Ensuring microbiological safety in the food (of animal origin) chain is a challenging task due to the complex interactions among animals, humans and the environment. However, technological and ...analytical advances in recent years have provided a broader insight into microbiological hazards in the food chain and risk assessment. The objective of the proposed Special Issue “Study of Microbiological Safety in the Food Chain” was therefore to obtain scientific papers addressing microbiological hazards in the food chain, such as bacterial antimicrobial resistance, bacterial or fungal spoilage of foods, the antimicrobial potential of the indigenous microbiota, the aminogenic or amine-reducing capacity of the microbiota, and papers that apply novel methods to study the food microbiome to discover potential, previously unknown microbial hazards. This Special Issue of the journal Processes entitled “Study of Microbiological Safety in the Food Chain” consists of nine research papers and one review paper. Four papers focus on the microbiological aspects of milk and dairy products, three on meat and meat products, two on eggs, and one on various market foods. The microorganisms of interest were species of lactobacilli, enterococci and molds, Yersinia enterocolitica, Bacillus cereus and the general microbiota in certain foods.
The aim of this study was to identify and compare surface mycobiota of traditional and industrial Croatian dry-fermented sausage
, especially toxicogenic species, and to detect contamination with ...mycotoxins recognized as the most important for meat products. Identification of mould species was performed by sequence analysis of beta- tubulin and calmodulin gene, while the determination of mycotoxins aflatoxin B
(AFB
), ochratoxin A (OTA), and cyclopiazonic acid (CPA) was carried out using the LC-MS/MS (liquid chromatography-tandem mass spectrometry) method. The results showed a significantly higher number of mould isolates and greater species (including of those mycotoxigenic) diversity in traditional
samples in comparison with the industrial ones.
, as a potential CPA-producer, was the most represented in traditional
(19.0%), followed by
(16.6%), which was the most represented in industrial
samples (23.8%). The results also showed that 69% of the traditional sausage samples were contaminated with either CPA or OTA in concentrations of up to 13.35 µg/kg and 6.95 µg/kg, respectively, while in the industrial samples only OTA was detected (in a single sample in the concentration of 0.42 µg/kg). Mycotoxin AFB
and its producers were not detected in any of the analysed samples (<LOD).
The aim of the study was to evaluate the antimicrobial activity of the extracted plants basil (Ocimum basilicum L.), sage (Salvia officinalis L.), lavender (Lavandula officinalis L.), immortelle ...(Helichrysum italicum (Roth) G. Don), savory (Satureja montana L.), and rosemary (Salvia rosmarinus Spenn.) against foodborne and clinical pathogens. Dried plants were used in the production of Dalmatian cow’s milk hard cheese at concentrations of 0.5, 1.0, 1.5, and 2% to evaluate the microbiological safety and sensory properties of novel cheeses. The broadest antimicrobial activity was found in rosemary and sage, inhibiting ten indicator pathogens, and the strongest antimicrobial activity was found in immortelle and sage, which showed the widest zones of inhibition. The most sensitive indicators were Staphylococcus species and Yersinia enterocolitica. The supplemented cheeses met the official microbiological criteria and were mycotoxin negative. The surface mycobiota of control and experimental cheeses consisted mainly of Penicillium sollitum, based on the sequence analysis of the beta-tubulin and calmodulin genes. The antifungal effect of the added plants was clearly demonstrated in cheeses with added basil and sage (p < 0.05).
Interventions from lairage to the chilling stage of the pig slaughter process are important to reduce microbial contamination of carcasses. The aim of this systematic review and meta-analysis was to ...assess the effectiveness of abattoir interventions in reducing aerobic colony count (ACC), Enterobacteriaceae, generic Escherichia coli, and Yersinia spp. on pig carcasses. The database searches spanned a 30 year period from 1990 to 2021. Following a structured, predefined protocol, 22 articles, which were judged as having a low risk of bias, were used for detailed data extraction and meta-analysis. The meta-analysis included data on lairage interventions for live pigs, standard processing procedures for pig carcasses, prechilling interventions, multiple carcass interventions, and carcass chilling. Risk ratios (RRs) for prevalence studies and mean log differences (MDs) for concentration outcomes were calculated using random effects models. The meta-analysis found that scalding under commercial abattoir conditions effectively reduced the prevalence of Enterobacteriaceae (RR: 0.05, 95% CI: 0.02 to 0.12, I2 = 87%) and ACC (MD: −2.84, 95% CI: −3.50 to −2.18, I2 = 99%) on pig carcasses. Similarly, significant reductions of these two groups of bacteria on carcasses were also found after singeing (RR: 0.25, 95% CI: 0.14 to 0.44, I2 = 90% and MD: −1.95, 95% CI: −2.40 to −1.50, I2 = 96%, respectively). Rectum sealing effectively reduces the prevalence of Y. enterocolitica on pig carcasses (RR: 0.60, 95% CI: 0.41 to 0.89, I2 = 0%). Under commercial abattoir conditions, hot water washing significantly reduced ACC (MD: −1.32, 95% CI: −1.93 to −0.71, I2 = 93%) and generic E. coli counts (MD: −1.23, 95% CI: −1.89 to −0.57, I2 = 61%) on pig carcasses. Conventional dry chilling reduced Enterobacteriaceae prevalence on pig carcasses (RR: 0.32, 95% CI: 0.21 to 0.48, I2 = 81%). Multiple carcass interventions significantly reduced Enterobacteriaceae prevalence (RR: 0.11, 95% CI: 0.05 to 0.23, I2 = 94%) and ACC on carcasses (MD: −2.85, 95% CI: −3.33 to −2.37, I2 = 97%). The results clearly show that standard processing procedures of scalding and singeing and the hazard-based intervention of hot water washing are effective in reducing indicator bacteria on pig carcasses. The prevalence of Y. enterocolitica on pig carcasses was effectively reduced by the standard procedure of rectum sealing; nevertheless, this was the only intervention for Yersinia investigated under commercial conditions. High heterogeneity among studies and trials investigating interventions and overall lack of large, controlled trials conducted under commercial conditions suggest that more in-depth research is needed.
Yersinia enterocolitica is one of the priority biological hazards in pork inspection. Persistence of the pathogen, including strains resistant to antimicrobials, should be evaluated in pigs from ...different housing systems for risk ranking of farms. In this 2019 study, tonsils were collected from 234 pigs, of which 69 (29.5%) were fattened on 3 big integrated farms, 130 (55.5%) on 10 medium-sized farms, and 35 (15%) on 13 small family farms. In addition, 92 pork cuts and minced meat samples from the same farms were tested for the presence of Y. enterocolitica using the culture method. Phenotypic and genetic characteristics of the isolates were compared with previously collected isolates from 2014. The overall prevalence of Y. enterocolitica in pig tonsils was 43% 95% CI 36.7−49.7. In pigs from big integrated, medium-sized, and small family farms, the prevalence was 29%, 52%, and 40%, respectively. All retail samples of portioned and minced pork tested negative for pathogenic Y. enterocolitica, likely due to high hygienic standards in slaughterhouses/cutting meat or low sensitivity of culture methods in these matrices. The highest recovery rate of the pathogen from tonsils was found when alkali-treated PSB and CIN agar were combined. The biosecurity category of integrated and medium farms did not affect the differences in prevalence of Y. enterocolitica (p > 0.05), in contrast to family farms. Pathogenic ail-positive Y. enterocolitica biotype 4 serotype O:3 persisted in the tonsils of pigs regardless of the type of farm, slaughterhouse, and year of isolation 2014 and 2019. PFGE typing revealed the high genetic concordance (80.6 to 100%) of all the Y. enterocolitica 4/O:3 isolates. A statistically significant higher prevalence of multidrug-resistant Y. enterocolitica 4/O:3 isolates was detected in the tonsils of pigs from big integrated farms compared to the other farm types (p < 0.05), with predominant and increasing resistance to nalidixic acid, chloramphenicol, and streptomycin. This study demonstrated multidrug resistance of the pathogen in pigs likely due to more antimicrobial pressure on big farms, with intriguing resistance to some clinically relevant antimicrobials used in the treatment of yersiniosis in humans.
Ensuring microbiological safety in the food (of animal origin) chain is a challenging task due to the complex interactions among animals, humans and the environment ...
This study aimed to implement a microencapsulated form of selected autochthonous lactic-acid bacteria (LAB) isolated from the cheese-production chain and natural rennet obtained from suckling lambs ...in the traditional production of hard sheep cheese, “Paški sir”, from the island of Pag, Croatia. Two different formulations of microparticles were prepared: (i) microparticles containing the strain of both Lactiplantibacillus plantarum and Lactococcus lactis (S2) and (ii) microparticles containing both strains and natural rennet (S3). These formulations were used in the production of Paški sir cheese simultaneously with standard production using non-encapsulated commercial starter cultures and commercial rennet (S1). The number of Lc. lactis isolates decreased at day 30 and were not isolated during the remaining ripening process, whereas the number of L. plantarum remained stable throughout the ripening process. The level of LAB and the release of the rennet from microsphere formulations at the end allowed for the production of cheese with the same characteristics as the commercial product, indicating no negative interactions of natural rennet, bacterial culture, and chemical components of microparticles. To our knowledge, this is the first report of a microencapsulated L. plantarum (isolated from the abomasum of lambs) coupled with natural lamb’s rennet used in the production of hard sheep cheese. This pilot study showed the great potential for maintaining authenticity in cheese production by combining traditional and sustainable innovative technologies.
The aim of the present study was to evaluate the persistence of Listeria monocytogenes in raw milk from vending machines, based on culture and molecular detection of pathogen and Pulsed-Field Gel ...Electrophoresis typing. From December 2015 to January 2017, a total of 319 milk samples from 36 vending machines were examined for the presence and count of L. monocytogenes by reference methods ISO 11290:1 and ISO 11290:2. Molecular detection of pathogens was performed by loop-mediated isothermal DNA amplification (LAMP) coupled with bioluminescence (Molecular Detection Assay). L. monocytogenes was detected by MDA in 14 milk samples (4.38%) from four farms, compared to eight positive samples (2.5%) retrieved by a reference ISO method. Cultivable L. monocytogenes isolates were subjected to Pulsed-Field Gel Electrophoresis typing and pulsotypes were compared with those obtained during the previous survey in Croatia (2014‒2015). It was found that identical PFGE patterns of L. monocytogenes occur in milk samples of the same producer over a three-year period, indicating the persistence of pathogens in raw milk vending machines. The results obtained support the need for more effective control of milk in the entire food chain.
Cheeses as ready-to-eat food should be considered as a potential source of foodborne pathogens, primarily
The aim of present study was to determine the microbiological quality of soft, semi-hard and ...hard cheeses during the shelf-life, with particular reference to
Five types of cheeses were sampled at different time-points during the cold storage and analyzed for presence of
and
as well as lactic acid bacteria,
coagulase-positive staphylococci, yeasts, molds, sulfite-reducing clostridia and
counts. Water activity, pH and NaCl content were monitored in order to evaluate the possibility of
growth. Challenge test for
was performed in soft whey cheese, to determine the growth potential of pathogen during the shelf-life of product. All analyzed cheeses were compliant with microbiological criteria during the shelf-life. In soft cheeses, lactic acid bacteria increased in the course of the shelf-life period (1.2-2.6 log increase), while in semi-hard and hard cheeses it decreased (1.6 and 5.2 log decrease, respectively). Soft cheeses support the growth of
according to determined pH values (5.8-6.5), water activity (0.99-0.94), and NaCl content (0.3-1.2%). Challenge test showed that
growth potential in selected soft cheese was 0.43 log
cfu/g during 8 days at 4°C. Water activity in semi-hard and hard cheeses was a limiting factor for
growth during the shelf-life. Soft, semi-hard and hard cheeses were microbiologically stable during their defined shelf-life. Good manufacturing and hygienic practices must be strictly followed in the production of soft cheeses as
supporting food and be focused on preventing (re)contamination.
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