Semi-soft Cheese Research Articles

TRADITIONAL CHEESE PRODUCED IN FOGO ISLAND - CAPE VERDE: PHYSICO-CHEMICAL, SENSORY, HYGIENIC AND SAFETY CHARACTERISTICS

Cheese is a nutritionally rich product, distinguished by its unique sensorial qualities. Processing technology for cheeses in different countries is still handmade, thus, the microbial community structure is complex and the cheese flavour fluctuates wildly. Therefore, this study aimed to investigate the sensory acceptance, microbiological and physical-chemical properties of traditional cheese produced in Fogo Island – Cape Verde. Coalho cheese is the most produced and consumed cheese in Cape Verde and is frequently made according to traditional or artisanal procedures. Regarding to physical-chemical analyses, parameters such as fat, moisture, pH, titratable acidity, protein, and ash were studied. Microbiological parameters such as Escherichia coli, Listeria monocytogenes, salmonella and coliforms were studied. A Sensory acceptance test was carried out by 23 panellists, where all evaluated attributes obtained an acceptability index greater than 70%. According to the Cape Verdean standard for cheese, the cheeses were classified as fresh and low-fat cheese. Regarding moisture content, the obtained results allow to classify cheese A as semi-soft cheese and B and C as soft cheese. Concerning pH and titratable acidity, the values ranged from 5.68 to 6.19 and 6.4 to 11.1 mLNaOH1N/100g, respectively. Salmonella and L. monocytogenes were not detected, E. Coli was lower than the maximum accepted value established by Commission Regulation (EC) No 2073/2005 and Commission Regulation (EC) No 1441/2007. In contrast, faecal coliforms in cheeses B and C were higher than those established by the Commission Regulation (EC). Overall, the results from this study may contribute to improving the production process and quality control of coalho cheese.

Impact of animal origin of milk, processing technology, type of product, and price on the Boursin cheese choice process: Insights of a discrete choice experiment and eye tracking.

Boursin is a versatile semisoft cheese that can be made with different types of milk. While widely distributed in the European and North American markets, Boursin is produced to a limited extent in Brazil despite its commercial potential. This scenario encourages consumer-oriented product development studies by facilitating data collection with less bias and fewer product preconceptions, thus favoring the investigation of technological aspects of commercial interest. This study evaluates Brazilians' perceptions regarding different versions of Boursin cheese, with the aim of gaining a better understanding of the factors related to choosing cheese. Four attributes related to cheese production were evaluated at three different levels using two discrete choice experiments: one with eye tracking (n=20) and another without (n=312). These attributes included "type of processing" (evaluating pasteurization, ohmic heating, and preparation with raw milk), "animal origin of milk" (cow, goat, or buffalo milk), "type of product" (traditional, light, and lactose-free versions), and "price" (10.99, 13.99, and 16.99 BRL). Information regarding processing with ohmic heating did not affect the probability of Boursin being chosen, suggesting that consumers are open to using this emerging technology in Boursin cheese. However, information on being made with goat, buffalo, and raw milk negatively impacted the probability of choice, along with the price of 16.99 BRL. The frequency of cheese consumption and the level of health concerns also affected the probability of choosing the product. PRACTICAL APPLICATION: Identifying the relationship between extrinsic attributes presented on the Boursin cheese label and the consumer's choice process can aid the communication process with the target audience and reveal how some technological issues of interest to manufacturers are perceived. This study indicates how information regarding the animal origin of the milk (cow, goat, and buffalo), the type of processing (pasteurization, ohmic heating, and raw milk), the version of the product (traditional, light, and lactose-free), and the price affect the consumer choice process. The results provide insights that can be applied to product processing and designing labels.

Hybrid Cheeses—Supplementation of Cheese with Plant-Based Ingredients for a Tasty, Nutritious and Sustainable Food Transition

With increasing awareness of the impact of food on the climate, consumers are gradually changing their dietary habits towards a more plant-based diet. While acceptable products have been developed in meat analogues and non-fermented dairy products, alternative fermented dairy products such as yogurt and particularly ripened hard and semi-soft cheese products are not yet satisfactory. Since the cheese category has such a broad range of flavors and applications, it has proven complicated to find plant-based sources able to mimic them in terms of texture, meltability, ripening and flavor. Moreover, plant-based dairy alternatives do not provide the same nutritional supply. New technological approaches are needed to make cheese production more sustainable, which should be integrated in the already existing conventional cheese production to ensure a fast and cost-efficient transition. This can be tackled by incorporating plant-based components into the milk matrix, creating so-called “hybrid cheeses”. This review will discuss the challenges of both animal- and plant-based cheese products and highlight how the combination of both matrices can associate the best properties of these two worlds in a hybrid product, reviewing current knowledge and development on the matter. Emphasis will be drawn to the selection and pre-processing of raw materials. Furthermore, the key challenges of removing the off-flavors and creating a desirable cheese flavor through fermentation will be discussed.

Challenge Test for Assessing the Growth Potential of Listeria Monocytogenes in Greek Soft Cheese (Anthotyros)

Foodborne listeriosis is one of the most serious and severe foodborne diseases, with a high mortality rate worldwide. Listeria monocytogenes’ (Lm) ability to survive under a diversity of conditions makes it a threat for food safety. Soft and semisoft cheeses are common RTE foods that support survival and growth of Lm due to their high moisture content and favorable pH. The aim of the present study was to assess, after artificial inoculation, the growth potential (Δ) of Lm in vacuum packed RTE soft Greek Anthotyros cheese. Growth potential of Lm was determined according to the new version of “EURL Lm Technical Guidance Document on challenge tests and durability studies for assessing shelf life of ready-to-eat foods related to Lm”. The results of our study revealed that the growth potential of Lm was (Δ) = 4.93 log10 CFU/g, indicating that the specific soft cheese “anthotyros” is a “Ready to eat food able to support growth of Lm and classified in food safety category 1.2 in the (EC) Regulation 2073/2005”. That means that the food business operator (FBO) must comply with the criteria that define that the bacterium must not be detected in 25 g (n = 5, c = 0) at the time of leaving the production plant. Through this study, we try to highlight the need for FBO to conduct relevant research to ensure that the ready-to-eat products which they produce, during their shelf life, do not support the growth of Lm.

Quantitative risk assessment model to investigate the public health impact of varying Listeria monocytogenes allowable levels in different food commodities: A retrospective analysis

Invasive listeriosis is a potentially fatal foodborne disease that according to this study may affect up to 32.9 % of the US population considered as increased risk and including people with underlying conditions and co-morbidities. Listeria monocytogenes has been scrutinized in research and surveillance programs worldwide in Ready-to-Eat (RTE) food commodities (RTE salads, deli meats, soft/semi-soft cheese, seafood) and frozen vegetables in the last 30 years with an estimated overall prevalence of 1.4–9.9 % worldwide (WD) and 0.5–3.8 % in the United States (US). Current L. monocytogenes control efforts have led to a prevalence reduction in the last 5 years of 4.9–62.9 % (WD) and 12.4–92.7 % (US). A quantitative risk assessment model was developed, estimating the probability of infection in the US susceptible population to be 10–10,000× higher than general population and the total number of estimated cases in the US was 1044 and 2089 cases by using the FAO/WHO and Pouillot dose-response models. Most cases were attributed to deli meats (>90 % of cases) followed by RTE salads (3.9–4.5 %), soft and semi-soft cheese and RTE seafood (0.5–1.0 %) and frozen vegetables (0.2–0.3 %). Cases attributed to the increased risk population corresponded to 96.6–98.0 % of the total cases with the highly susceptible population responsible for 46.9–80.1 % of the cases. Removing product lots with a concentration higher than 1 CFU/g reduced the prevalence of contamination by 15.7–88.3 % and number of cases by 55.9–100 %. Introducing lot-by-lot testing and defining allowable quantitative regulatory limits for low-risk RTE commodities may reduce the public health impact of L. monocytogenes and improve the availability of enumeration data.

Quantitative assessment of furosine, furfurals, and advanced glycation end products in different types of commercially available cheeses

The aim of this study was to investigate the occurrence of Maillard reaction products of different types of commercially available cheeses. Cheeses are the commonly consumed dairy products characterized by their many different flavors, textures and aromas. Pasteurization, fermentation and ripening are the key steps of cheese manufacturing, which might lead to the formation of some harmful products. In this study, furosine, furfurals, two “representative” advanced glycation end products (AGEs) were analyzed by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) and liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). The content of furosine in cheeses were the highest, followed by AGEs, while levels of furfurals were relatively low. The contents of these Maillard reaction products in hard and semi-hard cheeses were significantly higher than those in soft and semi-soft cheeses. Finally, the correlation between proximate composition and Maillard reaction products was further analyzed. • The 32 cheeses are divided into two main categories based on their moisture content. • Furosine, furfurals, and advanced glycation end products in cheeses were quantitated. • Hard cheeses had higher contents of furfurals and advanced glycation end products. • Cheeses had the highest content of furosine and very low levels of furfurals. • Correlation analysis between proximate composition and furosine, furfurals, and AGEs.

The occurrence, growth, and biocontrol of Listeria monocytogenes in fresh and surface-ripened soft and semisoft cheeses.

Listeria monocytogenes continues to pose a food safety risk in ready-to-eat foods, including fresh and soft/semisoft cheeses. Despite L. monocytogenes being detected regularly along the cheese production continuum, variations in cheese style and intrinsic/extrinsic factors throughout the production process (e.g., pH, water activity, and temperature) affect the potential for L. monocytogenes survival and growth. As novel preservation strategies against the growth of L. monocytogenes in susceptible cheeses, researchers have investigated the use of various biocontrol strategies, including bacteriocins and bacteriocin-producing cultures, bacteriophages, and competition with native microbiota. Bacteriocins produced by lactic acid bacteria (LAB) are of particular interest to the dairy industry since they are often effective against Gram-positive organisms such as L. monocytogenes, and because many LAB are granted Generally Regarded as Safe (GRAS) status by global food safety authorities. Similarly, bacteriophages are also considered a safe form of biocontrol since they have high specificity for their target bacterium. Both bacteriocins and bacteriophages have shown success in reducing L. monocytogenes populations in cheeses in the short term, but regrowth of surviving cells can commonly occur in the finished cheeses. Competition with native microbiota, not mediated by bacteriocin production, has also shown potential to inhibit the growth of L. monocytogenes in cheeses, but the mechanisms are still unclear. Here, we have reviewed the current knowledge on the growth of L. monocytogenes in fresh and surface-ripened soft and semisoft cheeses, as well as the various methods used for biocontrol of this common foodborne pathogen.

Pseudomonas spp.: Are Food Grade Organic Acids Efficient against These Spoilage Microorganisms in Fresh Cheeses?

Psychrotolerant Pseudomonas spp. are among the most common spoilage agents in fresh, soft and semi-soft cheeses; therefore, hurdles inhibiting their growth are in strong demand by producers. This study aimed to establish Minimal Inhibiting Concentrations (MICs) of lactic and acetic acid towards P. fluorescens and to evaluate the efficacy of a cheese surface treatment with these two organic acids. MICs were determined in Brain Heart Infusion broth at 30 °C: the inhibition was achieved at a concentration of 49.96 mM and 44.40 mM of acetic and lactic acid, respectively. Two series of inhibition tests were performed on fresh “Primo sale” cheese, inoculated with P. brenneri MGM3, then dipped into different acid solutions (acetic acid: 49.96, 99.92 and 149.88 mM; lactic acid: 44.40, 88.80 and 133.20 mM) and stored at 6 °C. P. brenneri MGM3 were enumerated, including a control series. A significantly lower growth was revealed at the highest concentrations tested, both for acetic (p < 0.01) and lactic acid (p < 0.05) if compared to control samples. A conditioning of “Primo sale” surface with organic acid solutions could be a useful hurdle for Pseudomonas inhibition and shelf-life extension; it should be applied in combination with other mild interventions to fight spoilage and maintain the original product characteristics.

A novel application of Monascus purpureus in semi‐soft cheese making

Monascus spp. and its rice fermentation products have been used as food colorants and flavor enhancers, as well as for meat preservation and wine brewing in the Asia for centuries. A novel application of Monascus purpureus in semi-soft cheese making was introduced in this paper. The changes in the dynamics of the microbiota during cheese ripening were investigated in this study using high through-put methods. The most dominant bacterial genus was determined to be Lactococcus, and the dominant fungal genus was Monascus. Also, some other genera were detected in the red cheese samples, such as Leuconostoc. Samples of the Cheese were analyzed using dynamic oscillating rheology and the result indicated an elastic solid character rheological behavior. It was observed that the level of citrinin produced by Monascus and other fungal genera in the examined Cheese samples was lower than that produced in the red yeast rice. Furthermore, the mevinolin and γ- aminobutyric acid were also presence in Cheese samples. Therefore, the results of this study suggested that M. purpureus has positive effects on cheese making processes. Novelty impact statement A Novel Application of Monascus in Semi-Soft Cheese making has been introduced by our investigated team, which is referred to as Red Cheese. The processing of the Red Cheese has been researched and introduced in this paper. The nutrient content, texture, microbiota, and some other features were also tested in this paper.

Research of qualitative indicators of cacotta cheese

The amino acid composition of semi-soft Caciotta cheese, produced by Stella Alpina LLP was determined. Caciotta cheese, contains a large amount of protein and fat, and is a biologically valuable product. The energy value of cheese ranges from 10 to 18 kJ. 13 amino acids were found in the composition of Cacotta cheese. The research data shows that the largest in content of 7 out of 10 amino acids leucine, isoleucine, phenylalanine, valine, lysine, threonine, methionine are non-essential.

Determination of natamycin (food additive in cheese production) by liquid chromatography-electrospray tandem mass spectrometry

Natamycin is a polyene macrolide antifungal agent produced by aerobic fermentation of Streptomyces natalensis that prevents fungal growth on cheese surface. Commission Regulation EU 1129/2011 establishes a Union list of food additives and the use of natamycin (E235) in production of hard, semi-hard and semi-soft cheese, and lays down maximum residue limit (MRL) of 1mg/dm2 surface. It also stipulates that natamycin is not to be present at a depth of 5mm and deeper. The aim of this study was to present the analytical method for determination of natamycin in cheese by reverse phase liquid chromatography-electrospray tandem mass spectrometry. Method validation was performed according to Commission Decision 2002/657/EC. The method is linear in the concentration ranges of 0-5 mg/dm2, with the limit of detection (LoD) of 0.13 mg/dm2. The performance of the method was successfully verified by participating in a proficiency study.

Mycological and Mycotoxins Analysis of Kareish and Soft Cheese in Assiut, Egypt

During the present study 80 samples of kareish (semi-soft cheese with 20% fats) and soft cheese (40 % fats) were collected Assiut City during June to December 2015. The fungal content of these samples was evaluated using Dichloran Rose Bengal Chloramphenicol (DRBC) and Yeast Extract Malt extract (YM) agar media. The fungal count per sample ranged from 7 colonies/g in soft cheese to 44800 colonies/g in kareish cheese. the total number of fungal species in kareish cheese was slightly lower on DRBC than on YM (24 and 29 species respectively). The number of fungal species per sample fluctuated between 1-8 species with the highest being recovered from kareish cheese. Aspergillus was the most prevalent genus contaminating 45 -85 % of the samples with the highest being recovered from Kareish Cheese. Penicillium came next contaminating 20 - 47.5% of samples with white soft cheese being the most affected product. Candida, Clavispora, Klyveromyces and Pichia contaminated 2.5-65 % of samples and the highest incidence was that of Clavispora in kareish cheese. Aspergillus niger, A. fumigatus, A. flavus, Penicillium chrysogenum, P. aurantiogriseum and P. brevicompactum were the commonest species in cheese samples. Some yeast fungi were identified by sequencing of rRNA gene. Among the 19 species of yeasts Candida tropicalis, Clavispora lusitaniae, Pichia kudriavzevii, Pichia membranifaciens and kluyveromyces lactis were the most common. Testing the natural occurrence of aflatoxins revealed that AFM1 contaminated 55% and 50 % of kareish and soft cheese respectively whereas AFM2 was found only in 10 % of kareish cheese samples.

Survey for Listeria monocytogenes in and on Ready-to-Eat Foods from Retail Establishments in the United States (2010 through 2013): Assessing Potential Changes of Pathogen Prevalence and Levels in a Decade

A multiyear interagency Listeria monocytogenes Market Basket Survey was undertaken for selected refrigerated ready-to-eat foods purchased at retail in four FoodNet sites in the United States. Food samples from 16 food categories in six broad groups (seafood, produce, dairy, meat, eggs, and combination foods) were collected weekly at large national chain supermarkets and independent grocery stores in California, Maryland, Connecticut, and Georgia for 100 weeks between December 2010 and March 2013. Of the 27,389 total samples, 116 samples tested positive by the BAX PCR system for L. monocytogenes , and the pathogen was isolated and confirmed for 102 samples. Among the 16 food categories, the proportion of positive samples (i.e., without considering clustering effects) based on recovery of a viable isolate of L. monocytogenes ranged from 0.00% (95% confidence interval: 0.00, 0.18) for the category of soft-ripened and semisoft cheese to 1.07% (0.63, 1.68) for raw cut vegetables. Among the 571 samples that tested positive for Listeria-like organisms, the proportion of positive samples ranged from 0.79% (0.45, 1.28) for soft-ripened and semisoft cheese to 4.76% (2.80, 7.51) for fresh crab meat or sushi. Across all 16 categories, L. monocytogenes contamination was significantly associated with the four states (P < 0.05) but not with the packaging location (prepackaged by the manufacturer versus made and/or packaged in the store), the type of store (national chain versus independent), or the season. Among the 102 samples positive for L. monocytogenes , levels ranged from <0.036 most probable number per g to 6.1 log CFU/g. For delicatessen (deli) meats, smoked seafood, seafood salads, soft-ripened and semisoft cheeses, and deli-type salads without meat, the percentage of positive samples was significantly lower (P < 0.001) in this survey than that reported a decade ago based on comparable surveys in the United States. Use of mixed logistic regression models to address clustering effects with regard to the stores revealed that L. monocytogenes prevalence ranged from 0.11% (0.03, 0.34) for sprouts (prepackaged) to 1.01% (0.58, 1.74) for raw cut vegetables (prepackaged).

Multiple Vitamin K Forms Exist in Dairy Foods

BackgroundThe plant-based form of vitamin K (phylloquinone, vitamin K-1) has been well quantified in the US diet. Menaquinones (vitamin K-2) are another class of vitamin K compounds that differ from phylloquinone in the length and saturation of their side chain, but they have not been well characterized in foods. ObjectivesThe objectives of this study were to 1) quantify phylloquinone and the different forms of menaquinones [menaquinone (MK) 4–MK13] in milk, yogurt, Greek yogurt, creams, and cheeses and 2) compare the menaquinone contents of full-fat, reduced-fat, and nonfat dairy products. MethodsAll dairy samples were either obtained from the USDA National Food and Nutrient Analysis Program or purchased from retail outlets. Phylloquinone and menaquinone concentrations in these dairy products were quantified by mass spectrometry technology. ResultsFull-fat dairy products contained appreciable amounts of menaquinones, primarily in the forms of MK9, MK10, and MK11. We also measured modest amounts of phylloquinone, MK4, MK8, and MK12 in these products. In contrast, there was little MK5–7 or MK13 detected in the majority of dairy products. The total vitamin K contents of soft cheese, blue cheese, semi-soft cheese, and hard cheese were (means ± SEMs): 506 ± 63, 440 ± 41, 289 ± 38, and 282 ± 5.0 µg/100 g, respectively. Nonfermented cheeses, such as processed cheese, contained lower amounts of vitamin K (98 ± 11 µg/100 g). Reduced-fat or fat-free dairy products contained ∼5–22% of the vitamin K found in full-fat equivalents. For example, total vitamin K contents of full-fat milk (4% fat), 2%-fat milk, 1%-fat milk, and nonfat milk were 38.1 ± 8.6, 19.4 ± 7.7, 12.9 ± 2.0, and 7.7 ± 2.9 µg/100 g, respectively. ConclusionsTo the best of our knowledge, this is the first report of menaquinone contents of US dairy products. Findings indicate that the amount of vitamin K contents in dairy products is high and proportional to the fat content of the product.

Overview of Food Safety Hazards in the European Dairy Supply Chain.

Monitoring of dairy products should preferably focus on the most relevant food safety hazards in the dairy supply chain. For this purpose, the possible presence of microbiological, chemical, and physical hazards as well as trends in the dairy supply chain that may affect their presence were assessed. A literature review was combined with available data from EFSA, RASFF, and the Dutch monitoring program on chemical hazards as well as expert information. This study revealed that microbiological hazards are encountered more frequently in dairy products than chemical and physical hazards. Listeria monocytogenes, Staphylococcus aureus, Salmonella, and human pathogenic Escherichia coli were identified as the most important microbiological hazards in dairy products. Soft and semisoft cheeses are most frequently associated with L. monocytogenes and S. aureus enterotoxins, whereas raw milk is most frequently associated with human pathogenic E. coli and Campylobacter spp., Cronobacter spp., and Salmonella spp. are the microbiological hazards of most concern in powdered infant formula. Based on literature, monitoring, and RASFF data, the most relevant chemical hazards in dairy products are aflatoxin M1 , dioxins, and dioxin-like compounds and residues of veterinary drugs. Chemical hazards primarily occur at the dairy farm and may accumulate during further processing. The most relevant physical hazards are metal, glass, and plastic particles introduced during processing. Analysis of trends in the near future revealed that increased milk production is seen as most relevant in relation to food safety. Other trends affecting food safety are climate change and changes at the farm level, which aim to improve animal welfare and environmental sustainability.

Listeria monocytogenes cross-contamination of cheese: risk throughout the food supply chain.

Listeria monocytogenes has been the most common microbial cause of cheese-related recalls in both the United States and Canada in recent years. Since L. monocytogenes is inactivated by pasteurization, the majority of these cases have been linked to environmental and cross-contamination of fresh-soft, soft-ripened, and semi-soft cheeses. Cross-contamination of foods with L. monocytogenes is a continuous risk throughout the food supply chain and presents unique challenges for subsequent illness and outbreak investigations. Reports on outbreaks of listeriosis attributed to cross-contamination downstream from primary processing help highlight the critical role of epidemiological investigation coupled with coordinated molecular subtyping and surveillance in the recognition and investigation of complex foodborne outbreaks. Despite their complexity, environmental sampling throughout the supply chain coupled with improved genotyping approaches and concomitant analysis of foodborne illness epidemiological exposure data are needed to help resolve these and similar cases more rapidly and with greater confidence.

Uncoupling ‘growth’ and ‘increasing cell numbers’ of Listeria monocytogenes in naturally contaminated milk from a sub-clinically infected cow

Listeria monocytogenes is a virulent pathogen that is the causative agent of listeriosis, a rare and potentially fatal foodborne disease. The aim of this study was to assess the behaviour of L. monocytogenes in milk obtained from a cow with a sub-clinical infection, representing naturally contaminated milk. Within four hours of milking, the inhibitors Nisin V and pediocin from Pediococcus acidilactici, were added (at a concentration previously found to be inhibitory) to this naturally contaminated milk. The naturally contaminated milk was also pre-chilled at 4 °C for 24 h and then the inhibitors added. All the milk samples were incubated at 30 °C for 10 h. Samples were taken at hourly intervals for pH measurement and L. monocytogenes enumeration. The naturally contaminated milk was used to manufacture a laboratory-scale semi-soft cheese, in triplicate, using fresh and frozen starter cultures, and ripened at 15 °C for 3 weeks. Using an isolated strain from the naturally contaminated milk, growth in milk and during cheesemaking and ripening was also studied. Increasing numbers of L. monocytogenes were measured in the naturally contaminated milk, even in the presence of the bacteriocins. The chilled naturally contaminated milk had a higher initial number of L. monocytogenes than the freshly analysed milk. This implies that in the naturally contaminated milk used in this study, ‘increasing numbers’ of L. monocytogenes was uncoupled from ‘growth’; the increasing numbers may be due to breaking of clumps of cells in the naturally contaminated milk directly from the cow into individual cells, implying growth. Liquid starter culture of direct vat starter culture had little impact on the behaviour of L. monocytogenes during cheesemaking or ripening, the final numbers being the same in the ripened cheese as in the starting milk. The study contributes to risk assessment of naturally contaminated milk with respect to L. monocytogenes.

Risk Assessment of Human Listeriosis from Semisoft Cheeses Made from Raw Sheep's Milk in Lazio and Tuscany (Italy).

Semisoft cheese made from raw sheep's milk is traditionally and economically important in southern Europe. However, raw milk cheese is also a known vehicle of human listeriosis and contamination of sheep cheese with Listeria monocytogenes has been reported. In the present study, we have developed and applied a quantitative risk assessment model, based on available evidence and challenge testing, to estimate risk of invasive listeriosis due to consumption of an artisanal sheep cheese made with raw milk collected from a single flock in central Italy. In the model, contamination of milk may originate from the farm environment or from mastitic animals, with potential growth of the pathogen in bulk milk and during cheese ripening. Based on the 48-day challenge test of a local semisoft raw sheep's milk cheese we found limited growth only during the initial phase of ripening (24 hours) and no growth or limited decline during the following ripening period. In our simulation, in the baseline scenario, 2.2% of cheese servings are estimated to have at least 1 colony forming unit (CFU) per gram. Of these, 15.1% would be above the current E.U. limit of 100 CFU/g (5.2% would exceed 1,000 CFU/g). Risk of invasive listeriosis per random serving is estimated in the 10-12 range (mean) for healthy adults, and in the 10-10 range (mean) for vulnerable populations. When small flocks (10-36 animals) are combined with the presence of a sheep with undetected subclinical mastitis, risk of listeriosis increases and such flocks may represent a public health risk.

Listeria monocytogenes in ready-to-eat foods in Italy: Prevalence of contamination at retail and characterisation of strains from meat products and cheese

In the framework of a European Union (EU) Coordinated Monitoring Programme, different types of ready-to eat (RTE) products, including soft and semi-soft cheese (n = 398) and cooked meat products (n = 403), were collected at retail in Italy and tested for detection and enumeration of Listeria monocytogenes. An Integrative Survey of 2696 samples, including soft and semi-soft cheese (n = 894) and cooked meat products (n = 1802) was carried out to have statistically representative results at the national level. Considering the results obtained both from the EU and the national Integrative Survey, prevalence of contamination of meat products was 1.66% (95% CL: 1.02–2.73%) at the arrival of the samples at the laboratory and 1.92% (95% CL: 1.31%–2.82%) at the end of shelf-life. Spalla cotta was the most frequently contaminated meat product. Prevalence of contamination in cheese was 2.13% (95% CL: 1.37%–3.3%) at the arrival at the laboratory and 1.01% (95% CL: 0.41%–2.55%) at the end of shelf-life. To get information about differences between cheese rinds and pastes, these two parts were separately analysed in the Integrative Survey samples. L. monocytogenes was detected in 4.02% (95% CL: 2.60%–6.19%) of cheese rinds (n = 473), whereas only the 0.34% (95% CL: 0.12%–0.98%) of cheese pastes (n = 894) were contaminated. This difference was statistically significant (χ2 = 10.026, P < 0.05). Gorgonzola and Taleggio were the most frequently contaminated cheeses. Non-compliance with EU official criteria (100 CFU/g) was reported in 0.55% of meat products at arrival at the laboratory, in 0.46% at the end of shelf-life, and in 1.9% of cheese rinds. PFGE showed that cheese rinds could have been the origin of the few pastes' contamination, highlighting genetic similarity between isolates found in these two cheese components. Genetic subtyping also showed the presence of different pulsotypes, usually belonging to different clusters, in isolates from different food types. The presence of some pulsotypes predominantly prevalent over the others, in products from the same manufacturer, could suggest environmental strains as the main source of contamination.

Definition and usage of food safety margins for verifying compliance of Food Safety Objectives

Over the last decade, risk analysis has gradually been introduced as a tool to make decisions about food safety policies. In this framework, the ALOP (Appropriate Level of Protection) concept, which can be seen as a statement of the degree of public protection that should be attained in a country, was introduced. In addition, FSO (Food Safety Objectives) was introduced to provide a link between the ALOP and target points/goals in the supply chain. Historically, ALOP and FSO decisions have been based on the ALARA (As Low As reasonably Achievable) approach. Since an ALARA approach is based on the status of current technology, it is likely that the ALOP is attainable, provided a substantial portion of the industry complies with technological requirements or adopt “best practices” that will achieve the FSO. Food managers must control and government agencies must enforce and monitor the fulfilment of FSO. Once FSO has been established and adopted by the food industry, a major concern is to evaluate the results of the implementation of FSO in order to verify compliance. This paper introduces the concept of food safety margin (FSM) and its formulation based on classical and probabilistic approaches, which are intended to be used as a tool to measure the degree of compliance with FSO. For a better understanding of how food safety margins perform, FSM are estimated for Listeria monocytogenes in three different products, (semi-soft cheese, heat treated meat and cold smoked salmon). The results obtained, adopting both classical and probabilistic approaches, are discussed.