Impact of Cooking Procedures and Storage Practices at Home on Consumer Exposure to Listeria Monocytogenes and Salmonella Due to the Consumption of Pork Meat

[EN] The objective of this research was to analyze the impact of different cooking procedures (i.e., gas hob and traditional static oven) and levels of cooking (i.e., rare, medium, and well-done) on inactivation of Listeria monocytogenes and Salmonella in pork loin chops. Moreover, the consumer's exposure to both microorganisms after simulation of meat leftover storage at home was assessed. The results showed that well-done cooking in a static oven was the only treatment able to inactivate the tested pathogens. The other cooking combinations allowed to reach in the product temperatures always 73.6 degrees C, decreasing both pathogens between 6 log(10) cfu/g and 7 log(10) cfu/g. However, according to simulation results, the few cells surviving cooking treatments can multiply during storage by consumers up to 1 log(10) cfu/g, with probabilities of 0.059 (gas hob) and 0.035 (static oven) for L. monocytogenes and 0.049 (gas hob) and 0.031 (static oven) for Salmonella. The key factors affecting consumer exposure in relation to storage practices were probability of pathogen occurrence after cooking, doneness degree, time of storage, and time of storage at room temperature. The results of this study can be combined with prevalence data and dose-response models in risk assessment models and included in guidelines for consumers on practices to be followed to manage cooking of pork meat at home.The research leading to these results received funding from the E.U. Seventh Framework Programme under grant agreement KBBE 222738BASELINE (Selection and Improving of Fit-for-Purpose Sampling Procedures for Specific Foods and Risks).De Cesare, A.; Doménech Antich, EM.; Comin, D.; Meluzzi, A.; Manfreda, G. (2017). Impact of Cooking Procedures and Storage Practices at Home on Consumer Exposure to Listeria Monocytogenes and Salmonella Due to the Consumption of Pork Meat. Risk Analysis. 38(4):638-652. https://doi.org/10.1111/risa.12882S63865238

Quantitative risk assessment of human salmonellosis and listeriosis related to the consumption of raw milk in Italy.

Two quantitative risk assessment (RA) models were developed to describe the risk of salmonellosis and listeriosis linked to consumption of raw milk sold in vending machines in Italy. Exposure assessment considered the official microbiological records monitoring raw milk samples from vending machines performed by the regional veterinary authorities from 2008 to 2011, microbial growth during storage, destruction experiments, consumption frequency of raw milk, serving size, and consumption preference. Two separate RA models were developed: one for the consumption of boiled milk and the other for the consumption of raw milk. The RA models predicted no human listeriosis cases per year either in the best or worst storage conditions and with or without boiling raw milk, whereas the annual estimated cases of salmonellosis depend on the dose-response relationships used in the model, the milk storage conditions, and consumer behavior in relation to boiling raw milk or not. For example, the estimated salmonellosis cases ranged from no expected cases, assuming that the entire population boiled milk before consumption, to a maximum of 980,128 cases, assuming that the entire population drank raw milk without boiling, in the worst milk storage conditions, and with the lowest dose-response model. The findings of this study clearly show how consumer behavior could affect the probability and number of salmonellosis cases and in general, the risk of illness. Hence, the proposed RA models emphasize yet again that boiling milk before drinking is a simple yet effective tool to protect consumers against the risk of illness inherent in the consumption of raw milk. The models may also offer risk managers a useful tool to identify or implement appropriate measures to control the risk of acquiring foodborne pathogens. Quantification of the risks associated with raw milk consumption is necessary from a public health perspective

Four-Year Monitoring of Foodborne Pathogens in Raw Milk Sold by Vending Machines in Italy

Prevalence data were collected from official microbiological records monitoring four selected foodborne pathogens (Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni) in raw milk sold by self-service vending machines in seven Italian Regions (n. 60907 samples from 1239 vending machines) during the years 2008 to 2011. Data of samples analyzed both by culture-based and real-time PCR methods were collected in one Region. A total of 100 raw milk consumers in four regions were interviewed while purchasing raw milk from vending machines. One hundred and seventy eight samples out of 60907 were positive for one of the four foodborne pathogens investigated; overall, 18 samples were positive for Salmonella spp., 83 for L. monocytogenes, 24 for E. coli O157:H7 and 53 for C. jejuni in the seven Regions investigated. There were no significant differences in prevalence among Regions, but a significant increase in C. jejuni prevalence was observed over the years. A comparison of the two different analysis methods showed that real-time PCR is from 2.71 to 9.40 times more sensitive than culture-based method. Data on consumer habits showed that some behaviors may enhance the risk of infection due to raw milk consumption: 37% of consumers do not boil milk before consumption, 93% never use an insulated bag to transport raw milk home, and raw milk is consumed by children under five years of age. The study emphasizes that end-product controls alone are not sufficient to guarantee an adequate level of consumer protection. The beta distribution of positive samples in this study and the data on raw milk consumer habits are useful and appropriate for the development of a National Quantitative Risk Assessment of Salmonella spp., L. monocytogenes, E. coli O157 and C. jejuni related to raw milk consumption

Listeria monocytogenes Circulating in Rabbit Meat Products and Slaughterhouses in Italy: Prevalence Data and Comparison among Typing Results

Rabbit meat has outstanding dietetic and nutritional properties. However, few data on microbiological hazards associated with rabbit productions are available. In this study, the presence of Listeria monocytogenes was determined in 430 rabbit carcasses, 256 rabbit meat cuts and products, and 599 environmental sponges collected from four Italian rabbit slaughterhouses over a period of 1 year. Prevalence of L. monocytogenes among the 1285 rabbit meat and environmental samples was 11%, with statistically significant differences between slaughterhouses. The highest prevalence (33.6%) was observed in rabbit meat cuts and products; the majority of positive environmental samples were collected from conveyor belts. Overall, 27.9% and 14.3% of rabbit cuts and carcasses, respectively, had L. monocytogenes counts higher than 1 colony-forming unit (CFU)/10 g. A selection of 123 isolates from positive samples was genotyped and serotyped to determine genetic profiles and diversity among L. monocytogenes isolates contaminating different slaughterhouses and classes of products investigated. Discriminatory power and concordance among the results obtained using multilocus variable-number tandem-repeat analysis (MLVA), multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), automated EcoRI ribotyping, and serotyping were assessed. The isolates selected for typing were classified into serotypes 1/2a (52.8%), 1/2c (32.5%), and 1/2b (14.6%). The majority of the isolates were classified as ST14 (34.1%), ST9 (35.5%), ST121 (17.9%), and ST224 (14.6%). The greatest discriminatory power was observed with the MLVA typing, followed by MLST, PFGE, and ribotyping. The best bidirectional concordance was achieved between PFGE and MLST. There was 100% correlation between both MLST and MLVA with serotype. Moreover, a high unidirectional correspondence was observed between MLVA and both MLST and PFGE, as well as between PFGE and both MLST and serotyping. The results of this study show for the first time in Italy prevalence and genetic profiles of L. monocytogenes isolated in rabbit products and slaughterhouses

Effectiveness of washing procedures in reducing Salmonella enterica and Listeria monocytogenes on a raw leafy green vegetable (Eruca vesicaria)

Vegetables are an important source of nutrients, but they can host a large microbial population, particularly bacteria. Vegetables are an important source of nutrients, but they can host a large microbial population, particularly bacteria. Foodborne pathogens can contaminate raw vegetables at any stage of their production process with a potential for human infection. Appropriate washing can mitigate the risk of foodborne illness consequent to vegetable consumption by reducing pathogen levels, but few data are available to assess the efficacy of different practices. In the present work, six different washing methods, in the presence or absence of sanitisers (peracetic acid and percitric acid, sodium bicarbonate, sodium hypochlorite) and vinegar, were tested for their effectiveness in reducing Salmonella and Listeria counts after artificial contamination of raw rocket (Eruca vescicaria). Results showed that washing with sodium hypochlorite (200 mg/L) was the only method able to produce a significant 2 Log reduction of Salmonella counts, but only in the case of high initial contamination (7 Log CFU/g), suggesting potential harmful effects for consumers could occur. In the case of Listeria monocytogenes, all the examined washing methods were effective, with 200 mg/L sodium hypochlorite solution and a solution of peracetic and percitric acids displaying the best performances (2 and 1.5 Log reductions, respectively). This highlights the importance of targeting consumers on fit for purpose and safe washing practices to circumvent vegetable contamination by foodborne pathogens

Human campylobacteriosis related to the consumption of raw milk sold by vending machines in Italy: quantitative risk assessment based on official controls over four years

open18noA quantitative risk assessment (RA) model was developed to describe the risk of campylobacteriosis linked to consumption of raw milk sold in vending machines in Italy. Exposure assessment was based on the official microbiological records of raw milk samples from vending machines monitored by the regional Veterinary Authorities from 2008 to 2011, microbial growth during storage, destruction experiments, consumption frequency of raw milk, serving size, consumption preference and age of consumers. The differential risk considered milk handled under regulation conditions (4°C throughout all phases) and the worst time-temperature field handling conditions detected. Two separate RA models were developed, one for the consumption of boiled milk and the other for the consumption of raw milk, and two different dose-response (D-R) relationships were considered. The RA model predicted no human campylobacteriosis cases per year either in the best (4°C) storage conditions or in the case of thermal abuse in case of boiling raw milk, whereas in case of raw milk consumption the annual estimated campylobacteriosis cases depend on the dose-response relationships used in the model (D-R I or D-R II), the milk time-temperature storage conditions, consumer behaviour and age of consumers, namely young (with two cut-off values of ≤5 or ≤6 years old for the sensitive population) versus adult consumers. The annual estimated cases for young consumers using D-R II for the sensitive population (≤5 years old) ranged between 1013.7/100,000 population and 8110.3/100,000 population and for adult consumers using D-R I between 79.4/100,000 population and 333.1/100,000 population. Quantification of the risks associated with raw milk consumption is necessary from a public health perspective and the proposed RA model represents a useful and flexible tool to perform future RAs based on local consumer habits to support decision-making on safety policies. Further educational programmes for raw milk consumers or potential raw milk consumers are required to encourage consumers to boil milk to reduce the associated risk of illness.openFederica Giacometti; Paolo Bonilauri; Simonetta Amatiste; Norma Arrigoni; Manila Bianchi; Marina Nadia Losio; Stefano Bilei; Giuseppe Cascone; Damiano Comin; Paolo Daminelli; Lucia Decastelli; Giuseppe Merialdi; Renzo Mioni; Angelo Peli; Annalisa Petruzzelli; Franco Tonucci; Silvia Piva; Andrea Serraino.Federica Giacometti; Paolo Bonilauri; Simonetta Amatiste; Norma Arrigoni; Manila Bianchi; Marina Nadia Losio; Stefano Bilei; Giuseppe Cascone; Damiano Comin; Paolo Daminelli; Lucia Decastelli; Giuseppe Merialdi; Renzo Mioni; Angelo Peli; Annalisa Petruzzelli; Franco Tonucci; Silvia Piva; Andrea Serraino

Microbiological criteria for Campylobacter in broiler carcasses in Italy: A possible approach to derive them

The aim of this paper was to provide suitable microbiological criteria (MC) for Campylobacter in broiler carcasses and a sampling plan to verify compliance with such criteria. Data were gathered in the presence and concentration of Campylobacter in broiler carcasses collected in three different Italian slaughterhouses, labelled as A, B and C. The sampling plan to be validated in each slaughterhouse included the analysis of three different carcasses collected immediately after chilling from 30 different lots, for a total of 90 samples per slaughterhouse. The number of positive samples containing above 100 CFU/g and above 1000 CFU/g throughout the 30 tested lots was determined to estimate between-lot variability. Based on this information, the performance of four MC was evaluated for lot compliance: i) n = 3; c = 0; m = 100 CFU/g; ii) n = 3; c = 0; m = 1000 CFU/g; iii) n = 3; c = 1; m = 1000 CFU/g and iv) n = 3; c = 2; m = 1000 CFU/g. Positive Campylobacter samples were found in 60% of the lots tested in slaughterhouses A and C and in 73.3% of lots from slaughterhouse B. The differences among the three slaughterhouses in the mean Campylobacter levels found in positive samples were not significant and were used to evaluate the performance of the MC. The level of lot compliance to different MC was calculated and for the most stringent one (n = 3; c = 0; m = 100 CFU/g) was 40% at slaughterhouses A and C but only 26.7% at slaughterhouse B. The results of this study show an alternative approach to establish MC for Campylobacter in broilers. According to (1) Campylobacter prevalence and concentration in Italy, (2) applied experimental plan and (3) selected slaughterhouses, the number of compliant lots to the suggested MC ranged between 26.7 and 100%. The selection of the fit for purpose MC is a risk manager decision, based on a reasonable balance between public health and cost for poultry industries