Category Archives: Technology

Research – Microbial Safety and Sensory Analyses of Cold-Smoked Salmon Produced with Sodium-Reduced Mineral Salts and Organic Acid Salts

MDPI

Cold-smoked (CS) salmon contains high levels of sodium salts, and excess dietary sodium intake is associated with an array of health complications. CS salmon may also represent a food safety risk due to possible presence and growth of the foodborne pathogen Listeria monocytogenes which may cause fatal human infections. Here we determine how reformulated CS salmon using commercial sodium-reduced salt replacers containing KCl (e.g., Nutek, Smart Salt, SOLO-LITE) and acetate-based preservative salts (Provian K, proviant NDV) affect sensory properties, quality, and microbial safety. Initial sensory screening of sodium-reduced CS salmon was followed by L. monocytogenes growth analyses in selected variants of reformulated CS salmon, and finally by analyses of CS salmon variants produced in an industrial smokehouse. Projective mapping indicated overall minor sensory changes in sodium-replaced samples compared with a conventional product with NaCl. Growth of L. monocytogenes was temperature-dependent (4 °C vs. 8 °C storage) with similar growth in sodium-reduced and conventional CS salmon. The addition of 0.9% of the preservative salts Provian K or Provian NDV gave up to 4 log lower L. monocytogenes counts in both sodium-reduced and conventional cold-smoked salmon after 29 days of chilled storage. No changes in pH (range 6.20–6.33), aw levels (range 0.960–0.973), or weight yield (96.8 ± 0.2%) were evident in CS salmon with salt replacers or Provian preservative salts. Analyses of CS salmon produced with selected mineral salt and preservative salt combinations in an industrial salmon smokery indicated marginal differences in sensory properties. Samples with the preservative salt Provian NDV provided L. monocytogenes growth inhibition and low-level total viable counts (<2.8 log/g) dominated by Photobacterium and Carnobacterium during storage. Production of sodium-reduced CS salmon with inhibiting salts provides a simple method to achieve a healthier food product with increased food safety.

Research – Removal of Ochratoxin A from Grape Juice by Clarification: A Response Surface Methodology Study

MDPI

This study achieved maximum removal of ochratoxin A (OTA) during the grape juice clarification process with minimal reduction in antioxidant compounds (phenolic acid, flavonoids, and antioxidant capacity by FRAP) by the RSM method. Independent variables included three types of clarifiers—gelatin, bentonite, and diatomite (diatomaceous earth)—at a concentration level of 0.25–0.75% and clarification time of 1–3 h. OTA was measured by high-performance liquid chromatography with fluorescence detection. Clarifying agent concentration and clarification time affected the reduction amount of OTA and antioxidant compounds in grape juice. There was a direct linear correlation between the reduction amounts of OTA and antioxidant compounds and capacity with the concentration of bentonite, gelatin, and diatomite, and the clarification time. The reduction amount of OTA and antioxidant capacity followed the linear mode. However, the decreased phenolic acid and flavonoid values followed the quadratic model. The study results showed that if the concentrations of bentonite, gelatin, and diatomite and clarification time were 0.45, 0.62, 0.25%, and 1 h, respectively, the maximum amount of OTA reduction (41.67%) occurred. Furthermore, the phenolic acid, flavonoid, and antioxidant activity decrease amounts were at their lowest levels, i.e., 23.86, 7.20, and 17.27%, respectively. View Full-Text

Research – Inactivation of Foodborne Pathogens on Inshell Walnuts by UV-C Radiation

Journal of Food Protection

Inshell walnuts could be contaminated with pathogens through direct contact or cross-contamination during harvesting and postharvest hulling, drying, or storage. This study aimed to assess the efficacy of ultraviolet–C (UV–C) radiation in inactivating foodborne pathogens on inshell walnut surfaces. Intact inshell walnut surfaces were inoculated separately with Salmonella spp., Escherichia coli O157:H7, Listeria monocytogenes , and Staphylococcus aureus , and then subjected to UV–C radiation at doses of 29.4, 147.0, 294.0, 588.0, and 882.0 mJ/cm 2 . UV–C radiation inactivated the inoculated pathogens in a dose-dependent manner, and a tailing effect was observed for the inactivation of pathogens. UV–C radiation at 29.4 mJ/cm 2 and 882.0 mJ/cm 2 reduced the populations of  S . Enteritidis PT 30, S . Typhimurium, E. coli O157:H7, L. monocytogenes , and S. aureus on inshell walnut surfaces by 0.82–1.25 and 1.76–2.41 log CFU/walnut, respectively. Scanning electron photomicrographs showed pathogenic bacterial cells in the cracks and crevices of the inshell walnut surface, and the shielding of microorganisms by the cracks and crevices may have contributed to the tailing effect observed during UV–C inactivation. No significant changes ( p  > 0.05) were found in walnut lipid oxidation following UV–C radiation at doses up to 882.0 mJ/cm 2 . Together, the results indicate that UV–C radiation could be a potential technology for reducing the populations of various foodborne pathogens on inshell walnut surfaces while maintaining the quality of walnuts.

Research – Attachment and survival of Salmonella enterica and Listeria monocytogenes on tomatoes (Solanum lycopersicum) as affected by relative humidity, temperature and time of storage 

Journal of Food Protection

Tomatoes (Solanum lycopersicum) are one of the most consumed fruits worldwide. The fruit can become contaminated with Salmonella and Listeria monocytogenes at different stages of the production and supply chain, and these pathogens may survive under different storage conditions. The effect of relative humidity, temperature and time of storage on the attachment and survival characteristics of both pathogens on the surface of tomatoes was investigated. Fresh whole Roma tomatoes were inoculated with a cocktail of Salmonella or L. monocytogenes and stored at 5, 12, 25, 30, or 35 ºC for 10 days. Every day during storage, relative humidity and temperature were measured and tomatoes were removed to enumerate cells of these pathogens that were loosely attached (LA, cells detached from the tomato surface by simple rinse) and strongly attached (SA, cells that required sonication to detach. Enumeration was achieved by spread-plate method. Surviving populations of LA and SA cells were obtained and the attachment strength (SR) was calculated to express the proportion of SA cells on the tomato surface. The LA initial counts of Salmonella and L. monocytogenes on the surface of the fruit after inoculation were 6.6 and 6.5 log CFU/tomato, and for SA were 5.1 and 5.6 log CFU/tomato, respectively. For both pathogens, the LA counts were higher (p < 0.05) than the SA counts. Also, the LA and SA counts varied significantly as a function of temperature, relative humidity and time of storage. The S R for Salmonella was affected by the time but not the temperature of storage, while the S R for L. monocytogenes was affected by the temperature, relative humidity and time of storage (p < 0.05). Understanding the attachment and survival of Salmonella and L. monocytogenes on tomatoes stored at different temperature conditions may be useful in determining ways to prevent/reduce the establishment of pathogens and designing improved decontamination methods for tomatoes.

Research – The effectiveness and safety of high pressure food treatment

asca

Definition and applicable regulations

Type of food treated and processing conditions

Intrinsic and extrinsic factors of food that influence the effectiveness of high pressure treatment

Possible chemical and microbiological hazards associated with high pressure treatment

High pressure treatment as an alternative to pasteurization of milk

Efficacy of high pressure treatment for the control of Listeria monocytogenes in ready-to-eat foods

Research – Possible explanation for limited reduction of pathogens on radish microgreens after spray application of chlorinated water during growth with disperse contamination spread of abiotic surrogate on leaves

Wiley Online

The purpose of this study was to determine the efficacy of spray application of chlorinated water before harvest on the population of Salmonella enterica Typhimurium and Escherichia coli O157:H7 on radish microgreens. The transfer of abiotic surrogate to radish microgreens was also evaluated to track possible pathogen contamination spread by inoculating seed and growth media. During growth, microgreens inoculated with strains of pathogens were sprayed with chlorinated water at three different concentrations (0.50, 1.00, and 2.00 ± 0.05 ppm free chlorine). Spray application of chlorinated water was performed on microgreens once (day 9), twice (day 8 and 9), three (day 7, 8, and 9), and four times (day 6, 7, 8, and 9). Microgreens were harvested 12 hr after the last application of chlorinated water. Salmonella and E. coli O157:H7 populations were reduced with the increase in chlorine concentration. Chlorinated water reduced Salmonella and E. coli O157:H7 populations up to 1.1 log CFU/g (p < .05) and 0.9 log CFU/g (p > .05), respectively. Images taken under UV illumination provided the visualization of abiotic surrogate spread on cotyledon and upper hypocotyl (all edible parts) of radish microgreen plants regardless of seed or growth media inoculation. Scanning Electron Microscopy showed the presence of abiotic surrogate and generic E. coli on microgreen leaves. Spray application of chlorinated water during microgreen growth may help to reduce microbial load but cannot be used as the only control measure.

Research – Researchers study use of blue light technology for foodborne outbreaks

National Hog Farmer

Researchers from the University of Georgia Center for Food Safety are beginning a new study to investigate the effectiveness of antimicrobial blue light technology to reduce the foodborne pathogens that cause food poisoning.

When used as a means of disinfecting surfaces in a hospital setting, antimicrobial blue light technology has shown promising results, but little research has yet been done to explore its potential efficacy to control foodborne pathogens.

Through a three-year, $599,900 grant awarded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, UGA College of Agricultural and Environmental Sciences researchers will test the technology to uncover possible applications in the food production process.

Despite industry efforts, the number of foodborne infections has remained steady and, in some cases, has increased in recent years according to the Centers for Disease Control and Prevention (CDC).

Large-scale outbreaks and recalls still occur, particularly due to environmental contamination — like food preparation and processing surfaces — with Salmonella enterica and Listeria monocytogenes, both of which can cause illness and even death.

Most food manufacturers use chemical sanitizers on food preparation surfaces to help control the spread of foodborne pathogens.

This is typically effective in easy-to-reach areas, but areas that are hard to reach may not receive the same degree of sanitation.

These hard-to-reach places sometimes harbor biofilms, which are clusters of microorganisms such as bacteria that are hard to eliminate. The inadvertent spread of these microorganisms can occur during food production both by humans and machinery. Viruses pose a further challenge as many, such as norovirus, can survive on a variety of surfaces for long periods of time.

Research – Unraveling the Antimicrobial Effectiveness of Coridothymus capitatus Hydrolate against Listeria monocytogenes in Environmental Conditions Encountered in Foods: An In Vitro Study

MDPI

The increased resistance of bacteria to antimicrobials, as well as the growing interest in innovative and sustainable alternatives to traditional food additives, are driving research towards the use of natural food preservatives. Among these, hydrolates (HYs) have gained attention as “mild” alternatives to conventional antimicrobial compounds. In this study, the response of L. monocytogenes ATCC 7644 exposed to increasing concentrations of Coridothymus capitatus HY (CHY) for 1 h at 37 °C was evaluated by means of Phenotype Microarray, modelling the kinetic data obtained by inoculating control and treated cells into GEN III microplates, after CHY removal. The results revealed differences concerning the growth dynamics in environmental conditions commonly encountered in food processing environments (different carbon sources, pH 6.0, pH 5.0, 1–8% NaCl). More specifically, for treated cells, the lag phase was extended, the growth rate was slowed down and, in most cases, the maximum concentration was diminished, suggesting the persistence of stress even after CHY removal. Confocal Laser Scanner Microscopy evidenced a diffuse aggregation and suffering of the treated cells, as a response to the stress encountered. In conclusion, the treatment with HY caused a stressing effect that persisted after its removal. The results suggest the potential of CHY application to control L. monocytogenes in food environments.

Research – Preservation of cut fruit and use of a technological adjuvant for washing certain vegetables

ACSA

The Spanish Agency for Food Safety and Nutrition has published two new reports from its Scientific Committee:

  • Report on the storage conditions of fruit cut in half in retail establishments.
  • Report on the safety of the use of an aqueous solution of sodium lauryl ether sulfate as a processing aid for washing apples, peaches, bananas, tomatoes, peppers and citrus in processing plants .      

Report on the storage conditions of fruit cut in half in retail establishments

The AESAN Scientific Committee has assessed whether it is possible to keep melon, watermelon, pineapple and papaya cut in half at room temperature in retail establishments for a limited time, ensuring consumer safety.

The Scientific Committee has concluded that, on the basis of the information

  • Storage at room temperature of melon, watermelon, papaya and pineapple cut in half can pose a health risk as the physicochemical conditions (pH, water activity, total soluble solids, nutrient availability, etc.) are compatible with growth. of foodborne pathogens, such as Salmonella , E. coli verotoxigenic or L. monocytogenes .
  • In order to make the storage conditions of melon, watermelon, papaya and pineapple cut in half more flexible, temperatures below 25 ºC for a time of less than 3 may be allowed, as they do not pose a significant microbiological risk. hours in a place sufficiently ventilated and preserved from sunlight, followed by continuous refrigerated storage at temperatures below 5 ºC.
  • To minimize the health risk that these practices may pose, it is recommended to discard for cutting fruits with an excessive degree of ripeness, or that have wounds or cracks on their surface, as they can be a source of contamination.

Report on the safety of the use of an aqueous solution of sodium lauryl ether sulfate as a processing aid for washing apples, peaches, bananas, tomatoes, peppers and citrus in processing plants

The AESAN Scientific Committee has evaluated the safety of using an aqueous solution of sodium lauryl ether sulfate (27%) as a technological aid for washing apples, peaches, bananas, tomatoes, peppers and citrus in processing plants. request of a company request.

Sodium lauryl ether sulfate (LESS) is not authorized for human consumption.

As the presence of residues in the final products (fruits and vegetables) after the use of this aqueous solution cannot be ruled out, the technology adjuvant is classified as an unauthorized substance in human food whose Admissible Daily Intake (ADI) is not established and whose use may lead to the presence of technically unavoidable waste.

The Scientific Committee concludes that, based on the information provided by the applicant and taking into account the proposed composition and conditions of use, the use of the technology adjuvant does not imply a risk to the health of the consumer.

The conclusions of this report refer exclusively to the solution under evaluation as a technological aid in the proposed conditions of use and its composition, and may not be extended to formulations or conditions other than those evaluated, including joint use with other substances.

This evaluation does not imply an authorization for use or affect uses other than use as a technological aid in the process of washing apples, peaches, bananas, tomatoes, peppers and citrus in the processing plants. This use involves a final rinsing with drinking water, following the application of the washing water with the technological adjuvant, so that the possible residues in the fruits and vegetables are eliminated.

Click to access FRUTAS_CORTADAS.pdf

Click to access COADYUVANTE_LAURIL_ETER.PDF

Research – Evaluation of Hygiene Indicators and Sampling Plan for Detecting Microbial Contamination in Health Functional Foods

Journal of Food Protection

This study aimed to monitor microbial contamination level in a variety of health functional foods and to establish new microbial criteria. Indicator organisms (i.e., aerobic bacteria, coliform bacteria, and Escherichia coli ) were monitored in 10 health functional food categories (743 items, 3,715 samples). The mean total aerobic counts of ginseng and Korean red ginseng were -0.35 and -0.74 log10 CFU/g; and their mean total coliform counts were -1.4 and -1.39 log10 CFU/g, respectively. In addition, the mean total coliform counts of fiber and protein products were -1.34 and -1.22 log10 CFU/g, respectively. However, no aerobic or coliform cells were detected in any other health functional food products (vitamins, minerals, probiotics, milk thistle extract, propolis, eicosapentaenoic acid, docosahexaenoic acid, or lutein products), and no E. coli was detected in any of the categories. These results can potentially be used to update the microbial criteria of the Health Functional Food Code.