Serbian Traditional Goat Cheese: Physico-Chemical, Sensory, Hygienic and Safety Characteristics

This research project aimed to investigate the physico-chemical, sensory, hygienic and safety characteristics of raw goat milk, whey, brine and traditional goat cheese during the ripening period of 28 days. Physico-chemical parameters included the determination of dry matter, fat, ash, protein, pH, water activity and NaCl content. The presence of Enterobacteriaceae and fungi was estimated on milk and cheese samples, and a sensory panel evaluated the products’ features and acceptability during ripening. The results show that the cheese under study belongs to the acid full-fat cheese group. A consumer panel attributed high scores to the goat cheese, until the 21st day of ripening. After this period, the overall features altered significantly, including augmented bitterness, odor intensification and the development of molds on the surface. The presence of fungi, associated with Enterobacteriaceae, suggests that the hygiene of the production processes needs to be improved. Regarding microbial safety, the detection of putative pathogens and antibiotic resistances recommend an active surveillance of traditional foods to avoid foodborne infections and/or the dissemination of resistant microorganisms along the food chain.

Microbial Load and Antibiotic Resistance of Escherichia coli and Staphylococcus aureus Isolated from Ready-to-Eat (RTE) Khebab Sold on a University Campus and Its Environs in Ghana

The demand for ready-to-eat (RTE) foods is handy to busy urban dwellers. Handling, processing, and selling are known to contaminate these foods and cause foodborne outbreaks. This study assessed a load of S. aureus and E. coli in khebabs (beef, chevon, and gizzard) sold on the KNUST campus and its environs and how resistant they are to clinically relevant antimicrobial agents. Thirty-six (36) khebab samples were purchased from vendors at Kotei, Ayeduase, Kentinkrono, Boadi, KNUST campus, and Ayigya. They were analyzed for S. aureus and E. coli and their resistance to clinically relevant antimicrobial agents checked using standard methods. S. aureus and E. coli load ranged from 4.09 to 5.96 CFU/g and 1.79 to 6.12 MPN/g in beef, 4.02 to 6.01 CFU/g and 1.99 to 4.44 MPN/g in chevon, and 5.37 to 6.18 CFU/g and 1.79 to 6.10 MPN/g in gizzard khebabs in the different locations. E. coli (n = 27) were multiresistant to ampicillin, tetracycline, gentamicin, cefuroxime, ceftriaxone, cefotaxime, and cotrimoxazole (51.85%) and susceptible to chloramphenicol (100%). S. aureus (n = 36) isolates were multiresistant to penicillin, tetracycline, flucloxacillin, cefuroxime, ampicillin (97.22%), erythromycin (75%), cotrimoxazole (86.11%), and gentamicin (69.44%). It can therefore be concluded that the majority of khebabs from the KNUST campus and its environs were contaminated with S. aureus and E. coli above the acceptable standard limits (≤4 log10 CFU/g and ˂2 log10MPN/g, respectively). Also, the S. aureus and E. coli isolated were multiresistant to the antibiotics tested and could be a medium for the transmission of antibiotic-resistant bacteria and therefore expose consumers to a high risk of contracting foodborne infections with drug-resistant strains.

Comparing gut resistome composition among patients with acute Campylobacter infections and healthy family members

Campylobacter commonly causes foodborne infections and antibiotic resistance is an imminent concern. It is not clear, however, if the human gut ‘resistome’ is affected by Campylobacter during infection. Application of shotgun metagenomics on stools from 26 cases with Campylobacter infections and 44 healthy family members (controls) identified 406 unique antibiotic resistance genes (ARGs) representing 153 genes/operons, 40 mechanisms, and 18 classes. Cases had greater ARG richness (p < 0.0001) and Shannon diversity (p < 0.0001) than controls with distinct compositions (p = 0.000999; PERMANOVA). Cases were defined by multidrug resistance genes and were dominated by Proteobacteria (40.8%), specifically those representing Escherichia (20.9%). Tetracycline resistance genes were most abundant in controls, which were dominated by Bacteroidetes (45.3%) and Firmicutes (44.4%). Hierarchical clustering of cases identified three clusters with distinct resistomes. Case clusters 1 and 3 differed from controls containing more urban and hospitalized patients. Relative to family members of the same household, ARG composition among matched cases was mostly distinct, though some familial controls had similar profiles that could be explained by a shorter time since exposure to the case. Together, these data indicate that Campylobacter infection is associated with an altered resistome composition and increased ARG diversity, raising concerns about the role of infection in the spread of resistance determinants.

Salmonella - foodborne pathogen and antimicrobial resistance

Foodborne diseases encompass a wide spectrum of illnesses and are a growing public health problem worldwide. They are caused by consumption of food or water contaminated by pathogenic (disease-causing) microorganisms such as bacteria, viruses and parasites. The contamination of food can occur at any stage in the process from food production to consumption (“farm to fork”) and can result from environmental contamination (water, soil or air). They enter the body through the gastrointestinal tract where the first symptoms often occur like nausea, vomiting, stomach cramps, and diarrhoea. However, symptoms differ among the different types of foodborne diseases and the patient’s immune status. Symptoms can sometimes be severe and some foodborne illnesses can even be fatal. Commonly recognized foodborne infections are: campylobacteriosis, Escherichia coli O157:H7 infection and haemolytic uremic syndrome (HUS), salmonellosis, cryptosporidiosis, listeriosis, giardiasis. norovirus infection, scombroid fish poisoning, shigellosis, toxoplasmosis, Vibrio infection and yersiniosis. One of the top three germs that cause illnesses from food eaten in EU is Salmonella.

Can Human Handling Increase the Presence of Multidrug Resistance (MDR) in Salmonella spp. Isolated from Food Sources?

The spread of antibiotic resistance (AR) among zoonotic pathogens is a serious health problem, especially because in the last decade the massive use of antibiotics has favored the emergence of Multidrug Resistance (MDR) strains. Some species of the Salmonella genus are among the major causes of foodborne infections worldwide and could represent reservoirs of AR. For these reasons, the susceptibility to six antibiotic classes of 63 strains isolated from animals and food was determined to assess the presence of MDR strains. In addition, the detection of resistance genes was done for strains that resulted in MDR. A statistically significant difference was found when comparing the presence of Salmonella spp. MDR strains between strains isolated from animals and strains isolated from food. Our data seem to indicate that MDR occurs mostly in Salmonella strains isolated from food.

Microbial Exposure Assessment of Fresh and Smoked Pork Meat within Ado-Ekiti Metropolis, Nigeria

The breeding and production environments of pigs tend to be exposed to microbial contaminations and could portend a potential public health hazard if not well managed. This study investigated bacterial and fungal loads of commercial fresh and smoked pork in order to ascertain their wholesomeness. Total aerobic bacterial and fungal count were done on nutrient agar and potato dextrose agar respectively, while antimicrobial susceptibility test to selected commercial antibiotic discs carried out using Disk Diffusion Technique. All the twenty samples (Fresh and Smoked) cultured yielded bacterial growth with a range of 2.2 - 9.0 × 104 CFU/g (smoked) to 1.0 – 6.3 × 106 CFU/g (fresh). On the other hand, the fungal loads ranges from 1.0 – 6.0 × 102 CFU/g(smoked) to 1.0 -5.0 × 104 CFU/g (fresh). The bacterial isolated and the ratios in fresh and smoked samples wereStaphylococcus aureus (6: 11), Escherichia coli (5: 8), Bacillus cereus (4: 7), Salmonella spp. (2: 3), Proteus spp. (0: 4), Enterobacter spp. (1: 2), Shigella spp. (0:2) and Pseudomonas aeruginosa (1: 0), while their fungal counterpart included Aspergillus niger (4: 2), Aspergillus terreus (2; 2),Fusarium oxysporum(4: 0), Penicillium spp. (4: 2), Rhizopus spp. (3: 5), Mucor spp. (0: 4); Geotricum candidum (0: 2) and Microsporium spp. (0: 2). Most of the S.aureus (> 58.8%) and P. aeruginosa (100%), and B. cereus (100%) demonstrated remarkable resistance to the majority of the tested antibiotics. These findings are of public health concern because most of the bacterial and fungal isolates have been implicated in foodborne infections. Hence, there is a need for stricter sanitary measures during the rearing and production to reduce the level of microbial contaminations.

Development of a Tetraplex qPCR for the Molecular Identification and Quantification of Human Enteric Viruses, NoV and HAV, in Fish Samples

Human enteric viruses such as norovirus (NoV) and hepatitis A virus (HAV) are some of the most important causes of foodborne infections worldwide. Usually, infection via fish consumption is not a concern regarding these viruses, since fish are mainly consumed cooked. However, in the last years, raw fish consumption has become increasingly common, especially involving the use of seabass and gilthead seabream in dishes like sushi, sashimi, poke, and carpaccio. Therefore, the risk for viral infection via the consumption of raw fish has also increased. In this study, a virologic screening was performed in 323 fish specimens captured along the Portuguese coast using a tetraplex qPCR optimised for two templates (plasmid and in vitro transcribed RNA) to detect and quantify NoV GI, NoV GII and HAV genomes. A difference of approximately 1-log was found between the use of plasmid or in vitro transcribed RNA for molecular-based quantifications, showing an underestimation of genome copy-number equivalents using plasmid standard-based curves. Additionally, the presence of NoV genomic RNA in a pool of seabass brains was identified, which was shown to cluster with a major group of human norovirus sequences from genogroup I (GI.1) by phylogenetic analysis. None of the analysed fish revealed the presence of NoV GII or HAV. This result corroborates the hypothesis that enteric viruses circulate in seawater or that fish were contaminated during their transportation/handling, representing a potential risk to humans through raw or undercooked fish consumption.

Prevalence of 16S rRNA Methylation Enzyme Gene armA in Salmonella From Outpatients and Food

Salmonella is the primary cause of community-acquired foodborne infections, so its resistance to antimicrobials, such as aminoglycosides, is a public health issue. Of concern, aminoglycoside resistance in Salmonella is increasing rapidly. Here, we performed a retrospective study evaluating the prevalence of Salmonella harboring armA-mediated aminoglycoside resistance in community-acquired infections and in food or environmental sources. The prevalence rates of armA-harboring Salmonella strains were 1.1/1,000 (13/12,095) and 8.7/1,000 (32/3,687) in outpatient and food/environmental isolates, respectively. All the armA-harboring Salmonella strains were resistant to multiple drugs, including fluoroquinolone and/or extended-spectrum cephalosporins, and most (34/45) belonged to serovar Indiana. The armA gene of these strains were all carried on plasmids, which spanned five replicon types with IncHI2 being the dominant plasmid type. All the armA-carrying plasmids were transferable into Escherichia coli and Acinetobacter baumannii recipients. The conjugation experiment results revealed that the armA-harboring S. Indiana strains had a relatively higher ability to acquire armA-carrying plasmids. The low similarity of their pulsed field gel electrophoresis patterns indicates that the armA-harboring Salmonella strains were unlikely to have originated from a single epidemic clone, suggesting broad armA spread. Furthermore, the genetic backgrounds of armA-harboring Salmonella strains isolated from outpatients exhibited higher similarity to those isolated from poultry than to those isolated from swine, suggesting that poultry consumption maybe an infection source. These findings highlight an urgent need to monitor the prevalence and transmission of armA-harboring Salmonella, especially S. Indiana, to better understand the potential public health threat and prevent the further spread of these strains.