ABSTRACT
Fiore Sardo is a Protected Designation of Origin (PDO) cheese produced in Sardinia (Italy) from raw sheep's milk, presenting risk factors due to an accumulation of Biogenic Amines (BA). A total of 37 Fiore Sardo cheese samples produced in 19 dairy farms were collected from local retail stores to evaluate BA content and its relationship with free amino acids (FAA) and composition. The following were determined for each sample: pH, water activity, composition (moisture, dry matter, NaCl, protein and fat content). FAA and BA, after extraction, were determined by HPLC-FL. The total BA content in Fiore Sardo PDO cheese samples was 127±87 mg 100 g-1, ranging between 6 and 366 mg 100 g-1. Tyramine showed the highest concentration (82±51 mg 100 g-1), followed by putrescine (21±26 mg 100 g-1). Moreover, cadaverine, histamine, ß-phenylethylamine and tryptamine were detected at concentrations lower than 10 mg 100 g-1. Overall 54% of the samples analysed exceeded the threshold of 90 mg 100 g-1 for total BA content, posing a potential risk for consumers. BA, total FAA (2233±764 mg 100 g-1) and pH were positively correlated (P≤0.01) between themselves, whereas BA content was not correlated with aw, humidity and percentage of NaCl. The hierarchical cluster analysis results, considering 37 samples and 6 variables, detected four different groups. Samples with BA ≥200 mg 100 g-1 were distributed in two groups characterized by a higher proteolysis indicator levels (FAA, pH) but significantly different for aw, humidity and NaCl concentration. The results showed that high levels of BA were detectable in some samples of Fiore Sardo PDO cheese, suggesting that effective technological conditions at production should be adopted.
ABSTRACT
In the last years changes occurred in the production process of ricotta mustia, a traditional smoked, salted and sometimes ripened ricotta cheese, produced in Sardinia. Fresher, slightly smoked and with reduced salt content products, were introduced into the market to meet changes in consumer's preferences for milder products. The present study of durability was conducted on an innovative fresh and smoked industrial product, also characterized by the small size and the packaging in modified atmosphere. A durability test to assess the evolution of microbiological and physicochemical profile of the product stored at refrigeration (4°C) and mild abuse (7°C) temperatures was carried out. A total of 126 ricotta samples smoked for either 1, 2, or 3 h were analyzed at intervals during shelflife for the determination of aerobic mesophilic counts, Enterobacteriaceae, yeast, moulds, L. monocytogenes, Pseudomonas spp. and B. cereus. Intrinsic properties, physic-chemical and headspace gas composition were also analyzed. Average and standard deviation were respectively 6,06±0,22 for pH, 0,982±0,05 for aW, 74,67%±1,81% for moisture, 10,25%±1,35% for fat, 10,92%±0,46% for protein and 1,70%±0,42% for salt content. Total bacterial count ranged between 3.88±0.48 log cfu/g at T0 and 3.25±1.02 at T45. L. monocytogenes, Pseudomonas spp. and E. coli were always below the detection limit. Enterobacteriaceae prevalence (percentage) was 3.17% (2.62±0.42 lg10 cfu/g) and was limited to samples stored longer than 30 days while B. cereus was recovered in 5.55% (2.36±0.35 lg10 cfu/g) of the samples and was never observed in samples after 45 days of refrigerated storage. The durability study is preliminary to challenge test to assess the shelf-life of this product in compliance with the requirements of Regulation (EC) 2073/2005.
ABSTRACT
In the present work the results of a survey conducted in Sardinia Region on Aflatoxin M1 (AFM1) contamination in milk of small ruminants from 2005 to 2013 are reported. A total of 517 sheep and 88 goat milk samples from bulk tank, tank trucks and silo tank milk were collected. Analyses were performed by the Regional Farmers Association laboratory using high-performance liquid chromatography following the ISO 14501:1998 standard. None of the sheep milk samples analysed during 2005-2012 showed AFM1 contamination. In sheep milk samples collected in 2013, 8 out of 172 (4.6%) were contaminated by AFM1 with a concentration (mean±SD) of 12.59±14.05 ng/L. In one bulk tank milk sample 58.82 ng/L AFM1 was detected, exceeding the EU limit. In none of goat milk samples analysed from 2010 to 2012 AFM1 was detected. In 2013, 9 out of 66 goat milk samples (13.6%) showed an AFM1 concentration of 47.21±19.58 ng/L. Two of these samples exceeded the EU limit, with concentrations of 62.09 and 138.6 ng/L. Higher contamination frequency and concentration rates were detected in bulk tank milk samples collected at farm than in bulk milk truck or silo samples, showing a dilution effect on AFM1 milk content along small ruminants supply chain. The rate and levels of AFM1 contamination in sheep and goat milk samples were lower than other countries. However, the small number of milk samples analysed for AFM1 in Sardinia Region in 2005-2013 give evidence that food business operators check programmes should be improved to ensure an adequate monitoring of AFM1 contamination in small ruminant dairy chain.
