Category Archives: microbial contamination

Research – Prediction of Salmonella presence and absence in agricultural surface waters by artificial intelligence approaches

Wiley Online Salmonella kswfoodworld

The purpose of this study was to evaluate the performance of artificial intelligence tools for the prediction of Salmonella presence and absence in agricultural surface waters based on the population of microbiological indicators (total coliform, generic Escherichia coli, and enterococci) and physicochemical attributes of water (air and water temperature, conductivity, ORP, pH, and turbidity). Previously collected data set from six agricultural ponds monitored for two growing seasons were used for analysis. Classification algorithms including artificial neural networks (ANNs), the nearest neighborhood algorithm (kNN), and support vector machines (SVM) were trained and tested with a 539‐point data set for optimum prediction accuracy. Classification accuracy performances were validated with data set (400 samples) collected from different agricultural surface water sources. All tested algorithms yielded the highest accuracy around 75 ± 1% for generic E. coli followed by enterococci (65 ± 5%) and total coliform (60 ± 10%). Classifiers calculated 6–15% higher accuracy ranging from 62 to 66% for turbidity than all other tested physicochemical attributes. Based on E. coli populations measured in other water sources, trained algorithms predicted the presence and absence of Salmonella with an accuracy between 58.15 and 59.23%. The classification performance of ANN, kNN, and SVM algorithms are encouraging for the prediction of Salmonella in agricultural surface waters.

UK – Happy Hounds is recalling a range of its frozen raw dog food products because they may pose a risk to health

FSA

Happy Hounds is recalling a range of its frozen raw dog food products on a precautionary basis because they may pose a risk to human and animal health.

Risk statement

Happy Hounds is recalling a range of its frozen raw dog food products on a precautionary basis as they may pose a risk to human and animal health. Sampling undertaken by the company has identified elevated levels of bacteria indicating a potential risk. A withdrawal and recall have been actioned by the company.

Action taken by the company

Happy Hounds is recalling the above products on a precautionary basis

Our advice to consumers

Our advice consumers (pet owners):
If you have bought any of the above products do not use them. Instead, return them to the store from where they were bought for a full refund.

When handling and serving raw pet food it is always advised to clean utensils and
feeding bowls thoroughly after use. Consumers should wash hands thoroughly after handling raw pet food, bowls, utensils or after contact with the faeces of animals. Raw pet food should be stored separately from any food (especially ready to
eat foods). Care should be taken when defrosting to avoid cross contamination of foods and surfaces.

Research – A Successful Technique for the Surface Decontamination of Salmonella enterica Serovar Typhimurium Externally Contaminated Whole Shell Eggs Using Common Commercial Kitchen Equipment

Mary Ann Liebert hazegg.jpg

Eggs are a highly nutritious food source used in a wide range of food products. In Australia, eggs are a frequent source of foodborne salmonellosis outbreaks, associated with eggshell contamination with Salmonella enterica serovar Typhimurium (ST). Despite their potentially hazardous nature, raw eggs are often used and consumed in mayonnaise, mousse, ice cream and eggnog. The aim of this study was to develop a shell egg decontamination method that removed ST contamination from the outside of an egg without impacting its usability. The decontamination method was developed by the adaptation of a temperature-controlled water bath (commonly present in kitchens and associated with the sous-vide technique) for the surface decontamination of eggs. The outside of whole eggs was artificially inoculated with two ST strains. The eggs were decontaminated by placing in a sous-vide cooker with the water heated to 57°C. The remaining viable ST present on the whole shell egg, crushed shells, internal egg contents and sous-vide water were enumerated over time by culturing onto XLD agar. The quality of the uncontaminated heat-treated eggs was determined by measuring the Haugh unit, yolk index, albumen pH, thermocoagulation, and stability of foam. A blind control study was conducted to assess the acceptability and usability of the treated eggs by chefs and food handlers for the preparation of mayonnaise. Complete decontamination of ST was achieved by treating eggs for 9 min in the sous-vide cooker (57°C). No statistically significant difference was observed in the quality of treated eggs compared with nontreated eggs using the quality measurements and acceptability score from chefs. This method provides a simple approach that can be adopted by chefs and food handlers to obtain safe eggs before the preparation of raw egg products.

Research -The Complex Effect of Food Matrix Fat Content on Thermal Inactivation of Listeria monocytogenes: Case Study in Emulsion and Gelled Emulsion Model Systems

Frontiers in Microbiology

Previous studies on the influence of food matrix fat content on thermal inactivation kinetics of food pathogens have shown contradictory results due to the combined influence of fat content and other factors such as composition. Therefore, thermal inactivation of Listeria monocytogenes at 59, 64, and 69°C was systematically investigated in emulsion and gelled emulsion food model systems with various fat content (1, 5, 10, and 20%), such that the effect of fat content was isolated. Thermal conductivity and rheological properties of the model systems were quantified, as well as the effect of these properties on the thermal load of the model systems. Thermal conductivity was complexly related to fat content, the nature of the food matrix (i.e., viscous or gelled), and temperature. For the emulsions, the consistency index K increased with increasing fat content, while the flow behavior index n followed the opposite trend. For the gelled emulsions, the storage modulus G′ was always larger than the loss modulus G″ (i.e., measure of elastic and viscous properties, respectively). The phase angle δ [i.e., arctan (G″/G′)] was proportional with fat content, but this relation became more complex at higher temperatures. The thermal load of the model systems was not largely affected by food matrix fat content. Thermal inactivation of L. monocytogenes was investigated by means of the maximum specific inactivation rate kmax, log reductions, and sublethal injury (SI). Both for emulsions and gelled emulsions, kmax decreased with increasing fat content below approximately 60°C, while a more complex behavior was observed at higher temperatures. In the emulsions, log reductions were considerably lower (i.e., 2–3 log) at 1% fat than in systems with higher fat content. In the gelled emulsions, log reductions generally decreased with increasing fat content. SI decreased with increasing fat content, both in emulsions and gelled emulsions. In conclusion, the inactivation rate (i.e., kmax) of L. monocytogenes was affected by a complex relation between food matrix fat content, thermal conductivity, rheological properties, and inactivation temperature. Due to the small scale of the model systems, differences in kmax did not directly affect the final log reductions in a similar fashion.

Research – VA/starch/propolis/anthocyanins rosemary extract composite films as active and intelligent food packaging materials

Wiley Online

Active and intelligent food packaging films has taken more importance over conventional packaging. The aim of this study was to develop active and intelligent food packaging films based on bio‐degradable polymers like polyvinyl alcohol and starch, incorporated with natural additives, that is, propolis extract (PE) and Anthocyanin. Boric acid was used as a cross‐linker. The results proved the compatibility of films mixture. The mechanical strength was also measured and highest value was achieved 6.1 MPa for films containing 20% PE. Moreover, the maximum zone of inhabitation, that is, 21 and 15 mm, was also achieved at same composition against Escherichia coli and methicillin‐resistant Staphylococcus aureus, respectively. Furthermore, all films had shown great color response against different pH ranging from 2 to 14. Finally, food spoilage test was performed using pasteurized milk. Films responded visibly by changing color and protected milk from spoilage. Hence, formulated bio‐degradable active and intelligent films can be used as food packaging material.

Research – Effects of post‐packaging pasteurization process on microbial, chemical, and sensory qualities of ready‐to‐eat cured vacuum‐packed Turkey breast

Wiley Online

Ready‐to‐eat (RTE) cured vacuum‐packed turkey breast was pasteurized (80°C, 5.5 min) and stored at 8°C (like supermarkets refrigerator temperature). After 42 days (current shelf life of this product), in control group (RTE cured vacuum‐packed turkey breast), the number of mesophilic, anaerobic, lactic acid bacteria, mold and yeast, coliform, and psychrotrophic increased 5.82, 6.85, 5.85, 4.75, 1.49, and 5.57 log CFU/g, respectively. However, in the pasteurized samples, the number of mesophilic, anaerobic, and lactic acid bacteria increased 1.86, 2.12, and 2.28 log CFU/g, respectively, and mold and yeast, coliform, and psychrotrophic bacteria were under the detection limit. The effects of post‐packaging pasteurization on the reduction of total mesophilic, anaerobic and lactic acid bacteria counts on Day 42 of storage was 7.04 ± 0.33, 4.73 ± 0.11, and 5.58 ± 0.11 log CFU/g, respectively. Sensory quality of treated samples was significantly better than the control’s (p < .05). Post‐packaging pasteurization (PPP) significantly inhibited the reduction in the pH and the increase in TVB‐N, TBARS, titratable acidity, and drip loss (p < .05). This study shows the effectiveness of PPP on microbial, chemical, and sensory quality of cured vacuum‐packed turkey breast during cold storage.

RASFF Alerts – Animal Feed – Salmonella – Soybean Cake – Rapeseed Meal

RASFF-Logo

RASFF – Salmonella (present /25g) in soybean cake from Austria in Germany

RASFF – Salmonella (presence /25g) in soy bean cake from Austria in Austria

RASFF – Salmonella enterica ser. Havana (presence /25g) in rapeseed meal from Germany in Germany

Research – Predicting the antimicrobial effect of probiotic lactic acid bacteria against Staphylococcus aureus in white cheeses, using Fourier series modeling method

Wiley Online

MRSA Staphylococcus KSW Food World

Image CDC

In this study, it was aimed to design the time‐predicted inactivation model for various growth curves and the growth parameters representing the changes in the inactivation of Staphylococcus aureus in probiotic white cheese. For this purpose, S. aureus were inoculated in the pasteurized milk and the production of probiotic white cheese was performed in five different groups, and then samples were matured for 60 days at 4°C. S. aureus, Lactobacillus rhamnosus, Lactobacillus casei Shirota, and mesophilic starter culture levels of the samples were analyzed on the 1st, 4th, 7th, 10th, 15th, 30th, and 60th days of maturation. The inactivation model evaluation was performed by using the number of microorganisms counted with Fourier modeling method. In determining the model to be applied, the coefficient of determination (R2) and the sum of squared errors (SSE) for the mean number of microorganisms detected via modeling method were used. As conclusions, the number of S. aureus has decreased by approximately 5 logarithmic units at the end of the storage period by using probiotics together with the starter culture. It was determined that the Fourier modeling method is a suitable inactivation model with R2 values of 0.9847–0.9986 and SSE values of 0.094–0.510.

USA -Rompe Pecho Products Recalled For Microbial Contamination

Food Poisoning Bulletin

Efficient Laboratories is voluntarily recalling one lot each of Rompe Pecho EX, CF, and MAX liquid. These products are used to treat symptoms of the flu and the common cold. The three lots have been found to contain microbial contamination.

The recall notice did not state what type of microbe may have contaminated these products, but it did state that “In rare circumstances, consumption of Rompe Pecho from these lots could result in vomiting and diarrhea. Efficient Laboratories has not received any reports of adverse events to date.”

Research – Salmonella enterica Serovar Typhimurium 14028s Genomic Regions Required for Colonization of Lettuce Leaves

Frontiers in Microbiology

Contamination of edible produce leaves with human bacterial pathogens has been associated with serious disease outbreaks and has become a major public health concern affecting all aspects of the market, from farmers to consumers. While pathogen populations residing on the surface of ready-to-eat produce can be potentially removed through thorough washing, there is no disinfection technology available that effectively eliminates internal bacterial populations. By screening 303 multi-gene deletion (MGD) mutants of Salmonella enterica serovar Typhimurium (STm) 14028s, we were able to identify ten genomic regions that play a role in opening the stomatal pore of lettuce leaves. The major metabolic functions of the deleted regions are associated with sensing the environment, bacterium movement, transport through the bacterial membrane, and biosynthesis of surface appendages. Interestingly, at 21 days post inoculation, seven of these mutants showed increased population titers inside the leaf, two mutants showed similar titers as the wild type bacterium, whereas one mutant with a large deletion that includes the Salmonella pathogenicity island 2 (SPI-2) showed significantly impaired persistence in the leaf apoplast. These findings suggest that not all the genomic regions required for initiation of leaf colonization (i.e., epiphytic behavior and tissue penetration) are essential for continuing bacterial survival as an endophyte. We also observed that mutants lacking either SPI-1 (Mut3) or SPI-2 (Mut9) induce callose deposition levels comparable to those of the wild type STm 14028s; therefore, these islands do not seem to affect this lettuce defense mechanism. However, the growth of Mut9, but not Mut3, was significantly impaired in the leaf apoplastic wash fluid (AWF) suggesting that the STm persistence in the apoplast may be linked to nutrient acquisition capabilities or overall bacterial fitness in this niche, which are dependent on the gene(s) deleted in the Mut9 strain. The genetic basis of STm colonization of leaves investigated in this study provides a foundation from which to develop mitigation tactics to enhance food safety.