Category Archives: Food Technology

Research – Evaluation of Inactivating Norovirus, Hepatitis A, and Listeria monocytogenes on Raspberries by Sanitizer Spray

Posted on April 26, 2019 by | Leave a comment

Journal of Food Protection

Reducing the risk of contamination with foodborne pathogens is paramount in maintaining safety of produce. The raspberry industry uses chlorine spray as a control measure before conveying freshly picked red raspberries into individually quick frozen units. However, the efficacy of sanitizer spray treatment to inactivate norovirus, hepatitis A virus (HAV), and Listeria monocytogenes on raspberries has not been characterized. In this study, a laboratory-scale spray bar device was fabricated to simulate industrial settings. Fresh raspberries were spot inoculated with murine norovirus (MNV, a norovirus surrogate), HAV, or L. monocytogenes and sprayed with 50 ppm of chlorine or 80 ppm of peroxyacetic acid (PAA). Surviving pathogens were enumerated after spray or postspray frozen storage at −20°C for 1 and 24 h. Chlorine and PAA spray treatments reduced MNV and L. monocytogenes from raspberries by 0.2 and 0.6 log but had no effect on HAV. During frozen storage after spray treatment, the residual PAA on the fruit surfaces further reduced MNV and L. monocytogenes, achieving a total reduction of approximately 0.6 and 3.0 log, respectively. HAV levels were not affected by frozen storage after PAA or chlorine spray treatment. The findings were supported by the sanitizer decay results showing that PAA decayed more slowly than active chlorine on raspberry surfaces. Submerging washes conducted as comparisons showed higher reduction of pathogens from raspberry surfaces than similar respective sanitizer spray treatments. The results suggest that PAA could contribute to raspberry postharvest sanitation, aiding in risk reduction of pathogen contamination prior to entering an individually quick frozen un

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Posted in food contamination, Food Hygiene, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Safety, Food Technology, Food Testing, Hepatitis A, Listeria, Listeria monocytogenes, Norovirus, Uncategorized

Research – Inactivation of Staphylococcus aureus and Escherichia coli in milk by different processing sequences of ultrasound and heat

Posted on April 6, 2019 by | Leave a comment

Wiley Online

Abstract

Different processing sequences of ultrasound and heat were applied for the inactivation of Staphylococcus aureus and Escherichia coli in milk. The changes in whey protein content, particle size, zeta potential, pH, viscosity, and color values were studied to evaluate the effects on the quality of milk. Results indicated ultrasound treatment (600 W, 5 min) with postheating (63 °C 5 min) reduced S. aureus and E. coli by 1.58 and 2.02 log cfu/ml, respectively, but yielded 0.26 and 0.19 log cfu/ml sublethal S. aureus and E. coli. Milk preheated to 63 °C (5 min) followed by ultrasound (600 W, 5 min) showed 1.17 and 1.68 log reductions for S. aureus and E. coli, respectively, and the sublethal S. aureus and E. coliwere reduced to 0.16 and 0.09 log cfu/ml. The increased cavitation effects make the simultaneous treatment (600 W, 63 °C, 5 min) the most effective approach in killing S. aureus and E. coli, causing 1.67 and 2.16 log reductions, respectively, and producing negligible sublethal bacteria. The simultaneous treatment was also able to improve some physical–chemical properties of milk; smaller particle size and whiter color were achieved. However, whey protein and stability indices of milk were slightly deteriorated by this approach.

Practical applications

In food processing fields, thermosonication can serve as an alternative processing technique to thermal pasteurization. Especially, the simultaneous treatment of ultrasound and heat showed best inactivation effect for viable and sublethal cells, while maintaining the overall milk quality in the meantime. The results of this research may be useful for the treatment of various bacterial contamination and give the guidance for milk processing

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Posted in E.coli, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Poisoning, Food Safety, Food Technology, Food Testing, Staphylococcus aureus, Uncategorized

Research – Effects of Sodium Chloride or Calcium Chloride Concentration on the Growth and Survival of Escherichia coli O157:H7 in Model Vegetable Fermentations

Posted on March 31, 2019 by | Leave a comment

Journal of Food Protection

Salt concentration has long been considered an important factor for the quality of fermented vegetable products, but the role of salts in bacterial growth and death during vegetable fermentation remains unclear. We compared the effects of various sodium chloride (NaCl) concentrations, including 1 M (6%) NaCl used in commercial cucumber fermentations and 0.34 M (2%) NaCl used in cabbage and other ready-to-eat vegetable fermentations, on the growth and death of lactic acid bacteria (LAB) of the genus Lactobacillus and pathogenic Escherichia coli (Shiga toxin–producing E. coli, or STEC) strains. We also investigated calcium chloride (CaCl2) salt conditions. CaCl2 is being used at 0.1 M (1.1%) in low-salt commercial cucumber fermentations that lack added NaCl. STEC strains have previously been shown to be among the most acid-resistant pathogens in fermented or acidified vegetables. The data showed that 1.1% CaCl2, and especially 1% NaCl, had a stimulatory effect on the growth rates of STEC and LAB compared with a no-salt control, but higher NaCl concentrations decreased growth rates for STEC; to a lesser extent, LAB growth rates were also reduced. For most salt concentrations tested, maximum cell densities achieved during growth of STEC were reduced compared with those of the no-salt controls, whereas LAB mostly had cell densities that were similar to or greater than those of the no-salt controls. No consistent pattern was observed when comparing death rates with salt type or concentration for the STEC or LAB cocktails undergoing lactic acid stress (50 or 350 mM, respectively) at pH 3.2 and when comparing STEC survival in competitive culture experiments with LAB. For vegetable fermentation safety concerns, the results suggest that an important effect of salt addition is enhancement of the growth of LAB compared with STEC strains. Further research will be needed to determine factors influencing STEC survival in competition with LAB in vegetable fermentations.

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Posted in E.coli, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Technology, Food Testing, lactic acid bacteria, microbial contamination, STEC, Uncategorized

Europe – ECDC – Multi-country cluster of Listeria monocytogenes ST1247 in five EU countries

Posted on March 27, 2019 by | Leave a comment

ECDC

CDC has identified a microbiological link between an outbreak of nine Listeria monocytogenes ST1247 cases in Denmark and nine additional cases reported between 2014 and 2018 in Estonia (2 cases) Finland (2), France (1) and Sweden (4).

ECDC has identified a microbiological link between an outbreak of nine Listeria monocytogenes ST1247 cases in Denmark and nine additional cases reported between 2014 and 2018 in Estonia (2 cases) Finland (2), France (1) and Sweden (4).  In Denmark, the outbreak investigation is led by Statens Serum Institut (SSI), the Danish Veterinary and Food Administration and the DTU Food Institute.

Whole Genome Sequencing (WGS) analysis performed at the national level and by ECDC found all isolates from the 18 cases within two allelic differences from each other (core genome MLST using Moura scheme, 1540 of 1748 loci detected in all 18 isolates). The latest case was reported in Denmark in February 2019 (Figure 1).

Figure 1: Distribution of Listeria monocytogenes isolates by country and time of reporting 2014-2019 (n=18)

Figure 1: Distribution of Listeria monocytogenes isolates by country and time of reporting 2014-2019 (n=18)

A large-scale study led by ECDC on whole genome sequencing shows that most listeria outbreaks such as this one remain undetected. The study, published in 2018, suggests that more than half of the severe listeriosis cases in the European Union belong to clusters, many of which are not being picked up fast enough by the current surveillance system.

Listeria monocytogenes causes listeriosis, which primarily affects pregnant women, newborns, and adults with a weakened immune system. Listeriosis is a relatively rare but potentially severe food-borne disease that has been reported in increasing numbers in the EU/EEA countries since 2008. In 2016, 2 536 cases were reported, including 247 deaths.

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Posted in food contamination, food death, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Technology, Food Testing, Listeria, Listeria monocytogenes, listeriosis, MLST, Uncategorized, Whole Genomic Sequencing

Information – NEW TOOL LAUNCHED TO IMPROVE CONSUMER FOOD SAFETY AT HOME Safe Recipe Style Guide to Provide Food Safety Instructions in Recipes

Posted on March 25, 2019 by | Leave a comment

Safe Recipe Guide

(Orlando, FL – March 7, 2019) – At one of our nation’s largest gatherings of food safety professionals today, the Partnership for Food Safety Education (PFSE) launched a new tool that is expected to dramatically improve consumers’ food safety behaviors at home. PFSE announced the release of a new Safe Recipe Style Guide at the 2019 Consumer Food Safety Education Conference where more than 400 public and private sector experts are convened to address how to improve food safety behaviors.

The Safe Recipe Style Guide is designed for use by any recipe writer – professional recipe developers and food journalists – who writes and publicizes recipes for distribution to the public. It provides specific, concise recipe text to address the four major areas of most food safety violations in home kitchens: temperature, handwashing, cross contamination and produce handling. It can be found online at www.saferecipeguide.org.

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Posted in Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Safety, Food Technology, Uncategorized

Research – Food safety: Dung beetles and soil bacteria reduce risk of human pathogens

Posted on March 23, 2019 by | Leave a comment

Science Daily

Food safety regulations increasingly pressure growers to remove hedgerows, ponds and other natural habitats from farms to keep out pathogen-carrying wildlife and livestock. Yet, this could come at the cost of biodiversity. New research encourages the presence of dung beetles and soil bacteria at farms as they naturally suppress E. coli and other harmful pathogens before spreading to humans.

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Safety, Food Technology, Food Testing, Uncategorized

USA – Butterball Ground Turkey Salmonella Schwarzengrund Outbreak Sickens 6

Posted on March 18, 2019 by | Leave a comment

Food Poisoning Bulletin

The Butterball ground turkey Salmonella Schwarzengrund outbreak first reported in a USDA recall notice has sickened 6 people in 3 states, according to the Centers for Disease Control and Prevention (CDC). One person has been hospitalized. No deaths have been reported.

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Posted in food bourne outbreak, food contamination, Food Hygiene, Food Illness, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, food recall, Food Safety, Food Safety Alert, Food Technology, Food Testing, foodborne outbreak, foodbourne outbreak, Salmonella, Uncategorized

Research – Microbiological and chemical quality of ice used to preserve fish in Lisbon marketplaces

Posted on March 17, 2019 by | Leave a comment

Wiley Online

Abstract

Ice is widely used to preserve fish on markets, playing a major role in the food industry. If manufactured, stored or distributed in inadequate sanitary conditions, it can represent a considerable health risk for both consumers and professionals. The present study characterizes ice used in marketplaces, on microbiological and chemical parameters. The aim was to assess potential risks on occupational exposure and consumer safety and therewith plan orientation guidelines. Sampling took place in 18 marketplaces in Lisbon, with ice samples collected at three different stages—production (n = 29), storage (n = 30), and product‐contact (n = 29). No significant contamination was found in production and storage stages, demonstrating that ice production and storage procedures are adequate regarding sanitary conditions. With exception for Salmonella, significantly higher concentrations of microbial parameters were identified in product‐contact stages, specifically Total Coliforms (548 MPN/100 mL), Escherichia coli (1 MPN/100 mL), Enterococci (29 MPN/100 mL), Staphylococcus aureus (271 CFU/100 mL), HPC at 5°, 22°, and 37° (>301 CFU/mL). Our study also shows that the majority of samples from ice production and storage comply with national regulations regarding drinking water quality. Yet, occupational health and consumer risks may still exist at the final product‐contact stage, as significant contamination was detected..

Practical applications

The present study can be used as a model for ice quality monitoring in fish preservation, serving as a tool for quality control and fast contamination detection during the several process stages.

This monitoring model is an important contribution for assuring the safety of the preserved products, as well as, occupational health improvement and consumer risk protection.

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Posted in Coliforms, E.coli, Enterococcus, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Technology, Food Testing, Salmonella, Staphylococcus aureus, Uncategorized

Research – Microbial composition changes on the surface of strawberries from the field and market by 16SrDNA sequencing

Posted on March 16, 2019 by | Leave a comment

Wiley Online Library

Abstract

Fresh fruit is indispensable as a part of a daily diet; however, it commonly harbors large and diverse bacteria populations, including some important human pathogens. To determine the microbial composition on the surface of a strawberry, and structural changes of microbial composition from the field and market, 16SrDNA sequencing of 32 samples collected from production field (B) and market (M), which were divided into Groups I through III, was performed in this study. As a result, the 3,073 operational taxonomic units (OTUs) were clustered, and 5 phyla and 10 genera were dominant across all samples. When comparing I.B with I.M, Acinetobacter, Buchnera, and Bradyrhizobiumwere higher in I.B (p > 0.05), while Bacteroides, Pseudomonas, and Shewanella were higher in I.M (p > 0.05). Comparing II.B with II.M, Campylobacter was dominant in II.B, while most of the top10 genera decreased in II.M, except Acinetobacter, which presented an overwhelming richness, with an average relative abundance of 65.657 ± 1.071% (p = 0.002). Comparing III.B with III.M, Buchnera decreased in III.M, while Shewanella increased. Additionally, a certain number of opportunistic pathogens that included Acinetobacterwere present in some samples. Therefore, analysis of microbial composition changes on the surface of strawberries is important for ensuring the biological safety of strawberries.

Practical applications

This paper focused on determining the microbial composition on the surface of strawberry and comparing its structural changes of microbial composition from the field and market. The study results will be helpful for ensuring the biological safety of strawberries as well as a scientific basis for the traceability of microbial contamination of strawberries.

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Technology, Food Testing, Uncategorized

Research – Effects of Lactobacillus plantarum, Pediococcus acidilactici, and Pediococcus pentosaceus on the Growth of Listeria monocytogenes and Salmonella on Alfalfa Sprouts

Posted on March 5, 2019 by | Leave a comment

Journal of Food Protection alfalfa

ABSTRACT

The germination conditions of sprouted vegetables consisting of relatively high temperatures and humidity, low light, and abundance of nutrients are ideal for pathogen survival and growth. The continual occurrence of outbreaks and recalls associated with sprout vegetables indicate additional measures are needed to improve product safety. The objective of this study was to evaluate the efficacy of a mixture of Lactobacillus plantarum, Pediococcus acidilactici, and Pediococcus pentosaceus (LPP) against Listeria monocytogenes and Salmonella on alfalfa sprouts during 5 days of sprouting at 20°C and its influence on sprout quality. Alfalfa seeds were inoculated with L. monocytogenes or Salmonella (each at 1 and 3 log CFU/g) and LPP (7 log CFU/g). Populations of LPP were maintained at 7.5 to 8.0 log CFU/g throughout sprouting. LPP had a significant effect on the growth of L. monocytogenes and Salmonella (P < 0.05). After 5 days of sprouting, populations of L. monocytogenes at an initial concentration of 1 and 3 log CFU/g of seeds treated with LPP were approximately 4.5 and 1.0 log CFU/g less than the untreated seeds, respectively. Populations of Salmonella at an initial concentration of 1 and 3 log CFU/g were 1.0 log CFU/g less than the control. LPP did not compromise the yield, seedling length, or pH of the sprouts.

HIGHLIGHTS

  • Listeria populations on LPP-treated sprouts were 4.5 log less than untreated seeds.

  • LPP treatment reduced Salmonella populations by 1 log compared with controls.

  • LPP did not influence sprout quality.

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Posted in Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Safety, Food Technology, Food Testing, Listeria, Listeria monocytogenes, Salmonella, Uncategorized