Occurrence and behavior of Bacillus cereus in naturally contaminated ricotta salata cheese during refrigerated storage

Spanu, Carlo; Scarano, Christian; Spanu, Vincenzo; Pala, Carlo; Casti, Daniele; Lamon, Sonia; Cossu, F; Ibba, Michela; Nieddu, Gavino; Santis, E.P.L. De

doi:10.1016/j.fm.2016.05.002

Cited by 31 publications

(27 citation statements)

References 23 publications

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“…16% of the samples analysed with a viable count of 3.79±0.95 Log CFU/g. This results was similar to previously reported by Cosentino et al ( 1997 ) who studied the incidence and biochemical characteristics of Bacillus flora in Sardinian dairy products, but lower than those reported by Spanu et al ( 2016 ) in ricotta salata cheese analyzed after 24 h from production (t 0 ). However, the level of contaminations did not reach the threshold that leads to significant toxin production (EFSA 2016 ).…”

Section: Resultssupporting

confidence: 92%

Retrospective study on the hygienic quality of fresh ricotta cheeses produced in Sicily, Italy

Scatassa¹,

Mancuso²,

Sciortino³

et al. 2018

Ital J Food Safety

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The present work was carried out to investigate the microbiological profile of Sicilian ewes’ ricotta cheeses during fifteen years of investigations (2002-2016). The samples were collected between those conferred to the Istituto Zooprofilattico Sperimentale della Sicilia (IZSSi) Adelmo Mirri, Palermo (Italy), by the competent authority during official control, by food business operator in HACCP systems and in research projects. Enterobacteriaceae, Escherichia coli and coagulase-positive staphylococci (CPS) were found only in some samples. Bacillus cereus was detected in c.a. 16% of samples but the level of contaminations did not reach the threshold that leads to significant toxin production. Pathogenic bacteria such as Listeria monocytogenes, Salmonella spp. and Brucella spp. were never detected. Furthermore, a total of 47 of lactic acid bacteria (LAB) strains were identified at species level by sequencing the 16S rRNA gene, resulting in the identification of 10 species belonging to four genera Enterococcus, Lactobacillus, Lactococcus and Leuconostoc, commonly employed as starter and non starter cultures in different traditional cheese. Results of this study highlighted an improvement of the hygienic conditions of the Sicilian ewes’ ricotta cheeses during the last ten years of investigation. This observation was confirmed from reduction of undesired microorganisms such as Enterobacteriaceae, E.coli and CPS, used to define the process hygiene criteria. However, in order to improve the final quality of this product are needed further strategy such as the dairy makers training, with the aim to apply a good hygienic practices during the production.

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Section: Resultssupporting

confidence: 92%

Retrospective study on the hygienic quality of fresh ricotta cheeses produced in Sicily, Italy

Scatassa¹,

Mancuso²,

Sciortino³

et al. 2018

Ital J Food Safety

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show abstract

“…In this context, it was shown that fatty acids from foods enhance growth of B. cereus under cold and anaerobic conditions [184]. On the other hand, some foods and conditions seem not to favour sporulation, germination or growth (refrigerated ricotta salata cheese or tofu [174,175,185]).…”

Section: Prevalence and Survival Of B Cereus In Foodsmentioning

confidence: 99%

The Bacillus cereus Food Infection as Multifactorial Process

Jeßberger

Dietrich

Granum

et al. 2020

Toxins

122

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The ubiquitous soil bacterium Bacillus cereus presents major challenges to food safety. It is responsible for two types of food poisoning, the emetic form due to food intoxication and the diarrheal form emerging from food infections with enteropathogenic strains, also known as toxico-infections, which are the subject of this review. The diarrheal type of food poisoning emerges after production of enterotoxins by viable bacteria in the human intestine. Basically, the manifestation of the disease is, however, the result of a multifactorial process, including B. cereus prevalence and survival in different foods, survival of the stomach passage, spore germination, motility, adhesion, and finally enterotoxin production in the intestine. Moreover, all of these processes are influenced by the consumed foodstuffs as well as the intestinal microbiota which have, therefore, to be considered for a reliable prediction of the hazardous potential of contaminated foods. Current knowledge regarding these single aspects is summarized in this review aiming for risk-oriented diagnostics for enteropathogenic B. cereus.

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“…In fact, curd can represent a suitable substrate for B. cereus to replicate and potentially reach counts of concern. It is arguable that the early addition of pro-technological starter cultures (Lactobacillus bulgaricus and Streptococcus thermophilus) coupled with curd and cheese salting contrast the growth of microbial contaminants during the first drying and ripening phases of Taleggio cheese, as observed for other dairy products [5,[25][26][27][28]. In this light, B. cereus contamination of the brining vat could be This study analyzed the degree of diffusion of B. cereus in the Taleggio production environment, considering a plant typology where all the phases (production and ripening) are performed following the PDO standard.…”

Section: Virulence Potential Of B Cereus Isolatesmentioning

confidence: 99%

“…Spore forming bacteria are still a challenge in dairy processing plants in terms of dairy product safety and spoilage. In particular, Bacillus cereus is recognized as a common contaminant of dairy products with frequent isolation from raw and pasteurized milk [1][2][3], as well as from final products [4,5]. This microorganism was also proven able to replicate in some dairy products such as ricotta and mascarpone cheese [6,7].…”

Section: Introductionmentioning

confidence: 99%

Identification and Pathogenic Potential of Bacillus cereus Strains Isolated from a Dairy Processing Plant Producing PDO Taleggio Cheese

et al. 2020

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Low levels of contamination by Bacillus cereus at the cheese farm is essential for reducing any opportunity for growth prior consumption. In this study, B. cereus distribution in a plant producing Protected Designation of Origin Taleggio cheese was investigated and the virulence potential of the isolates was evaluated. Seventy-four samples were collected from Food and Non Food Contact Surfaces (FCS, NFCS), saline curd, and Taleggio. The eleven isolates were identified, typified, and clustered. Strains were tested for the production of hemolysins, hemolysin BL (HBL), phosphatidylcholine-specific phospholipase C (PC-PLC), proteases, and biofilm, and for the presence of chromosomal toxin-encoding genes (sph, plcA, cytK, entFM, bcet, entS, nheA, nheB, nheC). B. cereus was detected on NFCS, FCS, and curd, but not in Taleggio. The isolates were grouped into six clusters, and all produced PC-PLC, hemolysins, and proteases, and most of them HBL (66.7%). All the clusters harbored the nheA, sph, plcA, entFM, and cytK genes, and some also nheB (83.3%), nheC (66.7%), bcet (50.0%), and entS (66.7%). All strains showed biofilm-forming ability. Our data reveal possible contamination of production plants and cheese curd by potentially virulent B. cereus, but bacterial absence in Taleggio highlights the efficacy of a proper management of the production phases in assuring consumer’s protection.

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Occurrence and behavior of Bacillus cereus in naturally contaminated ricotta salata cheese during refrigerated storage

Cited by 31 publications

References 23 publications

Retrospective study on the hygienic quality of fresh ricotta cheeses produced in Sicily, Italy

Retrospective study on the hygienic quality of fresh ricotta cheeses produced in Sicily, Italy

The Bacillus cereus Food Infection as Multifactorial Process

Identification and Pathogenic Potential of Bacillus cereus Strains Isolated from a Dairy Processing Plant Producing PDO Taleggio Cheese

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