Survival of Escherichia coli O157:H7 during the manufacture and ripening of Cacioricotta goat cheese

F Ioanna; N C Quaglia; M M Storelli; D Castiglia; E Goffredo; A Storelli; M De Rosa; G Normanno; A Caputi Jambrenghi; A Dambrosio

doi:10.1016/j.fm.2017.10.005

Survival of Escherichia coli O157:H7 during the manufacture and ripening of Cacioricotta goat cheese

Food Microbiol. 2018 Apr:70:200-205. doi: 10.1016/j.fm.2017.10.005. Epub 2017 Oct 23.

Authors

F Ioanna¹, N C Quaglia², M M Storelli³, D Castiglia¹, E Goffredo⁴, A Storelli³, M De Rosa⁵, G Normanno⁶, A Caputi Jambrenghi⁷, A Dambrosio⁸

Affiliations

¹ Department of Emergency and Organ Transplantation, Section of Veterinary Clinic and Animal Production, University of Bari Aldo Moro, Strada Prov.le per Casamassima, Km 3, 70010 Valenzano, Bari, Italy.
² Department of Veterinary Medicine, University of Bari Aldo Moro, Strada Prov.le per Casamassima, Km 3, 70010 Valenzano, Bari, Italy.
³ Department of Biosciences, Biotechnologies and Biopharmaceutical, University of Bari Aldo Moro, Strada Prov.le per Casamassima, Km 3, 70010 Valenzano, Bari, Italy.
⁴ Institute Zooprofilattico of Apulia and Basilicata, Via Manfredonia, 20, 71121 Foggia, Italy.
⁵ Veterinary Surgeon, Freelance Professional, Via Martiri di via Fani, 62, 70025 Grumo Appula, Bari, Italy.
⁶ Department of Science of Agricolture, Food and the Environment, University of Foggia, Via A. Gramsci, 89/91, 71122 Foggia, Italy.
⁷ Department of Agricultural and Environmental Science, University of Bari Aldo Moro, University campus "Ernesto Quagliariello", Via Orabona, 4, 70125 Bari, Italy.
⁸ Department of Emergency and Organ Transplantation, Section of Veterinary Clinic and Animal Production, University of Bari Aldo Moro, Strada Prov.le per Casamassima, Km 3, 70010 Valenzano, Bari, Italy. Electronic address: angela.dambrosio@uniba.it.

PMID: 29173628
DOI: 10.1016/j.fm.2017.10.005

Abstract

The aim of this study was to assess the growth and survival of Escherichia coli O157:H7 during the manufacturing and ripening of Cacioricotta goat cheese. Goat milk was artificially contaminated with E. coli O157:H7 and the bacterial load was monitored from production up to 90 days of ripening. Goat milk was inoculated with 10² cfu ml^-1 of E. coli O157:H7 and the bacterial count of the curd at time zero was 2.31 log₁₀ cfu g^-1. During the first day of ripening, the bacterial load has increased to 5.73 log₁₀ cfu g^-1 to more than 6.20 log₁₀ cfu g^-1 during the first week. The bacterial load remained constant up to 28 days and then slightly decreased until the end of ripening, with values of a_w and pH of 0.88 and 5.41 respectively. The results of this study highlighted that E. coli O157:H7 is able to survive the manufacturing process and they suggest that the 90-day period of ripening alone is insufficient to remove E. coli O157:H7 in contaminated Cacioricotta goat cheese. Moreover, these results support the assumption that the presence of a low contamination of milk with E. coli O157:H7 could represent a potential source of infection and a threat to consumers.

Keywords: Cacioricotta goat cheese; Challenge test; Escherichia coli O157:H7; Goat milk cheese.

MeSH terms

Animals
Cheese / analysis
Cheese / microbiology*
Escherichia coli O157 / genetics
Escherichia coli O157 / growth & development*
Escherichia coli O157 / isolation & purification
Food Contamination / analysis*
Food Handling
Goats
Microbial Viability
Milk / microbiology