Moulds contaminants on Norwegian dry-cured meat products

Alternative Additives for Organic and Natural Ready-to-Eat Meats to Control Spoilage and Maintain Shelf Life: Current Perspectives in the United States

Food additives are employed in the food industry to enhance the color, smell, and taste of foods, increase nutritional value, boost processing efficiency, and extend shelf life. Consumers are beginning to prioritize food ingredients that they perceive as supporting a healthy lifestyle, emphasizing ingredients they deem acceptable as alternative or "clean-label" ingredients. Ready-to-eat (RTE) meat products can be contaminated with pathogens and spoilage microorganisms after the cooking step, contributing to food spoilage losses and increasing the risk to consumers for foodborne illnesses. More recently, consumers have advocated for no artificial additives or preservatives, which has led to a search for antimicrobials that meet these demands but do not lessen the safety or quality of RTE meats. Lactates and diacetates are used almost universally to extend the shelf life of RTE meats by reducing spoilage organisms and preventing the outgrowth of the foodborne pathogen Listeria monocytogenes. These antimicrobials applied to RTE meats tend to be broad-spectrum in their activities, thus affecting overall microbial ecology. It is to the food processing industry's advantage to target spoilage organisms and pathogens specifically.

Regional distribution and diversity of Aspergillus and Penicillium species on Croatian traditional meat products

Various factors, such as weather and production practices (e.g., environmental hygiene, process duration, raw material quality, ripening temperature, and relative humidity), in combination with the intrinsic product properties (e.g., pH, aw, salt content), significantly affect the growth of surface moulds. The aim of this study was to isolate and identify surface moulds retrieved from traditional meat products (TMPs) and correlate these data to the production region and production technology. The surface of 250 TMPs (dry-fermented sausages, n = 108; dry-cured meat products, n = 142) from five Croatian regions were sampled during a two-year period. Dry-fermented sausages had a significantly higher pH and a lower salt concentration when compared to dry-cured meat products. In total, 528 isolates were obtained, comprising 20 Penicillium and 17 Aspergillus species. The species most frequently isolated from the dry-fermented sausages were P. commune (32.4 %), A. proliferans (33 %), and P. solitum (14.8 %), while A. proliferans (52.1 %), P. commune (28.9 %) and P. citrinum (19.7 %) predominated in dry-cured meat products. Aspergillus predominated on the TMPs from southern Croatia, while Penicillium was prevalent on products from the other four regions, possibly due to differences in weather conditions. Seven potentially mycotoxigenic species (A. creber, A. flavus, A. niger, A. westerdijkiae, P. citrinum, P. commune, and P. nordicum) were isolated and identified. Regular monitoring of mould species and their toxigenic metabolites present on traditional meat products is of the utmost importance from the public health perspective, while the results of such a monitoring can prove beneficial for the tailoring of the production technology development.

Traditional Meat Products-A Mycotoxicological Review

Traditional meat products are commonly produced in small family businesses. However, big industries are also involved in the production of this kind of product, especially since a growing number of consumers crave the traditional taste and aromas. The popularization of original and organic products has resulted in a return to traditional production methods. Traditional meat products are produced worldwide. However, in such (domesticated) conditions there is a potential danger for mycotoxin contamination. This review aims to present the sources of mycotoxins in traditional meat products, the most common mycotoxins related to such meat products, and future prospects regarding the suppression of their occurrence. Special attention should be paid to reducing the transfer of mycotoxins via the food chain from animal feed to animals to humans (stable-to-table principle), which is also described in this review. Other sources of mycotoxins (spices, environment, etc.) should also be monitored for mycotoxins in traditional production. The importance of monitoring and regulating mycotoxins in meat products, especially in traditional meat products, is slowly being recognized by the institutions and hopefully, in the future, can deliver legally regulated limits for such products. This is especially important since meat products are available to the general population and can seriously affect human health.

Spontaneously growing fungi on the surface and processing areas of matured sheep ham and volatile compounds produced

Raw ham is a dried and matured product traditionally made from pork leg, but other animals, such as sheep, can be used. The natural presence of bacteria and fungi in this product influences its characteristics throughout the process. This study analysed the fungal populations present during raw sheep hams' processing. Two types of products were developed: without and with the addition of seasonings. Mycological analyses were carried out from the ingredients, seasonings, facilities air, as well as on the surfaces of the hams and the air in the chamber throughout the maturation period (0, 45, 90, and 180 days) using 18 % dichloran glycerol agar and the data were submitted to Principal Component Analysis. Volatile compounds were evaluated at the end of the sheep ham manufacturing process through a gas chromatograph coupled to a mass spectrometer. At 45 days of aging, a more remarkable similarity was observed between the fungi present on the non-seasoned hams and those in the ripening chamber's air, while the seasoned hams showed a more evident relation with those fungi present in the spices. With time, the fungi in the air of the ripening chamber started to be influenced by Aspergillus ser. Aspergillus and Aspergillus ser. Rubri already installed in the seasoned hams at 45 days, and then it probably dispersed the non-seasoned ones due to the airborne spores, becoming the most prevalent in both treatments at 90 days. At the end of ripening, the mycobiota of both raw hams was composed mainly by xerophilic species of Aspergillus section Aspergillus. The total fungal count was 5.78 log CFU/cm2 for the non-seasoned and 7.19 log CFU/cm2 for the seasoned ones. A potentially ochratoxigenic Aspergillus ser. Circumdati was detected at the end of aging in raw, unseasoned hams. In conclusion, seasoning directly influences the species developing on the surface of seasoned hams throughout the ripening process, and indirectly affects the mycobiota of the non-seasoned hams when sharing the same ripening chamber. The presence of fungi in the matured sheep ham seems to contribute to the formation of volatile compounds, which are related to the sensory quality of these products.

Using liquid smoke to control infestations of the ham mite, Tyrophagus putrescentiae, on dry-cured hams during aging

Eight treatments of edible coatings and nets including liquid smoke (SP and 24P) and xanthan gum (XG) were used to evaluate their effectiveness at controlling mite growth on dry-cured hams. Mite growth was controlled (P < 0.05) in both coating and netting treatments of 1% SP + 1% XG. Increasing SP concentration from 1% to 2% in the SP only treatments without XG did not control mite growth (P > 0.05) in the coating but controlled mite growth (P < 0.05) when infused in the nets. Both coating and netting treatments with 2% 24P + 1% XG controlled mite growth (P < 0.05), and ham cubes with 1% and 2% 24P in infused nets had mite numbers of 4.6 and 9.4, respectively. SP did not impact the sensory attributes of the ham. Results indicate that liquid smoke can potentially be added in coatings or ham nets to control mites and used in an integrated pest management program for dry-cured hams.

Bacterial species diversity of traditionally ripened sheep legs from the Faroe Islands (skerpikjøt)

Skerpikjøt is a traditionally ripened sheep leg product from the Faroe Islands, constituting a relatively underexplored microbial ecosystem. The objective of this study is to achieve a deeper understanding of the microbial composition of this artisanal product. Nine ripened hind legs, obtained from three different producers, were assessed regarding their bacterial communities and contents of biogenic amines, including both surface and core samples. Biogenic amine concentrations were generally low, although one sample had a somewhat elevated concentration of cadaverine. Bacterial diversity was investigated by culture-dependent and culture-independent techniques. Gram-positive catalase-positive cocci (GCC) constituted the most abundant group. Within this group, Staphylococcus equorum was the most prevailing species, followed by Kocuria sp., Mammaliicoccus vitulinus, and Staphylococcus saprophyticus. Lactic acid bacteria prevailed in only one sample and were mainly represented by Latilactobacillus curvatus. Enterobacterial communities were characterised by the prevalence of Serratia proteamaculans. Despite the majority of GCC, Clostridium putrefaciens was the most abundant bacterial species in some core samples. Taken together, the culture-dependent and culture-independent identification methods gave complementary results.

Presence of aflatoxins and ochratoxin A in samarella (tsamarella), a traditional dried-cured meat of Cyprus

Dietary exposure to mycotoxins is a matter of great concern in terms of public health and regulatory bodies worldwide. Contamination of meat products with mycotoxigenic fungi and production of aflatoxins (AFs), ochratoxin A (OTA) and other mycotoxins can occur at different points of the manufacturing steps, from farm to fork. Among all microorganisms, moulds (mycobiota) are groups of microorganisms that can contaminate dry-cured meats, so they may carry the risk of mycotoxicosis. Samarella (tsamarella in Greek) is one of Cyprus's traditional, sun-dried and salted meat products. Mycological studies on this product have not been reported, and the risk of AFs or OTA has not been studied. This point of view aimed to conduct a survey study in terms of mycotoxin risk in samarella. With this aim, samples (n = 30) were collected from all commercial brands from markets in Northern Cyprus and analysed by ELISA. According to the results of this study, 14 of 30 and 9 of 30 samples were above Quantitative Measurement Limits (LOQ) for Total AFs, and AFB1, respectively. On the other hand, no result was obtained above LOQ for OTA. It was obtained that among all detectable results for total AFs, even the min result (5.3 μg/kg) was above 4 μg/kg, defined as a critical limit for directly consumed foods. None of the AFB1 and OTA results was above the determined critical limit.

Polylactic acid/polyvinyl alcohol-quaternary ammonium chitosan double-layer films doped with novel antimicrobial agent CuO@ZIF-8 NPs for fruit preservation

ZIF-8, a subclass of metal organic frameworks (MOFs), was employed as the CuO carriers because of its high surface areas and good dispersibility. A novel antibacterial agent CuO@ZIF-8 was synthesized by environmentally-friendly direct calcination strategy, and introduced into the composite double-layer films for packing materials. The double-layer films were prepared via solution casting method with polylactic acid (PLA) and polyvinyl alcohol (PVA)-quaternary ammonium chitosan as the matrix of outer layer and inner layer, respectively; and CuO@ZIF-8 nanoparticles were introduced into the PVA-quaternary ammonium chitosan layer. The double-layer films exhibited superior antibacterial activity resulted from the uniform dispersion of CuO by ZIF-8 carriers. The elongation at break was enhanced and up to 17.13%, about 2.4-fold that of PLA films. Meanwhile, the films provided low water vapor permeability and strong UV-barrier ability which were attributed to the lay-by-layer casting, CuO@ZIF-8 doping and TiO₂ addition. Cherry tomato preservation experiment revealed that the composite films retarded the growth of harmful microorganisms on the fruit surface. MTT assay confirmed the cytocompatibility of the films. The easily fabricated double-layer films presented potential possibility in the field of biodegradable food packaging.

The Influence of Surface Mycobiota on Sensory Properties of “Istarski pršut” and “Dalmatinski pršut”

This study aimed to identify surface mould species overgrowing the Croatian protected meat products “Istarski pršut” and “Dalmatinski pršut” and their effect on sensory properties. Dry-cured hams were produced in 2018/2019 and obtained from annual fairs. The predominant surface species found on “Dalmatinski pršut” were Aspergillus chevalieri, Penicillium citrinum and Aspergillus cibarius, whereas those overgrowing “Istarski pršut” were Aspergillus proliferans, P. citrinum and Penicillium salamii. The results show species diversity, higher presence, and greater variety of Aspergillus species in “Dalmatinski pršut” in comparison to “Istarski pršut”, and significant variations in 9 of 20 sensory attributes. Principal component analysis revealed a clear distinction between the two, and a large contribution of P. salamii and Penicillium bialowienzense to one principal component. The texture traits, smoky odour, muscle and subcutaneous fatty tissue colour, and mould species found are valuable for product characterisation. The results also indicate that mould species may be responsible for some sensory traits, such as tenderness, juiciness, and lesser freshness.

Pathways of Mycotoxin Occurrence in Meat Products: A Review

Documented cases of mycotoxin occurrence in meat products call for further research into potential contamination sources, especially given an ever more increasing consumption of these nutritionally rich products. These foodstuffs can be contaminated with mycotoxins through three pathways: contaminated spices and other raw materials, mycotoxin-producing moulds present on the surface of dry-cured meat products, and carry-over effect from farm animals exposed to contaminated feed. In order to establish meat products’ mycotoxin contamination more precisely, the concentrations of all mycotoxins of relevance for these products should be determined. This manuscript reviews data on major mycotoxins present in different types of meat products, and discusses the contamination pathways, contamination levels and control & preventative measures.

Suitability of FTIR to distinguish pure cultures of problematic mould species from closely related species in the meat industry

AIMS

The aim of the study was to apply Fourier Transform Infrared spectroscopy (FTIR) as a rapid screening method for moulds in a specific food production environment (cured meat) and to evaluate whether the method was sufficiently accurate to distinguish Penicillium species that constitute a hazard for the food quality and safety (Penicillium solitum and Penicillium nordicum) from closely related species.

METHODS AND RESULTS

FTIR was applied to classify the indigenous mycobiota of two production sites for dried and cured meat products in Norway. Results showed that FTIR was suitable to analyse large amounts of data. While correct classification rates varied depending on the species, overall results indicated that FTIR was able to distinguish the undesired mould species P. solitum and P. nordicum from other species and may hence present an option for rapid screening of large numbers of samples to identify changes in mould composition on site.

CONCLUSIONS

FTIR presents a potential method for detecting changes in levels of undesired fungi in meat-processing environments.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study that applies FTIR to a specific food production environment and it increases the knowledge on both possibilities and limitations of the method in classification of fungi.

The potential correlations between the fungal communities and volatile compounds of traditional dry sausages from Northeast China

The fungal communities and volatile compounds of traditional dry sausages collected from five different regions in Northeast China, including Harbin (HRB), Daqing (DQ), Suihua (SH), Hegang (HG) and Mudanjiang (MDJ) were investigated in this study. The results revealed clear differences among the fungal community structures of the sausages. Aspergillus pseudoglaucus, Debaryomyces hansenii, and Trichosporon asahii were found to be the predominant species in the sausages from HRB, HG, and MDJ, respectively. Candida zeylanoides was the predominant species in the sausage from DQ and SH. Additionally, 88 volatile compounds were identified in all sausages, of which 31 volatile compounds were the most important flavor contributors (odor activity value > 1). Potential correlation analysis revealed that 8 fungi (D. hansenii, C. zeylanoides, T. asahii, A. pseudoglaucus, Aspergillus sydowii, Penicillium expansum, A. alternata, and Alternaria tenuissima) showed significant positive correlations with ≥3 key volatile compounds. Among these fungi, D. hansenii was regarded as a core functional fungus responsible for the formation of the volatile compounds, given its strong connection with the highest number of key volatile compounds. These results provide detailed insight into the fungal communities of traditional dry sausages and a deeper understanding of the contribution of these fungi to sausage flavor.

Fungal community succession and volatile compound dynamics in Harbin dry sausage during fermentation

This study investigated the fungal community succession and volatile compound dynamics of Harbin dry sausage during a twelve-day fermentation using high-throughput internal transcribed spacer amplicon sequencing and headspace solid-phase microextraction gas chromatography-mass spectrometry. Aspergillus pseudoglaucus was found to be the primary species in the sausages during fermentation, whereas Lasiodiplodia theobromae, Alternaria alternata, Aspergillus caesiellus, and Trichosporon asahii were also prevalent. Additionally, a total of 72 volatile compounds were identified in the dry sausages, of which 24 key compounds (odor activity value > 1) dominated flavor development, including 3 aldehydes, 1 ketone, 4 alcohols, 9 esters, 4 alkenes, and 3 other compounds. Furthermore, correlation analysis suggested that most of the core fungi were positively correlated with the key volatile compounds, particularly A. pseudoglaucus, Aspergillus gracilis, Trichosporon caseorum, Debaryomyces hansenii, and T. asahii. Our findings provide novel insights into the fungal ecology and flavor development of Harbin dry sausages.

Effect of Fermentation with Two Molds on Characteristics of Chicken Meat

In the present study, we investigated the characteristics of chicken meat fermented with Penicillium nalgiovense and Penicillium chrysogenum. Hardness and springiness gradually decreased, while gumminess gradually increased during fermentation. Fermentation with P. chrysogenum led to higher hardness and lower gumminess than fermentation with P. nalgiovense. Fermentation with two molds resulted in similar microstructure, such as granule formation and fractured myofibril. The highest percentage of secondary structure was ɑ-helix, and tyrosine residues were buried after fermentation. P. nalgiovense-fermented samples contained more bound water, lower relative content of alkanes, and higher relative content of aldehydes than P. chrysogenum-fermented samples.

Characterization of Traditional Croatian Household-Produced Dry-Fermented Sausages

Characterization of five types of traditional Croatian dry-fermented sausages produced by family farms was performed via identification of superficial mycobiota, physicochemical, sensory, instrumental color, fatty acids & fat quality indices. Detailed characterization of these sausages aimed to achieve standardization of their production and composition and to establish and/or improve their specification protocols. Traditional sausages varied significantly (p < 0.05) in all analyzed parameters except for the number of mold isolates. Sausages coming from eastern Croatia had a greater mold species diversity, with the highest number of isolated mycotoxigenic species in Slavonian domestic sausage. Sensory evaluation showed good acceptability of all sausages. According to health recommendations, Kulenova Seka showed the most representable values for most of fat quality indices. The results suggest the need for certain modifications in fat & fatty acid composition and, to a lesser extent, in salt content, however not at the expense of product safety, quality and acceptability.

A study of surface moulds and mycotoxins in Croatian traditional dry-cured meat products

Xerophilic species of Aspergillus, Penicillium and Eurotium genera from surfaces of dry-cured traditional meat products (TMPs) can cause mycotoxin contamination during uncontrolled household processing. The aim of this study was to investigate into surface moulds growing on Croatian prosciuttos and fermented sausages produced in different climate regions using different technologies (n = 160), and to relate the occurrence of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) to their presence. The results revealed the Penicillium (79%) to be the dominating contaminating mould, while Aspergillus (11%), Eurotium (7%) and Mucor (4%) species were present in a significantly lower number of isolates, with higher prevalence and greater diversity in prosciuttos than in sausages, relative of the production technology and regional climate. OTA contamination (14% of samples) was significantly more frequent than that with AFB₁ (8% of samples), with OTA concentration rising to the maximal 6.86 μg/kg, whereas AFB₁ concentrations were slightly higher than, or around, the limit of quantification of the method in use, with the maximal value of 1.92 μg/kg. The presence of AFB₁ in absence of toxicogenic moulds, observed in some samples, can be attributed to contaminated spices used in TMP production or an indirect contamination via a carry-over effect.

Diversity, Distribution, and Ecology of Fungi in the Seasonal Snow of Antarctica

We characterized the fungal community found in the winter seasonal snow of the Antarctic Peninsula. From the samples of snow, 234 fungal isolates were obtained and could be assigned to 51 taxa of 26 genera. Eleven yeast species displayed the highest densities; among them, Phenoliferia glacialis showed a broad distribution and was detected at all sites that were sampled. Fungi known to be opportunistic in humans were subjected to antifungal minimal inhibition concentration. Debaryomyces hansenii, Rhodotorula mucilaginosa, Penicillium chrysogenum, Penicillium sp. 3, and Penicillium sp. 4 displayed resistance against the antifungals benomyl and fluconazole. Among them, R. mucilaginosa isolates were able to grow at 37 °C. Our results show that the winter seasonal snow of the Antarctic Peninsula contains a diverse fungal community dominated by cosmopolitan ubiquitous fungal species previously found in tropical, temperate, and polar ecosystems. The high densities of these cosmopolitan fungi suggest that they could be present in the air that arrives at the Antarctic Peninsula by air masses from outside Antarctica. Additionally, we detected environmental fungal isolates that were resistant to agricultural and clinical antifungals and able to grow at 37 °C. Further studies will be needed to characterize the virulence potential of these fungi in humans and animals.

Mycobiota and mycotoxins in Portuguese pork, goat and sheep dry-cured hams

The objectives of the present work were to survey, for the first time, the contamination of Portuguese fresh and dry-cured meat products with ochratoxin A (OTA) and aflatoxin B₁ (AFB₁), and to determine the fungi potentially responsible for this contamination. A total of 128 samples including pork fresh legs, dry-cured legs and shoulders, as well as goat and sheep dry-cured legs were analysed. Mycological analysis of these samples yielded a total of 630 fungal isolates. Penicillium sp. was the dominant fungal genus in all products (66% of all isolates). Penicillium nordicum and Aspergillus westerdijkiae were only rarely isolated from pork ham samples. In fresh pork meat, 40% of the samples were contaminated with OTA at levels below 1 μg/kg. In pork dry-cured legs with 20 to 25 months of ripening, 43% of the samples showed detectable contamination, while 18% of the shoulder hams were contaminated. OTA was not detected in any of the goat and sheep samples. OTA contamination does not seem to be a risk in small-piece and short-ripe products like goat and sheep legs, but affects longer ripe products like pork legs and shoulders. Although aflatoxigenic fungi were identified, AFB₁ was not detected in any sample, and it should not be considered a risk in dry-cured hams.

Sensitivity of food spoilage fungi to a smoke generator sanitizer

Smoke generator sanitizers are easy to handle and can access to hard-to-reach places. They are a promising alternative for controlling food and air borne fungi, which are known to cause losses in the bakery, meat, and dairy industries. Therefore, the present study aimed to evaluate the efficiency of a smoke generator sanitizer based on orthophenylphenol against ten fungal species relevant to food spoilage. The tests were carried out according to the norms by the French protocol NF-T-72281, with adaptations specific for disinfectants diffused in the air. The tests were performed in an enclosed room of approximately 32 m³. Aspergillus brasiliensis (ATCC 16404), Candida albicans (ATCC 10231), Aspergillus flavus (ATCC 9643), Aspergillus chevalieri (IMI 211382), Cladosporium cladosporioides (IMI 158517), Lichtheima corymbifera (CCT 4485), Mucor hiemalis (CCT 4561), Penicillium commune (CCT 7683), Penicillium polonicum (NGT 33/12), and Penicillium roqueforti (IMI 217568) were exposed to the smoke generator sanitizer for 7 h. The product was efficient against C. albicans and C. cladosporioides, although it was unable to reduce 4 log of the other tested species. The variable sensitivity of the fungal species to the sanitizer emphasizes the importance of confronting a target microorganism (causing problems in a specific food industry) with the sanitizer aiming to control it and obtain satisfactory results in hygiene programs.

Behavior and effect of combined starter cultures on microbiological and physicochemical characteristics of dry-cured ham

The behaviour of two combined starter cultures and their influence on the microbiological and physicochemical characteristics of dry-cured ham have been evaluated. Three lots of dry-cured hams were tested during processing (0, 9, 48, 74, 112, 142, 166 and 211 days). Lot 1 had no added starter culture. Lot 2 contained a starter culture of Penicillium chrysogenum, Penicillium digitatum, Penicillium nalgiovense, Debaryomyces hansenii, Lactobacillus plantarum, Lactobacillus acidophilus, Pediococcus pentosaceus and Micrococcus varians was and lot 3 had L. plantarum, L. acidophilus, P. pentosaceus and M. varians. The use of a selected starter culture based on a combination of lactic acid bacteria (LAB) and fungal strains with a demonstrated proteolytic activity such as P. chrysogenum and D. hansenii (lot 2) did not affect the main characteristics of dry-cured ham processing, even enhancing some desirable aspects, like its non-protein nitrogen contents. LAB strains were not significantly affected by combining them with fungal starter, and better counts were found with respect to control. A higher thiobarbituric acid reactive substances content was described in lot inoculated only with LAB (lot 3). Potentially pathogenic microorganisms were not detected in any of the lots studied. The starter culture used in lot 2 showed a potential interest for use in dry-cured ham production.

Effects of chitosan as a surface fungus inhibitor on microbiological, physicochemical, oxidative and sensory characteristics of dry fermented sausages

The study aimed to improve the quality characteristics of Turkish dry-fermented sausages (sucuk) using different concentrations of chitosan (CH) coating as superficial mold inhibitor. The sausages were treated (w/w) with chitosan (0.2%, CH1; 0.5%, CH2 and 1%, CH3), potassium sorbate (20%, PS), acetic acid (1%, AA) and distilled water. Treatment with PS and CH3 resulted in a remarkable reduction of mold and yeast counts in the sausages and on casings at the end of ripening. Total aerobic mesophilic bacteria and lactic acid bacteria (LAB) varied from 7.19-7.29 to 9.01-9.27 and from 6.37-6.44 to 8.53-8.93 log CFU/g at day 0 and 12, respectively. Treatment with chitosan did not affect the natural microbiota of the sausages. Enterobacteriaceae counts were lowered from 5.79-5.89 to 2.08-2.53 log CFU/g by chitosan. Moreover, the rate of lipid oxidation in the sausages decreased by chitosan treatment. Sensory attributes were also notably enhanced in the cooked sausages treated with chitosan.

Effect of Oregano Essential Oil and Aqueous Oregano Infusion Application on Microbiological Properties of Samarella (Tsamarella), a Traditional Meat Product of Cyprus

Different types of dried meat products manufactured by different drying and curing methods are very common and well-known with a long history all over the world. Samarella (tsamarella) is one of these products and is famous among traditionally produced meat products in Cypriot gastronomy. The aim of this study was to investigate the effect of oregano essential oil (OEO) and aqueous oregano infusion (AOI) applications on the microbiological properties of samarella. In order to carry out this study, traditional methods were followed for experimental production of samarella. As a result of this study, five percent OEO application was found to be more effective to reduce microbiological counts but this ratio of OEO application was not accepted by panelists. According to all microbiological results correlated with the sensorial scores, it is concluded that one percent OEO application can be used for samarella production as an alternative preservative method.

Isolation and molecular characterization of mycotoxigenic fungi in agarwood

Agarwood (Oudh), is often used by people in the Kingdom of Saudi Arabia. The Oudh has been mentioned in the Hadith and is traditionally used for its aroma (perfuming smell) and potential medicinal applications. The aim of the study was to isolate mycotoxigenic fungi that grow on agarwood and the factors and storage conditions that enhance their growth potential. In addition to the detection of associated mycotoxins like: Aflatoxin B1 (AFB₁) and ochratoxin A (OTA) from agarwood. Agarwood samples were collected from local markets of Jeddah governorate, Kingdom of Saudi Arabia. Standard dilution plate method was used for the isolation of fungi. Isolated fungi were identified based on morphological characteristics and confirmed using molecular biology techniques. AFB₁ and OTA were detected by High Performance Liquid Chromatography (HLPC). The results indicated that the most commonly isolated fungal genera were in the following descending order: Aspergillus, Penicillium, Fusarium and Rhizopus. Among Aspergillus genera, A. flavus and A. ochraceus were detected based on their morphology and confirmed by PCR using specific primers. It was also noted that AFB₁ was released by 15.3 and 55.0% of A. flavus and A. parasiticus isolates respectively with levels reaching up to 14.60 µg/L. The moisture content in the samples ranged from 3% to 10% affected fungal growth. AFB₁ was detected in 22 out of 50 of the samples. The maximum level of AFB₁ (50.7 µg/kg) was detected in samples with higher moisture content (12%) stored at a temperature of 32 °C. Aspergillus fungi were found to be the most predominant fungal genera found on agarwood. Moisture content (9–10%) and storage temperature (32 °C) stimulated fungal growth and their ability to produce mycotoxins. For this reason, storage conditions at the marketing place should be adequate in order not to provide a conducive environment for fungal growth which is associated with the mycotoxin production. In order to prevent fungal growth and mycotoxin production, it would be recommended to store agarwood at temperatures not exceeding 25 °C and moisture content of up to a maximum of 5–6%.

Penicillium salamii strain ITEM 15302: A new promising fungal starter for salami production

Traditional sausages are often considered of superior quality to sausages inoculated with commercial starter cultures and this is partially due to the action of the typical house microflora. Penicillium nalgiovense is the species commonly used as starter culture for dry-cured meat production. Recently a new species, Penicillium salamii, was described as typical colonizer during salami seasoning. In order to understand its contribution to the seasoning process, two different experiments on curing of fresh pork sausages were conducted using P. salamii ITEM 15302 in comparison with P. nalgiovense ITEM 15292 at small and industrial scale, and the dry-cured sausages were subjected to sensory analyses. Additionally, proteolytic and lipolytic in vitro assays were performed on both strains. P. salamii ITEM 15302 proved to be a fast growing mould on dry-cured sausage casings, well adapted to the seasoning process, with high lipolytic and proteolytic enzymatic activity that confers typical sensory characteristics to meat products. Therefore, P. salamii ITEM 15302 was shown to be a good candidate as new starter for meat industry.

Determination of lipolytic and proteolytic activities of mycoflora isolated from dry-cured teruel ham

Fungi play a key role in dry-cured ham production because of their lipolytic and proteolytic activities. In the present study, 74 fungal strains from dry-cured Teruel hams and air chambers were tested for proteolytic and lipolytic activities, with a view to their possible use as starter cultures. Lipolytic activity of fungi was studied against lauric, palmitic, stearic and oleic acids, whereas proteolytic activity was studied against casein and myosin. Of the 74 fungal strains tested, most of them demonstrated lipolytic activity (94.59 %). Lipolytic activity against lauric and oleic acids was stronger than against palmitic and stearic acids. 39 strains (52.70 %) demonstrated proteolytic activity against casein and the 6 highest proteolytic strains were also tested for pork myosin proteolysis. Some strains belonging to Penicillium commune, Penicillium chrysogenum, Penicillium nalgiovense and Cladosporium cladosporioides were selected because of their significant proteolytic and lipolytic activities and could be suitable to use as starters in dry-cured ham.

Fungal Presence in Selected Tree Nuts and Dried Fruits

Sixty-four tree nut samples (almonds, pecans, pine nuts, and walnuts) and 50 dried fruit samples (apricots, cranberries, papaya, pineapple, and raisins) were purchased from local supermarkets and analyzed for fungal contamination using conventional culture as well as molecular methods. The results of our study showed that the highest yeast and mold (YM) counts (5.34 log₁₀ CFU g⁻¹) were found in walnuts and the lowest in pecans. The most common mold in nuts was Aspergillus niger, relatively low numbers of A. flavus were found across the board, while Penicillium spp. were very common in pine nuts and walnuts. Low levels (2.00–2.84 log₁₀ CFU g⁻¹) of yeasts were recovered from only two pine nut samples. Fungal contamination in dried fruits was minimal (ranging from <2.00 to 3.86 log₁₀ CFU g⁻¹). The highest fungal levels were present in raisins. All papaya samples and the majority of cranberry, pineapple, and apricot samples were free of live fungi. The most common mold in dried fruits was A. niger followed by Penicillium spp. One apricot sample also contained low levels (2.00 log₁₀ CFU g⁻¹) of yeasts.

Fungal profiles in various milk thistle botanicals from US retail

Milk thistle (MT) dietary supplements are widely consumed due to their possible beneficial effect on liver health. As botanicals, they can be contaminated with a variety of fungi and their secondary metabolites, mycotoxins. This study was conducted in an effort to determine the mycological quality of various MT botanical supplements from the US market. Conventional plating methods were used for the isolation and enumeration of fungi, while conventional microscopy as well as molecular methods were employed for the speciation of the isolated strains. Results showed that a high percentage of the MT samples tested were contaminated with fungi. Total counts ranged between <2.00 and 5.60 log10 colony forming units per gram (cfu/g). MT whole seeds carried the highest fungal levels followed by MT cut herb. No live fungi were recovered from MT seed tea bags, liquid extracts, capsules or soft gels. Potentially toxigenic molds from the Aspergillus sections Flavi and Nigri as well as Eurotium, Penicillium, Fusarium and Alternaria species were isolated from MT supplements. The predominant molds were Eurotia (E. repens, E. amstelodami and E. rubrum), A. flavus, A. tubingensis, A. niger and A. candidus. To our knowledge, this is the first study reporting on fungal contamination profiles of MT botanicals.

Plant and fungal diversity in gut microbiota as revealed by molecular and culture investigations

BACKGROUND

Few studies describing eukaryotic communities in the human gut microbiota have been published. The objective of this study was to investigate comprehensively the repertoire of plant and fungal species in the gut microbiota of an obese patient.

METHODOLOGY/PRINCIPAL FINDINGS

A stool specimen was collected from a 27-year-old Caucasian woman with a body mass index of 48.9 who was living in Marseille, France. Plant and fungal species were identified using a PCR-based method incorporating 25 primer pairs specific for each eukaryotic phylum and universal eukaryotic primers targeting 18S rRNA, internal transcribed spacer (ITS) and a chloroplast gene. The PCR products amplified using these primers were cloned and sequenced. Three different culture media were used to isolate fungi, and these cultured fungi were further identified by ITS sequencing. A total of 37 eukaryotic species were identified, including a Diatoms (Blastocystis sp.) species, 18 plant species from the Streptophyta phylum and 18 fungal species from the Ascomycota, Basidiomycota and Chytridiocomycota phyla. Cultures yielded 16 fungal species, while PCR-sequencing identified 7 fungal species. Of these 7 species of fungi, 5 were also identified by culture. Twenty-one eukaryotic species were discovered for the first time in human gut microbiota, including 8 fungi (Aspergillus flavipes, Beauveria bassiana, Isaria farinosa, Penicillium brevicompactum, Penicillium dipodomyicola, Penicillium camemberti, Climacocystis sp. and Malassezia restricta). Many fungal species apparently originated from food, as did 11 plant species. However, four plant species (Atractylodes japonica, Fibraurea tinctoria, Angelica anomala, Mitella nuda) are used as medicinal plants.

CONCLUSIONS/SIGNIFICANCE

Investigating the eukaryotic components of gut microbiota may help us to understand their role in human health.