Papers by Musafiri Karama
Microbiology Research, Apr 22, 2024
Gut Pathogens, Dec 5, 2023
Journal of Clinical Microbiology, Nov 1, 2008
Journal of Food Protection, Sep 1, 2003
Staphylococcus aureus is an important cause of mastitis in cows. The ability of S. aureus strains... more Staphylococcus aureus is an important cause of mastitis in cows. The ability of S. aureus strains to produce one or more enterotoxins in milk and dairy products is linked to staphylococcal food poisoning. To determine whether staphylococcicausing bovine mastitis could cause human foodborne intoxication, the production of staphylococcal enterotoxins A through D (SEA, SEB, SEC, and SED) by 160 S. aureus isolates was evaluated with the use of a reverse passive latex agglutination enterotoxin kit. All S. aureus strains were isolated over a 9-month period from 2,343 routine submissions of a composite quarter collection of individual mastitic cows at 18 dairy farms in the San Joaquin Valley in California. Prior to enterotoxin detection, isolates were grown by a method that enhances the in vitro synthesis of enterotoxin. Twenty-two of 160 S. aureus isolates produced enterotoxin. Seven produced SEC, 12 produced SED, and 3 produced both SEC and SED. None of the isolates produced SEA or SEB.
Journal of Food Protection, Dec 1, 2004
The likelihood that milk and milk products may act as a vehicle for antibiotic-resistant bacteria... more The likelihood that milk and milk products may act as a vehicle for antibiotic-resistant bacterial genes has become a concern to the food industry and a public health issue, and the demand for rapid tests has increased. The purity of DNA extracted from food samples is a key issue in the sensitivity and usefulness of biological analyses, such as PCR for pathogens and nonpathogens. A rapid, phenol-chloroform free method based on a modification of a sodium iodide DNA extraction, followed by a two-step PCR was developed for direct detection of the tet(M) gene in milk samples within a single working day. This study compares the proposed method with a traditional phenol solvent extraction method and with a commercial kit (QIAamp DNA blood mini kit, Qiagen). The three DNA extraction methods were used to ensure access to the tet(M) gene from 1 ml of raw milk, inoculated with a strain of Enterococcus faecalis, which carries the tet(M) gene. The proposed method, followed by a two-step PCR with nested primers specific for the tet(M) gene, was able to reach a detection limit below 10 CFU/ml in less than 4 h, including the two amplification cycles, thus outperforming in sensitivity and rapidity both the traditional and the commercial method.
Italian Journal of Food Safety, Jun 21, 2022
Packaging is considered one of the most interesting technological aspects of food production and ... more Packaging is considered one of the most interesting technological aspects of food production and is a constantly evolving subject in food production. The type of packaging is important for the quality and safety of the product and for the visual appearance of the product to be immediately evaluated by consumers. The purpose of this study was to investigate the effect of four different types of modified atmosphere packaging (ATM) and vacuum packaging (VP) currently used by a company in central Italy, on the main qualitative characteristics of beef. For these two traditional and two new solutions with reduced environmental impact and compostable were evaluated. For each type of packaging, two different products were analyzed: steaks and hamburgers. The samples, immediately after production, were transported to the laboratory in refrigerated containers. Several parameters (color, pH, water holding capacity, drip loss, and microbiological characteristics) were evaluated at time 0 and after 7 (T7), 14 (T14) and 21 days (T21) of storage in the dark and at refrigeration temperature (+4°C ± 2°C). The results showed that the two types of packaging have very similar effects on the water-retaining capacity of the steaks. More noticeable differences were recorded by the colorimetric analysis: for both steaks and hamburgers, the products packaged in the traditional packaging appeared brighter and redder than those packaged in the new alternatives. The microbiological analysis of the steaks showed higher values in the "new" packaging. The formation of abundant ropy slime was observed in one of the samples in the "new" modified atmosphere package at T21. The results of this study showed that the technological characteristics (in particular, the color) and the microbiological characteristics of the steaks and hamburgers were better in "old" packaging, with a better appearance and a longer shelf life. The results obtained show how the research for eco-sustainable products for packaging must be addressed, taking into account the effect of the materials on the qualitative and hygienic-sanitary characteristics of the meat.
Journal of Dairy Science, Nov 1, 2014
Several widespread occurrences of anomalous blue coloration of Mozzarella cheese have been record... more Several widespread occurrences of anomalous blue coloration of Mozzarella cheese have been recorded in the United States and some European countries. Official laboratory analysis and health authorities have linked the occurrences to contamination of the processing water with strains of Pseudomonas fluorescens, although several experts questioned how to unequivocally link the blue color to the presence of the microorganism. To establish a method to determine whether a given Pseudomonas spp. strain is responsible for the defect and study the evolution of the coloration under different storage conditions, we developed an in vitro system for the evaluation of blue coloration of Mozzarella cheese intentionally contaminated with strains of P. fluorescens. The purpose of the system was to determine whether P.fluorescens strains, isolated from Mozzarella cheese with anomalous blue coloration, were able to reproduce the blue coloration under controlled experimental conditions. Thirty-six trials of experimental inoculation of Mozzarella cheese in different preservation liquids were conducted using various suspensions of P.fluorescens (P. fluorescens ATCC 13525, P.fluorescens CFBP 3150, and P. fluorescens 349 field strain isolated from blue-colored Mozzarella cheese) at different concentrations and incubated at different temperatures. Growth curves of all tested P.fluorescens strains demonstrated that after 3 d of incubation the concentration was generally >10 6 cfu/g of Mozzarella cheese incubated in either tryptic soy broth (control) or conditioning brine. Prolonged incubation for 5 d at either 20°C or 8°C led to concentrations up to 10 9 cfu/g of Mozzarella cheese incubated in tryptic soy broth and up to 10 8 cfu/g of Mozzarella cheese incubated in preservation liquid. All Mozzarella cheeses inoculated with the field strain of P. fluorescens, except those opened 1 h after packaging and stored at 8°C, showed the characteristic anomalous blue coloration, which appeared from 1 to 72 h after opening the packaging, and was proportional to colony count, duration of storage, and storage temperature. With the proposed system, which enabled a larger number of samples to be analyzed under controlled experimental conditions and a large amount of data to be generated in a short time, we described precisely how and under which conditions the presence of P. fluorescens in Mozzarella cheese is responsible for the anomalous blue coloration. The system will help producers intercept contaminated batches and help consumers avoid the conditions under which the defect can appear.
IntechOpen eBooks, Jun 28, 2022
Onderstepoort Journal of Veterinary Research, May 28, 2019
Campylobacter spp. are the leading cause of bacterial diarrhoeal diseases globally. Around 400-50... more Campylobacter spp. are the leading cause of bacterial diarrhoeal diseases globally. Around 400-500 million cases of Campylobacter infections occur each year globally (Friedman et al. 2000). Although most human cases of campylobacteriosis are foodborne or waterborne (Jacobs-Reitsma, Lyhs & Wagennar 2008), a number of studies have shown that contact with dogs is a risk factor for human campylobacteriosis (Couturier,
Meat Science, 2018
This study evaluated the effect of a novel formulation for starter culture associated with specif... more This study evaluated the effect of a novel formulation for starter culture associated with specific ripening conditions (NoNit TM technology) vs. a commercial» starter on the fate of selected pathogens and hygiene indicators during the fermentation and ripening of experimentally spiked salame nostrano (Italian dry sausage). Selected strains of Staphylococcus aureus 27R, Escherichia coli CSH26 K 12, Listeria innocua ATCC 33090 and Salmonella Derby 27 were inoculated into salami batter and challenged with two formulations of starter cultures (a commercial formulation and the NoNit™ formulation, consisting of Lactococcus lactis ssp. lactis, strain 340; L. lactis ssp. lactis, strain 16; Lactobacillus casei ssp. casei, strain 208 and Enterococcus faecium strain 614) with ripening at a low temperature. The proposed technology (NoNit™) performed better than the commercial formulation and limited the growth of spiked Escherichia coli, Staphylococcus aureus (including the production of enterotoxin), Salmonella Derby and Listeria innocua, yet maintained the basic product appearance and texture.
Journal of the South African Veterinary Association
Toxins
Shiga-toxin-producing Escherichia coli is a foodborne pathogen commonly associated with human dis... more Shiga-toxin-producing Escherichia coli is a foodborne pathogen commonly associated with human disease characterized by mild or bloody diarrhea hemorrhagic colitis and hemolytic uremic syndrome. This study investigated the occurrence of STEC in fecal samples of 289 goats in South Africa using microbiological culture and PCR. Furthermore, 628 goat STEC isolates were characterized by serotype (O:H) and major virulence factors by PCR. STEC was found in 80.2% (232/289) of goat fecal samples. Serotyping of 628 STEC isolates revealed 63 distinct serotypes including four of the major top seven STEC serogroups which were detected in 12.1% (35/289) of goats: O157:H7, 2.7% (8/289); O157:H8, 0.3%, (1/289); O157:H29, 0.3% (1/289); O103:H8, 7.6% (22/289); O103:H56, 0.3% (1/289); O26:H2, 0.3% (1/289); O111:H8, 0.3% (1/289) and 59 non-O157 STEC serotypes. Twenty-four of the sixty-three serotypes were previously associated with human disease. Virulence genes were distributed as follows: stx1, 60.6% ...
Characterization of important non-O157 verotoxin-producing Escherichia coli (VTEC) has lagged con... more Characterization of important non-O157 verotoxin-producing Escherichia coli (VTEC) has lagged considerably behind that of O157:H7 strains. This study characterized 91 VTEC O103:H2 strains from bovine and human sources and of North American and European origins by virulence or putative virulence genes, pulsed-field gel electrophoresis (PFGE) patterns, plasmid profiles, antimicrobial resistance, and colicin production. All strains were positive for vt1 and eae-ɛ; 97% were positive for ehxA; and all were negative for hlyA. Two strains carried vt2. There were 66 PFGE patterns grouped in six clusters, and there were 25 different plasmid profiles. Plasmid-encoded katP and etp genes were significantly more frequent in European than in North American human strains. The distribution of selected phenotypes was as follows: enterohemorrhagic E. coli (EHEC) hemolysin, 95%; colicin production, 38%; antimicrobial resistance, 58%. All the strains were negative for the alpha-hemolytic phenotype. In ...
Italian Journal of Food Safety
The latest EU regulation on geographical indications (EU Regulation No. 1151/2012) has introduced... more The latest EU regulation on geographical indications (EU Regulation No. 1151/2012) has introduced a set of new tools for the protection and enhancement of food products in rural areas, under the group name of optional quality term (OQT). The Commission Delegated EU Regulation, No. 665/2014, regulated the conditions for the use of the optional quality term mountain product (MP), to support the implementation of a mountain value chain. This new tool is aimed at promoting local development, maintaining the economic activities in mountain areas, and redistributing wealth, whilst, at the same time, promoting the territory. Pecorino and goat cheeses are typical Italian cheeses made usually with whole raw ewe’s or raw goat’s milk, without starter culture addition. In an attempt to characterize these productions, the aim of this study was to investigate the evolution of enterococci during the production and ripening of Pecorino cheese made in three different farms, located in Umbria, Italy ...
Microbiology Research
Enterococci have become major nosocomial pathogens. An increasing number of these infections are ... more Enterococci have become major nosocomial pathogens. An increasing number of these infections are as a result of vancomycin-resistant enterococci. Accurate detection of vancomycin-resistant enterococci (VRE) is important, so that appropriate therapy and infection control measures may be instituted, including veterinary surveillance. Two screening assays to detect vancomycin resistance in enterococci are proposed. Barnes Basal Medium agar (Ba) and Brain Heart Infusion (BHI) broth (plus 1% TTC-2,3,5-triphenyltetrazolium chloride) with several concentrations of vancomycin were used in this work. Five Enterococcus casseliflavus strains with low-level resistance to vancomycin (4 µg/mL) were used. Both media were able to quickly detect the breakpoint of the vancomycin-resistant strains used in this work, and also provided insight into the dynamics of the antibiotic effect at a low concentration on the tested bacterial suspensions.
Animals, 2021
The immediate refrigeration of meat after slaughter is a key issue for the proper storage and agi... more The immediate refrigeration of meat after slaughter is a key issue for the proper storage and aging of meat. The industry standard cold chain relies on low temperatures and ventilation to lower the internal carcass temperature to 0–4 °C within the first 48 h, i.e., within four times the so-called semi-cooling time. On the other hand, for games, once bled and eviscerated, the carcass must be sent to a point where it can be sectioned or kept on air for maturation at refrigeration temperature. The precautions to observe are few and simple but essential: protect the meat and start the cooling process quickly. After preparing the animal (bleeding and evisceration), it may be necessary to face a period of transport that is sometimes long and not very easy; while small animals can be easily transported in a backpack, larger ones must necessarily be carried by several people or sometimes dragged to the vehicle capable of transporting them. It is obvious that a wild boar opened from the jaws...
Journal of Dairy Research, 2021
In this research communication we report on the diversity of yeast and mould species in 69 sample... more In this research communication we report on the diversity of yeast and mould species in 69 samples of milk and different dairy products from three plants located in Umbria, central Italy. Isolates were characterised both macroscopically and microscopically and then identified by PCR and genome sequencing of the ITS region and the D1–D2 domain of the large-subunit rRNA gene for filamentous fungi and yeasts, respectively. Out of the 69 samples analysed, 51 (73.9%) tested positive for the presence of yeasts, whereas moulds were detected in 25 (36.2%) samples. A total of 9 yeast species belonging to 8 different genera and 13 mould species belonging to 6 different genera were isolated. The most common genera isolated were Debaryomyces and Kluyveromyces among the yeasts and Penicillium and Galactomyces among the moulds. Microbiota play a key role in the formation of flavour, aroma, texture and appearance of dairy products. This complex microbial ecosystem includes both cultured and extern...
These data present the results and data underlying the figures of the related study - <i>Co... more These data present the results and data underlying the figures of the related study - <i>Contaminated feed-borne Bacillus cereus aggravates respiratory distress post avian influenza virus H9N2 infection by inducing pneumonia</i> - in which the humoral and mucosal responses of specific-pathogen-free (SPF) chickens to <i>Bacillus cereus</i> and avian influenza A subtype H9N2 coinfection were evaluated.<br>Data are presented in an XLSX file and are arranged based on their associated figure and specific panel therein from the accompany paper. Data are further grouped based on the 5 study groups observed:<br>* SPF chicks inoculated with <i>B. cereus</i> followed by H9N2 (n=21)* SPF chicks inoculated with H9N2 followed by <i>B. cereus </i>(n=21)* SPF chicks inoculated with <i>B. cereus </i>only (n=21)* SPF chicks inoculated with H9N2 only (n=21)* Control (n=21)<br>The contents of the data provided are listed bel...
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Papers by Musafiri Karama