Category Archives: Food Technology

New Zealand – Shellfish biotoxin alert extended for North Island west coast, including Raglan

MPI

The Ministry for Primary Industries today extended the current public health warning against collecting shellfish from the west coast of the North Island. The warning now extends from South Head (Manukau Harbour entrance) to Tirua Point (south of Kawhia Harbour).

Paralytic Shellfish Poisoning (PSP) toxins have been detected in shellfish from the Kawhia Harbour above the safe limit set by MPI.

The other public health warning for Hawke’s Bay remains in place.

Mussels, oysters, tuatua, pipi, toheroa, cockles, scallops, catseyes, kina (sea urchin) and all other bivalve shellfish should not be eaten.

Note, cooking shellfish does not remove the toxin.

Pāua, crab and crayfish may still be eaten if the gut has been completely removed prior to cooking, as toxins accumulate in the gut. If the gut is not removed its contents could contaminate the meat during the cooking process.

Symptoms typically appear between 10 minutes and 3 hours after ingestion and may include:

  • numbness and a tingling (prickly feeling) around the mouth, face, and extremities (hands and feet)
  • difficulty swallowing or breathing
  • dizziness
  • headache
  • nausea
  • vomiting
  • diarrhoea
  • paralysis and respiratory failure and in severe cases, death.

If anyone becomes ill after eating shellfish from an area where a public health warning has been issued, phone Healthline for advice on 0800 61 11 16, or seek medical attention immediately. You are also advised to contact your nearest public health unit and keep any leftover shellfish in case it can be tested.

Monitoring of toxin levels will continue and any changes will be communicated accordingly. Commercially harvested shellfish – sold in shops and supermarkets, or exported – is subject to strict water and flesh monitoring programmes by MPI to ensure they are safe to eat.

Switzerland – Cheese firm in Switzerland investigated over Listeria link

Cheese firm in Switzerland investigated over Listeria link

USA – U.S. among countries sent Brazil nuts contaminated with Salmonella

U.S. among countries sent Brazil nuts contaminated with Salmonella

Research -Erythrosine B (Red Dye No. 3): A potential photosensitizer for the photodynamic inactivation of foodborne pathogens in tomato juice

Wiley Online

The objectives of this study were to evaluate the efficacy of erythrosine B (ERY, Red No. 3)‐mediated photodynamic therapy (PDT) for inactivating Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in tomato juice. The inoculated tomato juice was subjected to xenon light (E − L+), ERY (E + L−), or xenon light and ERY combination (E + L+) treatments. Treatment with E + L+ for 15 min decreased the cell counts of E. coli O157:H7, . Typhimurium, and L. monocytogenes by 6.77, 2.74, and 6.43 log CFU/mL, respectively, without generating sublethally injured cells. The cell count reductions of E. coli O157:H7 and L. monocytogenes in the E + L+ treatment group were higher than the sum of cell count reductions in the E − L+ and E + L− treatment groups, which indicated the synergistic activity of the treatment combination. The 3d and 5d values calculated by the Weibull model indicated that . Typhimurium exhibited higher resistance to the E + L+ treatment than the other two pathogens. Compared with control group, the E + L+ treatment group exhibited higher lycopene content and * (red) value, whereas the pH value and sensory attributes were not significantly ( > .05) altered. These results suggest that ERY‐mediated PDT can be potentially applied to control foodborne pathogens in tomato juice products without negatively affecting the product quality.

Research – Enhanced elimination of Salmonella Typhimurium and Campylobacter jejuni on chicken skin by sequential exposure to ultrasound and peroxyacetic acid

Wiley Online

The present study investigated the effects of combined ultrasound (37 kHz, 380 W for 5 min) and peroxyacetic acid (PAA; 50–200 ppm) treatment on the reduction of Salmonella Typhimurium and Campylobacter jejuni on chicken skin. Ultrasound was not sufficient to inactivate . Typhimurium (0.48 log CFU/g reduction) or C. jejuni (0.25 log CFU/g reduction), whereas PAA significantly ( < .05) reduced . Typhimurium (0.93–1.59 log CFU/g reduction) and C. jejuni (0.77–1.52 log CFU/g reduction). However, maximum reductions of 2.21 and 2.08 log CFU/g were observed for . Typhimurium and C. jejuni , respectively, for combined treatment with 5 min of ultrasound and 200 ppm PAA. Our results indicate that a combination of ultrasound treatment for 5 min and 200 ppm PAA was more effective in reducing . Typhimurium and C. jejuni compared to the individual treatments, without significantly affecting the color or texture of the chicken skin, thus, demonstrating its potential to increase the microbial safety during poultry processing.

Research – Viability of Listeria monocytogenes and Salmonella Typhimurium after isochoric freezing

Wiley Online

Isochoric freezing, different from isobaric (conventional) freezing, allows for storage below freezing temperatures without significant damage from ice formation. While several types of tissues have been successfully stored in sub‐zero isochoric conditions, it is unknown how isochoric freezing affects pathogenic microorganisms. Thus, the objective of this study was to investigate the survival of Salmonella Typhimurium and Listeria monocytogenes at below freezing storage (<0°C) in isochoric conditions. Tested conditions included storage at −4, −7, and −15°C for 24 hr and at −15°C for 1, 2, 3, 6, 12, and 24 hr. A comparison of bacterial survival during isobaric freezing was included with every trial. Additionally, bacterial cells were examined for morphological damage using transmission electron and field‐emission scanning electron microscopes. Isochoric freezing at −15°C for 24 hr reduced both species of bacteria down to unrecoverable levels and maximum efficacy achieved after the 6 hr timepoint for L. monocytogenes and the 12 hr timepoint for S. Typhimurium. When viewed using electron microscopy, S. Typhimurium cells were noticeably disfigured with regions of cytosol separated from the cell wall. The results of this study demonstrate that isochoric freezing is capable of substantial levels of pathogen reduction. Unlike conventional nonthermal interventions, isochoric freezing does not require additional devices such as elevated pressure machines or pulsed electric fields and can be achieved with simple, inexpensive, rigid closed volume containers such as household freezers or commercial cold storage facilities.

Research – Incidence of aflatoxins, ochratoxin A, zearalenone, and deoxynivalenol in food commodities from Turkey

Wiley Online

AspergillusPenicilliumFusarium, and Alternaria species which produce toxic metabolites, create a big problem in terms of the production of reliable human food and animal feeds. This study was conducted to determine the mycotoxin contents of foodstuff collected uniformly in each year of 2017, 2018, and 2019 in Şebinkarahisar, Turkey by enzyme‐linked immunosorbent assay. The highest total aflatoxin, and aflatoxin B1 were determined in red pepper in 2018 with 6.47 ± 0.07 and 4.58 ± 0.01 μg kg−1, respectively while the highest ochratoxin amount was obtained again in the red paper in 2019 with 7.97 ± 0.57 μg kg−1. Contrarily, the highest incidence of zearalenone and deoxynivalenol was determined in wheat and corn flour with 12.49 ± 0.3 and 397.6 ± 7.34 μg kg−1, respectively. Weather changes have also been found to affect the incidence of mycotoxin. But, determined mycotoxin values do not pose a risk according to the Turkish Food Codex Contaminants Regulation.

Research – Variation of antibiotic resistance in Salmonella Enteritidis, Escherichia coli O157 :H7 , and Listeria monocytogenes after exposure to acid, salt, and cold stress

Wiley Online

Abstract

Bacteria with antibiotic‐resistant could seriously threaten to human health, increasing the treatment cost for infections and negatively affecting treatment outcomes. Stress adaptation is one possible mechanism for the acquisition or enhancement of antibiotic resistance in bacteria as a result of cross‐protection. In this study, the effects of acid, salt, and cold stress on the antibiotic resistance of Salmonella Enteritidis, Listeria monocytogenes , and Escherichia coli O157:H7 were investigated using the disc diffusion method. For S. Enteritidis, acidic growth conditions increased resistance to ciprofloxacin and erythromycin ( < .05), and addition of 4% NaCl to growth media decreased resistance to chloramphenicol ( < .05). Irrespective of pH and the NaCl concentration of the growth medium, refrigerated E. coli O157:H7 showed increased resistance to amoxycillin, ciprofloxacin, gentamicin, streptomycin, and erythromycin ( < .05). Acid‐adapted L. monocytogenes showed decreased the resistance to amoxycillin, ampicillin, chloramphenicol, ciprofloxacin, erythromycin, gentamicin, streptomycin, and tetracycline ( < .05). In conclusion, prolonged exposure of foodborne pathogens to acid, salt, and cold stress alters their antibiotic resistance. However, the effect of acid, salt, and cold stress on bacterial antibiotic resistance depend on both the bacterial species and the specific antibiotic. Therefore, multiple factors need to be considered for a foodborne antimicrobial resistant risk assessment.

Research – The effect of royal jelly and propolis alone and in combination on inhibition of Aspergillus parasiticus growth, aflatoxin production, and aflR gene expression

Wiley Online

The objective of this study was to determine the inhibitory effect of royal jelly (RJ) and propolis on growth, aflatoxin production and aflR gene expression in Aspergillus parasiticus . Inhibitory effect of RJ and propolis against a standard strain of A. parasiticus (ATCC 15517) was determined alone and in combination in accordance with the CLSI M38‐A2 and checkerboard methods, respectively. The aflatoxin concentrations in the control and treated media were determined by HPLC. Also, the quantitative changes in the aflR gene expression were analyzed. The minimum inhibitory concentrations (MIC) of RJ and propolis alone were 3,200 and 100μg/ml, respectively. Also, the MICs of RJ and propolis in combination were 200 and 25μg/ml, respectively. When combined, a synergistic interaction was observed with a FICI of 0.312. Total levels of aflatoxin decreased from 386.1ppm to 8.72, 3.01 and 1.75ppm at 1,600μg/ml of RJ, 50μg/ml of propolis and 100+12.5μg/ml of RJ and propolis, respectively. In addition, the level of afIR gene expression was significantly decreased after treatment with RJ and propolis extracts alone and with their combination. The findings reveal that RJ and propolis extracts, either alone or in combination, have a significant inhibitory effect on aflR gene expression in aflatoxin production.

UK – Outbreak investigation finds different Salmonella strain in chicken nuggets

Outbreak investigation finds different Salmonella strain in chicken nuggets