Evaluation of the food safety management system in a hospital food service operation toward Listeria monocytogenes

Integrated risk prioritization and action selection for cold chain

Cold chain, which affects human health and quality of life, is applied for temperature-sensitive and perishable products. Any problems occurring in the cold chain can cause deterioration in products, causing poisoning, death, or various diseases. There are many stages in the cold chain itself and the risk significance level of each stage is different. Therefore, the risks that occur depending on the weight of the stages in the cold chain should be defined and minimized and action plans are needed to be formed. Every action in the action plan cannot be implemented simultaneously since each action requires a different amount of budget and time resources of the companies are finite. Hence, the risks occurring in the cold chain should be minimized with the maximum use of limited company resources. In this study, an integrated mathematical model with analytical hierarchy method and failure mode and effect analysis is proposed that will maximize the weighted risk reduction amount by considering the budget and time constraints of the companies at the same time. The proposed approach has been applied in the 3PL service provider and the results are discussed. According to the results of the study where maximum benefit is aimed with the actions taken against the dangers, the maximum objective function value was obtained at the second and third levels of the workforce and budget values by evaluating the different situations with scenario analyses. In this solution, it is foreseen that by taking 5 actions, improvement will be made in 14 hazards.

The Impact of Food Quality Information Services on Food Supply Chain Pricing Decisions and Coordination Mechanisms Based on the O2O E-Commerce Mode

This paper considers the price conflict problem between the online channel of a food processing factory and the offline channel of the food retailers in food supply chains by analyzing the pricing decisions and coordination mechanisms between the food processing factory and food retailers under the influence of a food quality information service. First, the Stackelberg game method and the Bertrand game method are used to optimize the pricing decisions with the goal of maximizing the profits of the food processing factory and retailer. The analysis shows that the food quality information service level is positively correlated with the price of the factory’s own channel, and the influence of the food quality information service level on the price of the food processing factory’s or the food retailer’s own channel is stronger than its influence on the price of a competitor’s channel. Second, the food supply chain members’ pricing decisions are analyzed using the case analysis method by considering practical problems in the food supply chain. The results indicate that the food processing factory should use the Stackelberg game to make pricing decisions. However, it is optimal for the food retailer to make pricing decisions under the Bertrand game, and the total profit of the food supply chain is optimized under centralized decision making. Finally, we use both the quantitative discount mechanism and the Stackelberg game method to analyze the profits obtained by the food processing factory and retailer. The results indicate that the food processing factory should implement a quantitative discount mechanism when the quantity discount coefficient is greater than 0.4, and the retailer should implement a quantity discount mechanism when the quantity discount coefficient is in the range of 0.25 to 0.4.

Bacterial adhesion capacity on food service contact surfaces

The aim of this study was to analyse the adhesion of E. coli, P. aeruginosa and S. aureus on food contact materials, such as polyethylene terephthalate, silicone, aluminium, Teflon and glass. Surface roughness, streaming potential and contact angle were measured. Bacterial properties by contact angle and specific charge density were characterised. The bacterial adhesion analysis using staining method and scanning electron microscopy showed the lowest adhesion on smooth aluminium and hydrophobic Teflon for most of the bacteria. However, our study indicates that hydrophobic bacteria with high specific charge density attach to those surfaces more intensively. In food services, safety could be increased by selecting material with low adhesion to prevent cross contamination.

Genetic Characterization of Listeria monocytogenes Isolates from Industrial and Retail Ready-to-Eat Meat-Based Foods and Their Relationship with Clinical Strains from Human Listeriosis in Portugal

Listeria monocytogenes isolates (n = 81) recovered from ready-to-eat meat-based food products (RTEMP) collected in industrial processing plants and retail establishments were genetically characterized for comparison with those from human clinical cases of listeriosis (n = 49). The aim was to assess RTEMP as a possible food source for human infection. L. monocytogenes was detected in 12.5% of the RTEMP samples, and in some cases, counts were above the European food safety criteria. All isolates were assessed by multiplex PCR for serogroup determination and detection of virulence-associated genes inlA, inlB, inlC, inlJ, plcA, hlyA, actA, and iap. Serogroups IIb and IVb dominated in RTEMP and human isolates, and all were positive for the assessed virulence genes. Antibiotic susceptibility testing by the disk diffusion method revealed a low level of resistance among the isolates. Pulsed-field gel electrophoresis (PFGE) of L. monocytogenes isolates, using restriction enzymes ApaI and AscI, revealed genetic variability and differentiated the isolates in five clusters. Although some pulsed-field gel electrophoresis profiles of particular RTEMP and human isolates seemed to be highly related, exhibiting more than 90% similarity, which suggests a possible common source, in most cases the strains were not genetically or temporally matched. The close genetic relatedness of RTEMP and human listeriosis strains stressed the importance of preventive measure implementation throughout the food chain.

Hospital-acquired listeriosis linked to a persistently contaminated milkshake machine

One case of hospital-acquired listeriosis was linked to milkshakes produced in a commercial-grade shake freezer machine. This machine was found to be contaminated with a strain of Listeria monocytogenes epidemiologically and molecularly linked to a contaminated pasteurized, dairy-based ice cream product at the same hospital a year earlier, despite repeated cleaning and sanitizing. Healthcare facilities should be aware of the potential for prolonged Listeria contamination of food service equipment. In addition, healthcare providers should consider counselling persons who have an increased risk for Listeria infections regarding foods that have caused Listeria infections. The prevalence of persistent Listeria contamination of commercial-grade milkshake machines in healthcare facilities and the risk associated with serving dairy-based ice cream products to hospitalized patients at increased risk for invasive L. monocytogenes infections should be further evaluated.

Relationships among hygiene indicators in take-away foodservice establishments and the impact of climatic conditions

AIMS

This paper examined the relationships among hygiene indicators in take-away foodservice establishments and the impact of climatic conditions.

METHODS AND RESULTS

A total of 7545 samples were collected encompassing 2050 from food handlers' (HF) hands, 3991 from stainless steel food contact surfaces (FCS) and 1504 samples from plastic FCS. The study covered a period of 43 months. Hygiene-indicator bacteria (total plate count, Enterobacteriaceae Staphylococcus) were determined from the samples collected from 559 different take-away establishments. Climatic conditions were evaluated in respect to the outside temperature, pressure, humidity and precipitation. Logistic regression confirmed that the presence of precipitation was associated with an increased likelihood of exhibiting both Enterobacteriaceae and Staphylococcus on HF' hands as well as exhibiting Enterobacteriaceae on both types of FCS. Numerable Enterobacteriaceae and Staphylococcus levels on HF' hands were detected when higher outside temperatures and higher precipitations occurred. Higher outside temperatures were observed when Enterobacteriaceae were detected on both plastics (P < 0·05) and stainless steel (P > 0·05). Higher precipitation was observed when Enterobacteriaceae was detected on stainless steel while in contrast, this indicator was detected on plastics in periods with lower precipitation.

CONCLUSIONS

This research confirms relationships between hygiene indicators in take-aways and climatic conditions, mostly temperature and precipitation.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides another perspective into the possible nature of cross-contamination and foodborne outbreaks originating in foodservice establishments and brings to attention the necessity of analysing various climatic conditions.