Category Archives: microbial contamination

Research – Competitive Exclusion Prevents Colonization and Compartmentalization Reduces Transmission of ESBL-Producing Escherichia coli in Broilers

Posted on December 6, 2020 by | Leave a comment

Entero

Image CDC

Extended spectrum beta-lactamase (ESBL)-producing bacteria are resistant to extended-spectrum cephalosporins and are common in broilers. Interventions are needed to reduce the prevalence of ESBL-producing bacteria in the broiler production pyramid. This study investigated two different interventions. The effect of a prolonged supply of competitive exclusion (CE) product and compartmentalization on colonization and transmission, after challenge with a low dose of ESBL-producing Escherichia coli, in broilers kept under semi-field conditions, were examined. One-day-old broilers (Ross 308) (n = 400) were housed in four experimental rooms, subdivided in one seeder (S/C1)-pen and eight contact (C2)-pens. In two rooms, CE product was supplied from day 0 to 7. At day 5, seeder-broilers were inoculated with E. coli strain carrying blaCTX–M–1 on plasmid IncI1 (CTX-M-1-E. coli). Presence of CTX-M-1-E. coli was determined using cloacal swabs (day 5–21 daily) and cecal samples (day 21). Time until colonization and cecal excretion (log10 CFU/g) were analyzed using survival analysis and linear regression. Transmission coefficients within and between pens were estimated using maximum likelihood. The microbiota composition was assessed by 16S ribosomal RNA gene amplicon sequencing in cecal content of broilers on days 5 and 21. None of the CE broilers was CTX-M-1-E. coli positive. In contrast, in the untreated rooms 187/200 of the broilers were CTX-M-1-E. coli positive at day 21. Broilers in C2-pens were colonized later than seeder-broilers (Time to event Ratio 3.53, 95% CI 3.14 to 3.93). The transmission coefficient between pens was lower than within pens (3.28 × 10–4 day–2, 95% CI 2.41 × 10–4 to 4.32 × 10–4 vs. 6.12 × 10–2 day–2, 95% CI 4.78 × 10–2 to 7.64 × 10–2). The alpha diversity of the cecal microbiota content was higher in CE broilers than in control broilers at days 5 and 21. The supply of a CE product from day 0 to 7 prevented colonization of CTX-M-1-E. coli after challenge at day 5, likely as a result of CE induced effects on the microbiota composition. Furthermore, compartmentalization reduced transmission rate between broilers. Therefore, a combination of compartmentalization and supply of a CE product may be a useful intervention to reduce transmission and prevent colonization of ESBL/pAmpC-producing bacteria in the broiler production pyramid.

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Posted in E.coli, Enterobacteriaceae, ESBL, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, microbial contamination, Microbiology, Research

Research – Growth and Survival of Foodborne Pathogens during Soaking and Drying of Almond (Prunus dulcis) Kernels

Posted on December 6, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

The practice of soaking almonds prior to consumption is popular both commercially and at home. The food safety implications of soaking almonds was investigated through analysis of blogs and videos (n = 85 recipes) to identify both the reasons for soaking almonds and the common practices employed. Among the recipes analyzed, the most common reasons for soaking almonds (94.1%) were perceived benefits such as improved digestion and nutrient uptake. Most recipes (34.1%) suggested soaking at “room temperature” for times that ranged from 4 to 24 h or, more commonly, “overnight” (51.8%). Postsoaking drying instructions were provided in 40 recipes (47.1%). Among those providing a drying temperature (31.8%), 85% specified 66°C and lower. To evaluate the growth of foodborne pathogens during almond soaking, separate cocktails of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica were inoculated onto raw almonds or into the soak water (almonds-to-water ratios of 1:1 and 1:3 [w/v]). Populations were monitored during soaking at 15, 18, and 23°C for up to 24 h, and during postsoak drying at 66°C for 14 h (for Salmonella only). At 15°C and a 1:1 almond:water ratio, no significant population increase (P > 0.05) was observed between 0 and 24 h for any of the pathogens. At 18°C, increases of 0.63, 1.70, and 0.88 log CFU per sample were observed over 24 h for populations of E. coli O157:H7, L. monocytogenes, and Salmonella, respectively. Populations of E. coli O157:H7, L. monocytogenes, and Salmonella increased by 3.48, 3.22, and 3.94 log CFU per sample, respectively, after 24 h at 23°C. When soaked almonds were dried for 14 h at 66°C, moisture and water activity decreased from 40 to ∼6% and 0.99 to 0.60, respectively, but no significant reduction in Salmonella populations was observed. Recommendations for using shorter times (<8 h) and cooler temperatures (≤15°C) should reduce the potential for foodborne pathogens, if present, to grow during soaking of almonds.

HIGHLIGHTS
  • Online recipes described soaking conditions that would support growth of pathogens.
  • Foodborne pathogens were able to multiply in almonds soaked at 18 and 23°C.
  • Pathogen populations significantly increased after 8 h of soaking at 23°C.
  • Foodborne pathogens did not multiply in almonds soaked at 15°C for 24 h.
  • Drying soaked almonds at 66°C for 14 h did not reduce populations of Salmonella.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Pathogen, microbial contamination, Microbiology, Pathogen, pathogenic, Research, Salmonella

Research – Occurrence of Listeria monocytogenes in Counter-Sliced Turkey Meat Samples from Independent Delis in New York City

Posted on December 5, 2020 by | Leave a comment

Journal of Food Protection

Research suggests that small and independent delis are less likely to follow proper sanitation procedures, including slicer inspection, which could lead to a higher likelihood of these delis being a reservoir for Listeria monocytogenes growth and cross-contamination.    This study was undertaken to determine the incidence of L. monocytogenes in counter-sliced turkey deli meat obtained from independent delis in an urban city. Turkey deli meat, counter-sliced on site, was collected from 118 independent delis in New York City. The samples were analyzed for L. monocytogenes using USDA MLG methodology for isolation and confirmation.   The selection criteria for delis included using the city’s restaurant inspection and grading system. Two samples, from separate delis, were confirmed positive for L. monocytogenes (1.69%). Analysis of the genomic sequences of one of the samples revealed a close match to a cluster of 6 clinical isolates, which were part of an ongoing multi-state listeriosis outbreak spanning 4 different states.   The sequence of the second isolate matched a clinical isolate in a neighboring state. Both isolates were obtained from delis that did not have the top inspection grade. Although a snapshot of one urban area, this study is the first report on the current incidence of L. monocytogenes on counter-sliced deli meat from independent deli establishments. This study suggests that these delis can potentially serve as sources of L. monocytogenes contamination or contribute to downstream foodborne listeriosis. Information provided by city inspection and grading systems, in addition to the letter grade, may serve as a tool to identify delis with potential L. monocytogenes contamination issues and serve as a basis for product and environmental sampling by public health authorities.

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Posted in Bacteria, bacterial contamination, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Pathogen, Food Safety, Food Testing, Listeria, Listeria monocytogenes, microbial contamination, Microbiology, Research

Research – Use of a Novel Sanitizer To Inactivate Salmonella Typhimurium and Spoilage Microorganisms during Flume Washing of Diced Tomatoes

Posted on December 4, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

As demand for fresh-cut produce increases, minimizing the risk of salmonellosis becomes critical for the produce industry. Sanitizers are routinely used during commercial flume washing of fresh-cut produce to minimize cross-contamination from the wash water. This study assessed the efficacy of a novel sanitizer blend consisting of peracetic acid (PAA; OxypHresh 15) with a sulfuric acid–surfactant (SS) antimicrobial (PAA-SS; ProduceShield Plus) against Salmonella during simulated commercial washing of diced tomatoes. Triplicate 9.1-kg batches of Roma tomatoes were dip inoculated in a two-strain avirulent Salmonella cocktail (Salmonella Typhimurium LT2 and MHM112) to achieve 5 to 6 log CFU per tomato and air dried for 2 h. After mechanical dicing, the tomatoes were washed in a pilot-scale processing line for 60 s with or without an added organic load in 90 ppm of PAA-SS (pH 1.8), SS at pH 1.8, 90 ppm of PAA, 5 or 10 ppm of free chlorine or sanitizer-free water as the control. Overall, PAA-SS (1.75 ± 0.75 log CFU/g) was significantly (P ≤ 0.05) more effective than water (0.69 ± 0.42 log CFU/g), chlorine (0.35 ± 0.36 log CFU/g), or SS (0.36 ± 0.19 log CFU/g) in reducing Salmonella. After washing for 20 s, PAA-SS was the only sanitizer to show a significant (P ≤ 0.05) reduction (1.93 ±0.59 log CFU/g) in Salmonella. All wash water samples were negative for Salmonella, except for 5 and 10 ppm of chlorine and the water control. Using PAA-SS with an organic load, yeast and mold populations were below the limit of detection (1.40 log CFU/g) and significantly (P ≤ 0.05) lower on diced tomatoes after 14 days of refrigerated storage compared with the other treatments (8.37 ± 0.08 log CFU/g), with SS at pH 1.8 (3.91 ± 0.93 log CFU/g) most effective against yeast and mold in the absence of an organic load. On the basis of these findings, the safety and shelf life of commercially washed diced tomatoes can be improved with PAA-SS.

HIGHLIGHTS
  • PAA-SS yielded lower Salmonella populations in diced tomatoes than did chlorine (P ≤ 0.05).
  • Salmonella was not detected in the wash water using PAA-SS.
  • PAA-SS decreased Salmonella 1.93 log after 20 s of washing.
  • PAA-SS yielded lower (P ≤ 0.05) yeast and mold populations after 14 days of storage.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, microbial contamination, Microbiology, Research, Salmonella, Technology

Research – Reduction of Norovirus in Foods by Nonthermal Treatments: A Review

Posted on December 4, 2020 by | Leave a comment

Journal of Food Protection

ABSTRACT

Human noroviruses are enteric pathogens that cause a substantial proportion of acute gastroenteritis cases worldwide regardless of background variables such as age, ethnicity, and gender. Although person-to-person contact is the general route of transmission, foodborne infections are also common. Thorough cooking eliminates noroviruses, but several food products such as berries, leafy vegetables, and mollusks undergo only limited heat treatment, if any, before consumption. Novel applications of nonthermal processing technologies are currently being vigorously researched because they can be used to inactivate pathogens and extend product shelf life with limited effects on nutrient content and perceived quality. These technologies, adopted from several industrial fields, include some methods already approved for food processing that have been applied in the food industry for years. However, a majority of the research has been conducted with bacteria and simple matrixes or surfaces. This review focuses on elimination of norovirus in food matrixes by use of nonthermal technologies in four categories: high hydrostatic pressure, light, irradiation, and cold atmospheric plasma. We discuss the properties of noroviruses, principles and inactivation mechanisms of select technologies, and main findings of relevant studies. We also provide an overview of the current status of the research and propose future directions for related work.

HIGHLIGHTS
  • High pressure processing is the most promising nonthermal treatment for noroviruses.
  • High pressure processing, ionizing radiation, and UVC light can reduce noroviruses in foods.
  • Treatments used to eliminate viruses can impair food product quality.
  • Optimal virus elimination strategies should be validated independently for each food product.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Technology, Food Virus, microbial contamination, Microbiology, Norovirus, Research, Technology, Virus

Portugal – Legionnaires’ disease update: Additional cases/death recorded

Posted on December 4, 2020 by | Leave a comment

Outbreak News Today

CDC legionella

In a follow-up on the Legionnaires’ disease outbreak in northern Portugal region of Greater Porto, officials report from October 29 through November 29, 88 registered cases, including 10 deaths.

The outbreak, which has affected the cities of Matosinhos, Vila do Conde and Póvoa de Varzim, has decreased after the cooling towers of an industry in Matosinhos were disconnected where the bacteria was detected.

“Since the operation of the aforementioned cooling towers was suspended, there has been a marked decrease in the number of cases of Legionnaires’ disease in the aforementioned geographical area,” ARS / Norte said in a statement this Sunday.

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Posted in Bacteria, bacterial contamination, Contaminated water, Food Micro Blog, Food Microbiology Blog, microbial contamination, Microbiology, Water, water microbiology, Water Safety

RASFF Alert – E.coli – Japanese Clams

Posted on December 4, 2020 by | Leave a comment

European Food Alerts

RASFF

high count of Escherichia coli (1700 MPN/100g) in japanese clams from Portugal in Spain

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Posted in Bacteria, bacterial contamination, E.coli, food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Pathogen, Food Poisoning, food recall, Food Safety, Food Safety Alert, Food Testing, Food Toxin, microbial contamination, Microbiology, RASFF

RASFF Alerts – Animal Feeds – Salmonella – Organic Soya Cakes – Rapeseed Expeller – Dried Dog Food – Rapeseed Meal

Posted on December 4, 2020 by | Leave a comment

European Food Alerts

RASFF

Salmonella (presence /25g) in organic soya cakes from Belgium in Germany

RASFF

Salmonella enterica ser. Mbandaka (presence /25g) in rapeseed expeller from Estonia in Finland

RASFF

Salmonella enterica ser. Livingstone (presence /25g) in dried dog food from Germany in Finland

RASFF

Salmonella enterica ser. Livingstone (presence /25g) in rapeseed meal from Germany in Sweden

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Posted in Animal Feed, Food Micro Blog, Food Microbiology Blog, Food Microbiology Testing, microbial contamination, Microbiology, RASFF, Salmonella, Salmonella Dog Food

Research – Practical application of bacteriophage in food manufacturing facilities for the control of Listeria sp.

Posted on December 3, 2020 by | Leave a comment

Wiley Online

Listeria monocytogenes is a foodborne pathogen with the ability to persist and form biofilm matrices in processing environments of food manufacturing facilities. Bacteriophages are bacterial viruses with host specific lethality. Published research on the application of phage to control Listeria sp. in manufacturing environments is limited. In this study, we have assessed the capacity of bacteriophage P100 (Listex™) to reduce incidence of Listeria sp. in the ready‐to‐eat (RTE) environment of refrigerated (4°C) and ambient (20°C) temperature facilities using two different application strategies. A moderate application applied as a single treatment every 24 hr over three days (2 × 107 PFU/ml) and an intensified application applied once every 6 hr over a 24 hr period (1 × 108 PFU/ml). Environmental nonfood contact surface (NFCS) samples were collected and analyzed for the presence of Listeria sp. before and after treatment. When the moderate treatment protocol was applied the incidence of positives decreased from 51.3 to 17.5% in the 4°C environment and from 67.5 to 23.1% in the 20°C production area. For the intensified phage treatment method, the initial positive rate in the 4°C environment ranged from 5 to 47.5%, with an overall 43% reduction in Listeria sp. In the 20°C facility, initial environmental Listeria sp. ranged from 15 to 50%, with an overall reduction of 32% after treatment with phage P100. Data indicate the application of Listeria specific phage P100 in RTE food production environments by either the moderate or intensified application method can reduce incidence and be considered an additional intervention strategy for controlling this pathogen on NFCS.

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Posted in Biofilm, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Testing, Food Technology, Listeria, Listeria monocytogenes, microbial contamination, Microbiological Risk Assessment, Microbiology, Technology

Research – Mycotoxins in Beverages

Posted on December 3, 2020 by | 2 comments

MDPI

Mycotoxins are secondary metabolites produced by fungi that contaminate raw materials such as cereals, fruits, dried fruits, coffee, and grapes when they have been produced or maintained in a temperature and/or humidity conditions that favour fungi growth. In general, mycotoxins are very resistant to temperature and remain stable during food preparation and processing [1].Therefore, food prepared from contaminated raw materials can retain the levels of these compounds.Several beverages are produced based on raw materials prone to be contaminated, such as beer from cereals, wine from grapes, coffee, and more. Moreover, and due to the fact that one fungal speciescan produce various of these metabolites [2], the most likely scenario is the co-occurrence of several mycotoxins in one food product.

Mycotoxins have different toxic effects on human health. They can be divided into acute effects,due to the ingestion of high levels of toxins in a short time period, and into chronic effects, due to the ingestion of low quantities for a long time. These chronic effects are the most common ones and they have been described as hepatotoxicity, immune diseases, carcinogenicity, genotoxicity, endocrine andreproductive effects, mutagenicity, teratogenicity, nausea, vomiting and diarrhea, among others [2].All the above make the presence of these compounds in human foods a global problem regarding food safety and also regarding economics, due to the loss of lots of contaminated raw materials or food products and its impact on global trade [3].In order to protect human health, legislative organisms promote the monitorization of these toxins in raw materials and foods, along with the regulation of maximum levels that can be present in some food products.

This Special Issue “Mycotoxins in Beverages” comprises three research articles and three reviews related to the presence of these toxins in beverages and covers different aspects. The research articles are devoted to the presence of mycotoxins in beer and milk. The reviews collect, on the one hand,information regarding mycotoxin presence in wine and in beverages obtained from tropical crops, and,on the other, new approaches for detecting ochratoxin A and other compounds in beverages.

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Posted in Aflatoxin, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Microbiology Research, Food Microbiology Testing, Food Toxin, Fusarium Toxin, microbial contamination, Microbiology, Mold Toxin, Mould Toxin, Mycotoxin, Ochratoxin