Category Archives: Food Microbiology Research

Research- Fish, Tilapia, and Shigellosis: A review


Foodborne diseases are considered a relevant issue in health around the world due to their incidence, mortality and negative effects on the economic and productive sector. Fish is considered a food of high nutritional quality, being of global production, distribution and commercialization mainly for human consumption. Among the fish worldwide obtained from capture fisheries and mainly aquaculture for human consumption is Tilapia, due to the adaptability of this fish under cultivation conditions in addition to the fact that its meat is of quality and accessible economic value. Fish due to its composition, is highly susceptible to deterioration and contamination by different hazards throughout the food chain, putting the safety of products and public health at risk. Shigellosis is among the diseases that may be contracted from the consumption of food contaminated by bacteria of the genus Shigella spp.; food contamination is mainly related to inadequate or non-hygienic conditions and practices in the production, processing and handling of food. Therefore, the purpose of this review is to provide a general perspective of foodborne diseases, especially shigellosis, causal agents, conditioning factors, related foods such as fish, as well as control and preventive actions in order to protect the food safety and public health.

USA – Outbreak sickens dozens; no cause found; investigation closed

Food Safety News

The FDA has concluded its investigation of an outbreak of Salmonella Miami with a one-word public statement: closed.

A source for the pathogen, which has sickened at least 64 people, remains unknown, according to the Food and Drug Administration. In its weekly outbreak update, the agency ended the investigation with as little fanfare as it began it. The FDA’s initial announcement was a one-line entry on its weekly outbreak update table.

As of yesterday, the Centers for Disease Control and Prevention had not posted any information about the outbreak. The CDC did not respond to a request for comment on April 14, the day of the FDA announcement. 

UK – Sainsbury’s Campylobacter rates in chicken hit FSA threshold

Food Safety News

Campylobacter kswfoodworld

Sainsbury’s has recorded the worst Campylobacter in chicken results for the final three months of 2020 closely followed by Tesco.

Figures come from the top nine retailers in the United Kingdom publishing the latest quarter of testing findings.

The Food Standards Agency (FSA) threshold is 7 percent of birds with more than 1,000 colony forming units per gram (CFU/g) of Campylobacter.

Sainsbury’s reported 7 percent of chickens sampled were above 1,000 CFU/g in the fourth quarter of 2020 (4Q), compared to 2 percent in 3Q, slightly more than 4 percent in 2Q and about 3 percent in 1Q 2020.

Research – What lives inside the chicken gut?

Phys Org

In a recently published study, investigators from Norwich and Surrey have more than doubled the number of microbial species known to live in the chicken gut. As the health and wealth of humans is tied to the health and productivity of chickens, this lays down a key resource for all future studies on the gut microbiome of this important food animal.

With three times as many chickens as people on our planet, this ubiquitous food animal underpins human nutrition and health across the globe—whether through subsistence farming or intensive production, chickens supply more of our food than any other animal. Chicken meat is surging in popularity as a lower-carbon alternative to meat from other livestock, whilst eggs remain an important and affordable source of nutrition worldwide. However, poultry are also a source of antimicrobial resistance and of pathogens such as Campylobacter, Salmonella and E. coli that threaten human health.

Research – Bacterial Spore Inactivation in Orange Juice and Orange Peel by Ultraviolet-C Light


Spore-forming bacteria are a great concern for fruit juice processors as they can resist the thermal pasteurization and the high hydrostatic pressure treatments that fruit juices receive during their processing, thus reducing their microbiological quality and safety. In this context, our objective was to evaluate the efficacy of Ultraviolet-C (UV-C) light at 254 nm on reducing bacterial spores of Alicyclobacillus acidoterrestrisBacillus coagulans and Bacillus cereus at two stages of orange juice production. To simulate fruit disinfection before processing, the orange peel was artificially inoculated with each of the bacterial spores and submitted to UV-C light (97.8–100.1 W/m2) with treatment times between 3 s and 10 min. The obtained product, the orange juice, was also tested by exposing the artificially inoculated juice to UV-C light (100.9–107.9 W/m2) between 5 and 60 min. A three-minute treatment (18.0 kJ/m2) reduced spore numbers on orange peel around 2 log units, while more than 45 min (278.8 kJ/m2) were needed to achieve the same reduction in orange juice for all evaluated bacterial spores. As raw fruits are the main source of bacterial spores in fruit juices, reducing bacterial spores on fruit peels could help fruit juice processors to enhance the microbiological quality and safety of fruit juices. View Full-Text

Research – Effect of the Dry-Cured Fermented Sausage “Salchichón” Processing with a Selected Lactobacillus sakei in Listeria monocytogenes and Microbial Population


In the present work, the effect of processing of dry-cured fermented sausage “salchichón” spiked with the selected Lactobacillus sakei 205 was challenge-tested with low and high levels of L. monocytogenes. The evolution of the natural microbial population throughout the “salchichón” ripening was also evaluated. For this, a total of 150 “salchichón” were elaborated and divided into six equal cases which were inoculated with different levels of L. monocytogenes, and L. sakei 205. Afterwards, sausages were ripened for 90 days according to a typical industrial process. Moisture content (%) and water activity (aw) decreased throughout the ripening up to values around 26% and 0.78, respectively. No differences for moisture content, aw, pH, NaCl and nitrite concentration were observed between the analyzed cases. Lactic acid bacteria counts in the L. sakei 205 inoculated cases were always higher than 6 log CFU g−1 during ripening. Enterobacteriaceae counts were reduced during ripening until non-detectable levels at the end of processing. Reductions in L. monocytogenes counts ranged from 1.6 to 2.2 log CFU g−1; therefore, the processing of “salchichón” itself did not allow the growth of this pathogen. Reduction in L. monocytogenes was significantly higher in the cases inoculated with L. sakei 205. View Full-Text

USA – Investigation Details – Multistate outbreak of Salmonella Hadar infections linked to raw ground turkey


Epidemiologic Data

As of April 12, 2021, 28 people infected with the outbreak strain of Salmonella Hadar have been reported from 12 states (see map). Illnesses started on dates ranging from December 28, 2020, to March 4, 2021 (see timeline).

Sick people range in age from less than 1 to 92 years, with a median age of 49, and 68% are female. Of 19 people with information available, 2 have been hospitalized. No deaths have been reported.

The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 2 to 4 weeks to determine if a sick person is part of an outbreak.

State and local public health officials are interviewing people about the foods they ate in the week before they got sick. Of the 10 people interviewed, 6 (60%) reported eating ground turkey. This percentage was significantly higher than results from a survey of healthy people in which 13% of respondents reported eating ground turkey in the week before they were interviewed. This suggests that people in this outbreak got sick from eating ground turkey.

UK – Sainsbury’s recalls Taste the Difference Medjool Dates because of possible contamination with Hepatitis A


Sainsbury’s is taking the precautionary action of recalling Taste the Difference Medjool dates because they might be contaminated with Hepatitis A.

Product details

Taste the Difference Medjool dates
Pack size 200g and 500g
Best before All dates

Risk statement

These products might be contaminated with Hepatitis A. Symptoms caused by Hepatitis A usually include fever, nausea, abdominal cramps, diarrhoea, dark-coloured urine and jaundice (a yellowing of the skin).

Action taken by the company

Sainsbury’s is recalling the above products. Point of sale notices will be displayed in all retail stores that are selling these products. These notices explain to customers why the products are being recalled and tell them what to do if they have bought the product. Please see the attached notice.

Our advice to consumers

If you have bought these products do not eat them. Instead, return them to the store from where they were bought for a full refund.

Research – Evaluation of ceftazidime as an antibiotic supplement of mannitol-yolk-polymyxin B agar used for the enumeration of Bacillus cereus in ready-to-eat vegetables

Journal of Food Protection


Bacillus cereus, which causes foodborne disease, is detected using selective media. However, competing flora is the most common factor preventing the correct enumeration of B. cereus on selective agars. In this study, we aimed to improve the selectivity of mannitol-yolk-polymyxin B agar (MYPA) and its modified version containing trimethoprim (mMYPA) developed in our previous study by supplementation with ceftazidime (16 μg/mL). Ceftazidime-supplemented MYPA (C-MYPA16) and mMYPA (C-mMYPA16) were evaluated for bacteria recoverability and selectivity using three types of ready-to-eat vegetables. Four B. cereus and one B. thuringiensis strains were mixed and artificially inoculated into vegetable salad, radish sprouts, and sprout mix, and then recovered using MYPA, mMYPA, C-MYPA16, and C-mMYPA16. In all tested vegetables, mMYPA, C-MYPA16, and C-mMYPA16 exhibited similar recoverability of B. cereus / thuringiensis ( p > 0.05), whereas MYPA showed undistinguishable colonies in case of radish sprouts and sprout mix. At the same time, C-mMYPA16 provided the best selectivity compared with the other agars because it eliminated most of competing flora in the tested vegetables, especially in sprouts, without negatively affecting the recovery of B. cereus / thuringiensis . Our results indicate that the supplementation of mMYPA with ceftazidime may improve medium selectivity for B. cereus / thuringiensis in food testing.

Research – Climate change emerges as another culprit in leafy green food poisoning outbreaks

The Counter

The last decade has been particularly rough on the leafy greens industry. If you’ve followed lettuce news, you’re certainly aware of the multiple outbreaks of foodborne pathogens like E. coli, which have killed hundreds and sickened thousands more. Cattle feedlots have emerged as a major source of contamination for leafy green contamination but over at Eater, Jenny Zhang homes in on another culprit: climate change. Though it’s an emergent field of study and many unknowns remain, some early observations include: Rising temperatures can help E. coli and salmonella proliferate; those same hot temps provoke cattle into shedding pathogens more readily; and climate change-related flooding can rapidly spread contamination into water supplies used in irrigation. “Think of climate change as both an amplification of existing hazards, as well as a potential trigger for things we can’t foresee,” writes Zhang.