in mice. Lactobacillus plantarum MON03 (LP) isolated from Tunisian artisanal butter was found to display significant binding ability to AFM1 in PBS (93%) within 24 h of incubation. Further, the LP was able to tolerate gastric acidity, bile salts, and adhere efficiently to Caco-3 cells in vitro. The in vivo study used Balb/c mice that received either vehicle (control), LP only (at 1 × 10(9)CFU/L, ∼1 mg/kg bw), AFM1 (100 mg/kg bw), or AFM1 + LP daily for 15 days (by gavage); two other groups received a single dose of colchicine (4 mg/kg) or mitomycin C (1 mg/kg) as positive controls for induction of micronuclei and chromosomal aberrations, respectively. The results showed that, compared to in control mice, AFM1 treatment led to significantly decreased body weight gains, and caused cytotoxic/genotoxic effects as indicated by increases in frequencies of polychromatic erythrocytes, as well as those with micronucleation (PCEMN) and chromosomal aberrations, among bone marrow cells. The concurrent administration of LP with AFM1 strongly reduced the adverse effects of AFM1 on each parameter. Mice receiving AFM1 + LP co-treatment displayed no significant differences in the assayed parameters as compared to the control mice. By itself, the bacteria caused no adverse effects. Based on the data, it is concluded that the test bacteria could potentially be beneficial in the detoxification of AFM1-contaminated foods and feeds for humans and animals.

[A fever of finally known origin]. / FUO - alles in Butter?

We present the case of a 77 year old man with fever of unknown origin. Despite a thorough assessment in hospital the diagnosis could only be made after discharge when positive results for C. burnetii serology revealed acute Q-fever. However, retrospectively history and clinical findings matched well with acute Q-fever.

High sensitivity chemiluminescence enzyme immunoassay for detecting staphylococcal enterotoxin A in multi-matrices.

In this study, detection of staphylococcal enterotoxin A (SEA) in multi-matrices using a highly sensitive and specific microplate chemiluminescence enzyme immunoassay (CLEIA) has been established. A pair of monoclonal antibodies (mAbs) was selected from 37 anti-SEA mAbs by pairwise analysis, and the experimental conditions of the CLEIA were optimized. This CLEIA exhibited high performance with a wide dynamic range from 6.4 pg mL(-1) to 1600 pg mL(-1), and the measured low limit of detection (LOD) was 3.2 pg mL(-1). No cross-reactivity was observed when this method was applied to test SEB, SEC1, and SED. It has also been successfully applied for analyzing SEA in a variety of environmental, biological, and clinical matrices, such as sewage, tap water, river water, roast beef, peanut butter, cured ham, 10% nonfat dry milk, milk, orange juice, human urine, and serum. Thus, the highly sensitive and SEA-specific CLEIA should make it attractive for quantifying SEA in public health and diagnosis in near future.

Conditions associated with Clostridium sporogenes growth as a surrogate for Clostridium botulinum in nonthermally processed canned butter.

The objective of this study was to better understand the effect of butter composition and emulsion structure on growth and survival of Clostridium sporogenes, used as a surrogate for C. botulinum in canned butter. The lack of a thermal process step in commercially available canned butter raises questions of potential safety, because it is hermetically sealed and generally exhibits anaerobic growth conditions, which are optimal for Clostridium botulinum growth. Without thermal processing, low-acid canned foods must have inhibitory factors present to prevent C. botulinum growth. Some potential intrinsic inhibitory factors, or hurdles, within butter include: reduced water activity, acidity in cultured products, elevated salt content, and the micro-droplet nature of the aqueous phase in the butter emulsion. It was hypothesized that a normal, intact butter emulsion would have sufficient hurdles to prevent C. botulinum growth, whereas a broken butter emulsion would result in a coalesced aqueous phase that would allow for C. botulinum growth. Batch-churned butter was inoculated with C. sporogenes; butter samples with varying salt contents (0, 0.8, 1.6, and 2.4% wt/wt NaCl) were prepared and stored in coated steel cans for varying times (1 or 2 wk) and temperatures (22 or 41°C) to determine temperature and emulsion structure effects on C. sporogenes growth. Samples stored at 41°C showed a significant increase in C. sporogenes growth compared with those stored at 22°C. Furthermore, NaCl addition was found to have a significant effect on C. sporogenes growth, with 0.8% NaCl promoting more growth than 0%, but with decreases in growth observed at 1.6 and 2.4%. Uninoculated control plates were also found to have bacterial growth; this growth was attributed to other anaerobic bacteria present within the cream. It was concluded that removal of the hurdle created by the micro-droplet size of the emulsion aqueous phase could result in C. botulinum growth even at elevated salt levels and, therefore, home preparation of canned butter is not advisable. It is also possible that commercially canned butter, if heat abused, could potentially allow for C. botulinum growth and, therefore, consumption is not recommended.

Qualidade microbiológica de manteiga de garrafa comercializada no município de Petrolina, PE / Microbiological quality of bottled butter commercialized in the city of Petrolina, PE

A manteiga de garrafa é um alimento muito apreciado nos estados do Nordeste do Brasil, onde sua produção ocorre predominantemente de forma artesanal. Nesse trabalho, objetivou-se avaliar a qualidade microbiológica da manteiga de garrafa produzida e comercializada no município de Petrolina, PE.

Survival and heat resistance of Salmonella enterica and Escherichia coli O157:H7 in peanut butter.

Significant differences (P < 0.05) were found between the survival rates of Salmonella enterica and Escherichia coli O157:H7 in peanut butter with different formulations and water activity. High carbohydrate content in peanut butter and low incubation temperature resulted in higher levels of bacterial survival during storage but lower levels of bacterial resistance to heat treatment.

Transesterification of used edible and non-edible oils to alkyl esters by Aspergillus sp. as a whole cell catalyst.

Aspergillus sp. (MTCC 5436), isolated from contaminated clarified butter was used as a whole cell catalyst for transesterification of oils from different sources. The strain was observed to be tolerant and grow in 90% oil as carbon source. Oils of Jathropa, karanj and spent cottonseed were used as carbon sources in the study. The product, alkyl ester, was characterized and quantified using (1) H-NMR. The strain was observed to facilitate transesterification in an oil:minimal medium with the ratio of 70:30 resulting in a 98% conversion of oil to ethyl esters within 48 h at 28 °C and 120 rpm. The physico-chemical characteristics of the ethyl ester (>98%) at 70% oil as carbon source were similar to the standards specified for biodiesel as per standards of American Society for Testing and Materials (ASTM) and Bureau of Indian Standards (BIS), India.

Flavor evaluation of yak butter in Tsinghai-Tibet Plateau and isolation of microorganisms contributing flavor.

Yak butter in Tsinghai-Tibet Plateau possesses the characters of high energy, abundant alimentation and a special flavor with certain medical and health care functions. In this paper the organoleptic flavor of yak butter was estimated, and 28 kinds of substance with different flavors were identified with the technique of coupling gas chromatography to mass spectroscopy (GC-MS). The results showed that there are many microorganisms in yak butter with natural inoculation, which contribute to the formation of its special flavors. It was found that three of these 15 microorganisms, identified as Saccharomycetaceae, Penicillium and Asperillus separately, contributed the most to flavors. The microorganisms are expected to be applied in the food industry, especially to produce dairy food with the unique flavor of yak butter.

Microbiological quality and safety of cooking butter in Beni-Suef governorate-Egypt.

BACKGROUND: Cooking butter is one of the most popular types of fat consumed in Egyptian houses. It is produced in villages by rural women that are usually using their traditional knowledge during manufacturing. OBJECTIVE: To study the rate of contamination and hygienic quality of cooking butter METHODS: A total of 60 random samples of cooking butter, were collected from different farmers' houses in different villages, Beni-Suef Governorate, Egypt. Cooking butter samples were examined for psychrotrophic bacteria, total coliforms, faecal coliforms and molds and yeasts counts. Additionally examination for the presence of pathogenic bacteria like E.coli, S.aureus and Ps.aeruginosa were also performed. RESULTS: The microbiological examination revealed that 100, 100, 36.7, 31.7, 31.7 and 23.3% of the examined samples were contaminated by psychrotrophic bacteria, molds and yeasts, coliforms, faecal coliforms, E.coli and S.aureus, respectively. None of the examined cooking butter samples contained Ps.aeruginosa. The means values of sodium chloride and titratable acidity were 0.57 ± 0.05 % and 0.20 ± 0.013%, respectively. CONCLUSION: The present study showed that cooking butter is produced under unhygienic condition and without good manufacturing practice. The Public health significance and suggestive control measures are discussed.

Characterization of butter spoiling yeasts and their inhibition by some spices.

This study was designed to identify the yeasts in packaged and unpackaged butters and screen antiyeast activity of spices, including marjoram (Origanum majorana L.), summer savory (Satureja hortensis L.), and black cumin (Nigella sativa L.) against the most dominant yeast species in the packaged and unpackaged butters. Mean total yeast populations were 5.40 log CFU/g in unpackaged butter samples and 2.22 log CFU/g in packaged butter samples, indicating better hygienic quality of packaged samples. Forty-nine yeast species were isolated and identified from butter samples with the most prevalent isolates belonging to genera Candida-C. kefyr, C. zeylanoides, and C. lambica-and with moderate number of isolates belonging to genera Cryptococcus, Rhodotorula, Saccharomyces, and Zygosaccharomyces. Black cumin exhibited the highest antiyeast activity against C. zeylanoides and C. lambica species, even inhibited these species, while summer savory inhibited C. kefyr. The results of this study revealed clear antimicrobial potential of black cumin against the yeast species isolated from butters. Marjoram, summer savory, and black cumin could be used as natural antimicrobial agents against spoilage yeasts in food preservation, especially in butter.