Category Archives: Food Microbiology Research

Research – COVID-19 and the Food Industry

New Food Magazine

While we hear reassurance from food safety bodies such as the European Food Safety Authority (EFSA) that “there is currently no evidence that food is a likely source or route of transmission of COVID-19,” we are all still, surely, feeling a little uncertain. Is our food truly safe? What impact will this unprecedented pandemic have on the food and beverage industry further down the line?

EFSA’s Chief Scientist, Marta Hugas, said that “experiences from previous outbreaks of related coronaviruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), show that transmission through food consumption did not occur” and that we – industry and consumer alike – can be confident that this translates to COVID-19.

Research – Thermal Resistance of Foodborne Pathogens and Enterococcus faecium NRRL B-2354 on Inoculated Pistachios

JFP

Process control validations require knowledge of the resistance of the pathogen(s) of concern to the target treatment, and, in some cases, the relative resistance of surrogate organisms. Selected strains of Escherichia coli O157:H7 (five strains), Listeria monocytogenes (five strains), and Salmonella enterica (five strains) as well as Salmonella Enteritidis phage type (PT) 30 and nonpathogenic Enterococcus faecium NRRL B-2354 were inoculated separately (as individual strains) onto inshell pistachios. The thermal tolerance of each strain was compared via treatment of inoculated pistachios to hot oil (121°C) or hot water (80°C) for 1 min. Survivor curves in hot oil or hot water (0.5 to 6 min, n = 6 to 15) were determined for one or two of the most resistant strains of each pathogen, as well as E. faecium NRRL B-2354 and Salmonella Enteritidis PT 30, and the Weibull model was fit to the data. A pilot-scale air-impingement oven was used to compare the thermal tolerance of E. faecium NRRL B-2354 and Salmonella Enteritidis PT 30 on pistachios with or without a brining pretreatment and at either dry (no steam) or 30% humidity (v/v) oven conditions. No significant difference in the time to a 4-log reduction in hot oil or hot water was predicted for any of the strains evaluated, on the basis of the 95% confidence interval. In the pilot-scale oven, E. faecium NRRL B-2354 was more thermally resistant than Salmonella in a broad set of differing treatments, treatment times, and temperatures. Salmonella is a suitable target pathogen of concern in pistachios for thermal processes because no other pathogen tested was more thermally resistant under the conditions evaluated. E. faecium NRRL B-2354 was at least as thermally resistant as Salmonella under all conditions evaluated, making it a good potential surrogate for Salmonella on pistachios.

Research – Occurrence and characteristics of Listeria monocytogenes in ready-to-eat meat products in Poland

JFP

Listeria monocytogenes is a potential hazard for food safety and therefore public health. The aim of the present study was to determine the prevalence and characteristics of L. monocytogenes in Polish ready-to-eat (RTE) meat products in retail. Among the 184 439 food samples collected within the framework of national official control and monitoring program only 0.3% were  positive for L. monocytogenes. A significant group of products that did not meet the criteria were RTE meat products. This group accounted for 40% of all non compliant samples. A total of 70 L. monocytogenes isolates from RTE meat products (meat, sausages and delicatessen products with meat) were examined. The majority of the tested isolates (51%) belonged to serogroup 1/2a-3a, followed by 1/2c-3c (21%), 1/2b-3b-7 (14%) and 4ab-4b-4d-4e (13%). Serogroup 4a-4c was not present among the tested isolates. All L. monocytogenes isolates harbored the virulence-associated genes inlA, inlC, inlJ and lmo2672 . The llsX marker was detected in twelve of 70 (17%) isolates. Ampicillin resistance was the most common resistance phenotype and was identified in 83% of L. monocytogenes isolates. A low incidence of resistance to amoxicillin/clavunate acid (6% isolates)  was also detected. All L. monocytogenes isolates were susceptible to chloramphenicol, gentamicin, ciprofloxacin, meropenem, sulfamethoxazole-trimethoprim, tetracycline and erythromycin. This work provides useful information regarding contamination of RTE meat products with L. monocytogenes, which may have implications for food safety risk.

Research – Researchers turn to air sampling to detect Campylobacter in chicken flocks

Food Safety News

 

A project led by the National Food Institute, Technical University of Denmark, has developed a test method to improve the likelihood of identifying Campylobacter-positive chicken flocks.

Being able to identify Campylobacter-positive flocks before they arrive at the slaughterhouse allows them to be slaughtered after the negative flocks to avoid cross-contamination along the production line.

The method was worked on in the EU project, AIR-SAMPLE, which began in January 2018 and runs until June 2020. Other partners are the Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise “Giuseppe Caporale” in Italy, Veterinary Research Institute in the Czech Republic, National Veterinary Research Institute in Poland and Norwegian Veterinary Institute.

The aim was to develop and validate air sampling as a low-cost and multi-purpose alternative to fecal droppings or boot swabs for surveillance, monitoring and eradication of Campylobacter in confined and biosecured broiler production operations.

USA – Mountain Rose Herbs Recalls Organic Kudzu Root Herbal Supplement Due to Possible Health Risk

FDA

Mountain Rose Herbs (MRH) of Eugene, Oregon is recalling all sizes of its Organic Kudzu Root Herbal Supplement from Lot #24247-X and #24247 because they have the potential to be contaminated with Salmonella, an organism which can cause serious and sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems. Healthy persons infected with Salmonella often experience fever, diarrhea (which may be bloody), nausea, vomiting and abdominal pain. In rare circumstances, infection with Salmonella can result in the organism getting into the bloodstream and producing more severe illnesses such as arterial infections (i.e., infected aneurysms), endocarditis and arthritis.

The product comes in a clear plastic or poly-woven bag, net weight ranges from 4 oz. to 50 lbs., marked with lot #24247-XExternal Link Disclaimer and #24247External Link Disclaimer. The lot number is located on the principal display panel on the lower left of the label (see linked label examples).

The recalled Organic Kudzu Root Herbal Supplement was distributed to customers who ordered from mountainroseherbs.com, purchased at the company’s retail shop in Eugene, Oregon, or placed mail orders by phone or fax between the dates of 6/17/2019 to 3/2/2020. It is possible MRH customers also resold the Kudzu Root to their own clientele.

Mountain Rose Herbs also distributed product directly to customers in AL, AR, AZ, CA, CO, CT, FL, GA, HI, IA, ID, IL, IN, KS, KY, MA, MD, ME, MI, MN, MO, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OR, PA, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY, British of Columbia, Nova Scotia, Ontario, and Quebec of Canada.

No illnesses have been reported to date. We are initiating this recall as a precautionary measure. The potential for contamination was noted after testing by the company revealed the presence of Salmonella in a portion of its ingredients in inventory. Production of the product has been suspended while we continue our investigation.

We conduct this recall with the knowledge of the U.S. Food and Drug Administration.

Consumers who have purchased the affected Kudzu Root are urged not to consume and should return product to the place of purchase for a full refund. Consumers with questions may contact Mountain Rose Herbs at 1-800-879-3337 X.109, Mon-Fri, 8 am-4:30 pm PT, or at claims@mountainroseherbs.com.

Tanzania – Fast-Track East African Community Aflatoxin Law to End Toxic Menace

All Africa

The war on aflatoxins in East Africa is intensifying as member-states of the East African Community (EAC) strategise through regular consultative meetings on how best to surmount the malady in the region.

Aflatoxins are a family of toxins produced by certain fungi which include – but are by no means limited to – ‘Aspergillus flavus’ and ‘Aspergillus parasiticus,’ that are abundant in warm and humid regions across the world. The highly-carcinogenic toxins are mostly found on agricultural crops such as maize, as well as cottonseeds, peanuts, cashew nuts, walnuts, pine nuts, coconuts, almonds, etc.

What with maize being a staple food in the region – and nuts being popular ingestibles for all age groups – aflatoxins are a huge threat to humanity. Hence the concerns and dire need to wipe out aflatoxins in our region and the African continent as a whole…

 

Kenya – Aflatoxin Levels in Maize Worry Kebs and Millers

All Africa

The Kenya Bureau of Standards (Kebs) and millers have raised concerns over high levels of aflatoxin in maize.

They say most of the maize contains unacceptable levels of the toxin, making it unfit for human consumption.

Poor storage facilities and heavy rains in maize-growing zones have contributed to the problem, said Dr Henry Rotich, the director of meteorology and testing at Kebs.

“Regular inspections and tests for aflatoxin are carried out to ensure maize flour and other products meet recommended standards,” he said.

“In Kenya, the allowable aflatoxin level in maize is 10 parts per billion. Anything above that is unacceptable.”

Research – Compatibility of commercially produced protective cultures with common cheesemaking cultures and their antagonistic effect on foodborne pathogens

JFP

The documented survival of pathogenic bacteria including Listeria monocytogenes (LM), shiga toxin-producing Escherichia coli (STEC), and Salmonella during the manufacture and aging of some cheeses highlights the need for additional interventions to enhance food safety. Unfortunately, few interventions are compliant with the Standards of Identity for cheese. Protective bacterial cultures (PC) represent actionable, natural interventions. However, supportive data for commercially produced PCs regarding their efficacy against pathogens and potential antagonism with each other and cheesemaking cultures are scant, thereby impeding their potential use by the cheese industry. The overall objective of this study was to identify commercially produced PCs that exert antimicrobial activity towards pathogens with minimal impact on beneficial cheese microbes. Direct antagonism and agar well diffusion assays were used to determine the impact of 10 commercially produced PCs on the growth of starter cultures and cultures of ripening bacteria and fungi. Deferred antagonism was used to evaluate the potential for antimicrobial effects against LM, STEC, and Salmonella. PCs and starter cultures were co-cultured in UHT milk to determine the effects of co-culture on starter acidification profiles when incubated according to a simulated cheese-making temperature profile (4 h at 35°C followed by 20 h at 20°C). Compatibility assays suggest that PC antagonism is microbe and strain specific. Only one PC negatively impacted the acidification of the starters tested. PC antagonism of ripening bacteria and fungi growth varied but was consistent within species. All PCs displayed deferred inhibition of LM, STEC, and Salmonella growth but to varying degrees. These data identify commercial PCs with potential for the control of pathogens and characterize their compatibility with cheesemaking cultures for future use by cheesemakers and investigations of their efficacy in the production of cheese.

Research – Biofilm formation by South African non-O157 Shiga toxigenic Escherichia coli on stainless steel coupons

NRC

This study examined the biofilm-forming ability of six non-O157 Shiga-toxin-producing Escherichia coli (STEC) strains: O116:H21, wzx-Onovel5:H19, O129:H21, O129:H23, O26:H11, and O154:H10 on stainless steel coupons after 24, 48, and 72 h of incubation at 22 °C and after 168 h at 10 °C. The results of crystal violet staining revealed that strains O129:H23 and O154:H10 were able to form biofilms on both the submerged surface and the air–liquid interface of coupons, whereas strains O116:H21, wzx-Onovel5:H19, O129:H21, and O26:H11 formed biofilm only at the air–liquid interface. Viable cell counts and scanning electron microscopy showed that biofilm formation increased (p < 0.05) over time. The biofilm-forming ability of non-O157 STEC was strongest (p < 0.05) at 22 °C after 48 h of incubation. The strongest biofilm former regardless of temperature was O129:H23. Generally, at 10 °C, weak to no biofilm was observed for isolates O154:H10, O116:H21, wzx-Onovel5:H19, O26:H11, and O129:H21 after 168 h. This study found that temperature affected the biofilm-forming ability of non-O157 STEC strains. Overall, our data indicate a high potential for biofilm formation by the isolates at 22 °C, suggesting that non-O157 STEC strains could colonize stainless steel within food-processing facilities. This could serve as a potential source of adulteration and promote the dissemination of these potential pathogens in food.

USA – Norovirus outbreak reported on Royal Caribbean’s Grandeur of the Seas

Outbreak News Today norovirus-1080x655

Federal health officials report investigating a norovirus outbreak onboard Royal Caribbean International vessel, Grandeur of the Seas.

The outbreak on the March 7–March 19, 2020 voyage has sickened 83 passengers and six crew members, who developed symptoms of vomiting and diarrhea.

Specimens have been collected, tested onboard, and found to be positive for norovirus. The specimens will be sent to CDC for genome sequencing.