Category Archives: Bacteria

Research – Microbiological profile, incidence and behavior of Salmonella on seeds traded in Mexican markets.

Journal of Food Protection

Seed consumption has increased in recent years because the high nutrient content of seeds. However, the number of outbreaks caused by Salmonella associated with the consumption of low water activity food items has also increased, although these food items do not support microbial growth. The main goal of this study was to quantify microbial indicators and to determine the prevalence and content of Salmonella spp. in chia, amaranth and sesame seeds obtained from Mexican retail outlets. In addition, the behavior of this pathogen on seeds was also evaluated. One hundred samples of each product (chia, amaranth and sesame seeds) were collected from Queretaro City markets. Aerobic plate count (APC), coliforms and Escherichia coli were quantified, and the presence and number of Salmonella were also determined. Chia, amaranth and sesame seeds (1 kg each) were inoculated with a cocktail containing five Salmonella strains (~6 log CFU mL -1 ) and were stored at ambient temperature and populations of Salmonella were quantified. The median APC contents in chia, amaranth, and sesame seeds were 2.1, 2.4, and 3.8 log CFU g -1 , respectively, and the content of coliforms on the seeds ranged from 0.48 to 0.56 log MPN g -1 . E. coli was present at low concentrations in the three types of seeds. Salmonella was detected in chia (31%), amaranth (15%), and sesame (12%) seeds, and the population ranged from 0.48 to 0.56 Log MPN g -1 . Salmonella spp. decreased through 240 days of storage, showing inactivation rates of 0.017, 0.011 and 0.016 log CFU h -1 in chia, amaranth, and sesame seeds, respectively. The high prevalence of Salmonella in the seeds highlights potential risks for consumers, particularly giving that seeds are generally consumed without treatments guaranteeing pathogen inactivation.

Research – Evaluation of Hot-air Drying to Inactivate Salmonella spp. and Enterococcus faecium on Apple Pieces

Journal of Food Protection

Hot-air drying processes are used to provide specific quality attributes to products, such as dehydrated apple pieces. To comply with the U. S. Food and Drug Administration Food Safety Modernization Act, there is a need to understand microbial lethality during these processes. The objective of this study was to determine the level of inactivation provided by hot-air drying on a Salmonella cocktail inoculated onto apple cubes and to evaluate the performance of Enterococcus faecium as a surrogate. A Salmonella cocktail ( S. Agona, S. Tennessee, S. Montevideo, S. Mbandaka and S. Reading) and E. faecium were individually inoculated onto cored, peeled Gala apple cubes at 9.2 ± 0.3 and 8.8 ± 0.1 log CFU/sample, respectively . Apple cubes were dried at 104°C or 135°C in ~1.5 kg batches using a hot-air dryer with a vertically directed heat source and without mixing. Three subsamples, consisting of 4 inoculated cubes, were enumerated at each time point (n ≥ 5) from multiple product bed depths. Water activity decreased throughout the duration of the study with samples at 135°C drying faster than 104°C. Samples at the bottom bed depth, closer to the heat source, dried faster than those at the higher bed depth, regardless of temperature. Significant microbial inactivation was not seen immediately. It took >10 min at the bottom bed depth or > 40 min of drying at the top bed depth, regardless of temperature (p < 0.05).  By the end of drying average Salmonella inactivation of greater than 5 log CFU/sample was achieved. At temperature conditions evaluated, E. faecium inactivation was slower than Salmonella , indicating that it would likely serve as a good surrogate for in-plant validation studies. Case hardening did not inhibit microbial inactivation in the conditions tested. Hot-air drying under the conditions evaluated may provide a preventive control in the production of dehydrated products, such as apples.

Research – The growth characteristics of Bacillus cereus in sake and during its manufacture.

Journal of Food Protection

Sake (Japanese rice wine) has been recognized as being low-risk in terms of its microbiological safety. However, a confirmation of the food safety aspects of sake based on scientific evidence is important for establishing consumer confidence, in part because consumer concerns regarding food safety have increased. The presence of Bacillus cereus spores in refined rice wine has been reported, and in light of consumers’ growing concern over food safety, the establishment of food and beverage safety is important for consumers’ reassurance. Herein, to confirm the microbiological safety of sake, we investigated the content and growth of B. cereus. We conducted a spore addition test to determine whether B. cereus spores grow during sake production, and we observed no growth or germination of B. cereus spores during the manufacturing process. We also observed that processes such as solid-liquid separation and filtration help remove the risk posed by B. cereus. We then conducted a survey to assess the density of B. cereus in various commercial sake products. We analyzed 162 samples of commercial sake and observed that 11 of the products had ≥1 CFU of living cells in 1 mL of sake (detection rate: 6.8%). There was no product in which ≥100 CFU/mL-sake of living cells was detected. Our findings confirmed that the density of these bacteria in sake is lower than that in other foods, and the probability of infection is very low. The emetic toxin produced by B. cereus was not detected in any of the sake samples. This is the first study based on experimental data demonstrating that B. cereus is not able to grow in sake or during the sake manufacturing process. We thus conclude that the safety risk of B. cereus in sake is negligible. Our findings indicate that Bacillus cereus is not a significant hazard in the sake brewing process, and they will contribute to the food hygiene management based on scientific evidence in sake breweries.

Research – Antimicrobial and preservative effects of the combinations of nisin, tea polyphenols, rosemary extract and chitosan on pasteurized chicken sausage

Journal of Food Protection

The study evaluated the antimicrobial and antioxidant effects of the combinations of nisin (NS), tea polyphenols (TP), rosemary extract (RE) and chitosan (CS) on low-temperature chicken sausage. An orthogonal test revealed that the most effective antimicrobial compositions were equal-quantity mixtures of 0.05% NS + 0.05% TP + 0.03% RE + 0.55% CS . The mixture also produced strong antimicrobial and antioxidant effects in low-temperature chicken sausage related to extend the shelf life to more than 30 days at 4°C. The study also investigated the inhibitory zone of NS, TP, RE and CS against Pseudomonas aeruginosa , lactic acid bacteria (LAB) and Staphylococcus aureus which were the dominant spoilage bacteria in low-temperature chicken sausage. NS had the greatest inhibitory effect on LAB and Staphylococcus aureus , exhibiting clear zone diameters of 19.7 mm and 17.8 mm respectively. TP had the largest inhibitory effect on Pseudomonas aeruginosa , exhibiting a clear zone diameter of 18.2 mm. These results indicated that the combination of NS, TP, RE and CS could be used as natural preservative s to efficiently inhibit the growth of spoilage microorganisms in low-temperature chicken sausage so as to improve its safety and shelf life.

Research – The effect of feeding a Saccharomyces cerevisiae fermentation derived postbiotic as a pre-harvest food safety hurdle for reducing Salmonella Enteritidis in the ceca of layer pullets

Journal of Food Protection

Salmonella Enteritidis is responsible for a significant proportion of foodborne Salmonellosis in the United States and continues to be attributable to table eggs, despite increased federal oversight in recent years. Technologies, including feed additives, continue to be evaluated for pre-harvest application of their potential food safety benefits. Here, Diamond V Original XPC™, a Saccharomyces cerevisiae fermentation based postbiotic (SCFP), was evaluated for its effectiveness in the reduction of Salmonella Enteritidis (SE) colonization in young layer pullets. A total of forty, day-old Hy-Line W-36 layer pullets were equally divided and randomly assigned to one of two dietary treatments with SCFP, or without (PCON) and orally gavaged on Day 28 with 10 6 CFU/mL of SE. Another twenty, day-old layer pullets were fed the same control feed without SCFP and blank inoculated on Day 28 with 1 ml of sterile PBS to serve as a negative control (NCON). Qualitative and quantitative analyses of cecal Salmonella contents were performed for all birds on Day 32. The prevalence of SE in the ceca of all directly challenged birds was 100%, however, the SE concentration in birds fed SCFP diet (3.35 Log 10 CFU/g) was significantly lower ( P <0.0001) than that of the PCON birds not fed SCFP (4.49 Log 10 CFU/g). Moreover, the proportion of SE colonized individuals with enumerable SE concentrations was lower in SCFP fed birds (57.9%) when compared to the PCON (95.0%). These data suggest that inclusion of SCFP in the diet may aid in the reduction of SE within the ceca of commercial laying hens and could serve as an additional, pre-harvest food safety hurdle.

Research – A comparison of Salmonella survival and detection using an enrichment technique in dry and wet inoculated rendered chicken fat treated with sodium bisulfate

Journal of Food Protection

The differences in the recovery of Salmonella from rendered chicken fat treated with sodium bisulfate (SBS) when inoculated with a dry vs wet inoculum was evaluated. Food grade rendered chicken fat was inoculated with a dry and wet inoculum containing a Salmonella cocktail (S. Enteritidis, S. Heidelberg, and S. Typhimurium). In addition, the effect of an antimicrobial treatment (sodium bisulfate, SBS) against Salmonella spp. in both the aqueous and fat phase of the chicken fat was evaluated. The untreated control samples in the aqueous phase had a consistent level of Salmonella (~7 log) when both the dry and wet inoculum was used. In the SBS treated aqueous phase, Salmonella were not detectable after 6h when the wet inoculum was used; whereas, when using the dry inoculum, the Salmonella were not detectable at 24h. Salmonella were detected for up to 6h in the SBS treated fat phase when the dry inoculum was used as compared to 2h with the wet-inoculum. The 24h fat samples which failed to show growth on trypticase soy agar were enriched for Salmonella isolation followed by confirmation by polymerase chain reaction using primers for the invA gene. Both SBS treated and control samples from the dry inoculated, and the inoculated control from the wet inoculated rendered chicken fat tested positive for Salmonella. However, the SBS treated sample from the wet inoculated fat was negative for Salmonella. The use of dry SBS powder against dry Salmonella inoculum in the fat matrix caused only ~2.8 log reduction after 24h as compared to ~2.2 log reduction in the positive control. However, the recovery of Salmonella from untreated control fat was lower and was not different (P ≤ 0.05) than the SBS treated fat. The results suggest the development of potential VBNC states of Salmonella or the presence of injured cells in rendered chicken fat hence suggesting that testing should include an enrichment and appropriate molecular confirmation instead of agar plating alone

Netherlands – Important safety warning AH burgers, bratwurst and beef finches – STEC E.coli

NVWA

Albert Heijn warns against a number of beef products with an expiry date of 24 or 25 September 2020. The E.coli bacteria was found in the products.

It concerns the following products:

  • AH mini hamburger 10 pieces, TGT 24-09-2020
  • AH hamburger 8 pieces, use-by-date 9/24/2020 and 9/25/2020
  • AH beef bratwurst 4 pieces, TGT 24-09-2020
  • AH hamburger 2 pieces, TGT 25-09-2020
  • AH hamburger 4 pieces, TGT 25-09-2020
  • AH beef finch 2 pieces, TGT 25-09-2020

The beef products are no longer in Albert Heijn stores, but customers can have these products in the freezer. Albert Heijn asks customers not to eat the beef products and to return them to an Albert Heijn store where they will be reimbursed for the purchase price upon return.

See also the Albert Heijn website

Download ‘Important safety warning for AH burgers, bratwurst and beef finches’

PDF document | 1 page | 166 KB

Warning | 05-10-2020

E.coli

Eating a product with an E.coli bacteria (faeces bacteria, STEC, EHEC) can, if not thoroughly cooked, cause nausea, vomiting and (bloody) diarrhea within a week. Especially for young children, the elderly, people with low immunity and pregnant women. Consult your doctor or general practitioner for more information if you have health complaints after eating the said product.

6 packs of Albert Heijn beef products

Research – Recovery Rate of Cells of the Seven Regulated Serogroups of Shiga Toxin-Producing Escherichia coli from Raw Veal Cutlets, Ground Veal, and Ground Beef from Retail Stores in the Mid-Atlantic Region of the United States

Journal of Food Protection

A total of 482 veal cutlet, 555 ground veal, and 540 ground beef samples were purchased from retail establishments in the Mid-Atlantic region of the U.S. over a non-contiguous, two-year period between 2014 and 2017. Samples (325 g each) were individually enriched and screened via real-time PCR for all seven regulated serogroups of Shiga toxin-producing Escherichia coli (STEC). Presumptive STEC positive samples were subjected to serogroup-specific immunomagnetic separation and plated onto selective media. Up to five isolates typical for STEC from each sample were analyzed via multiplex PCR for both the virulence genes (i.e., eae , stx 1 and/or stx 2 , and ehxA ) and serogroup-specific gene(s) for the seven regulated STEC serogroups. The recovery rates of non-O157 STEC from veal cutlets (3.94%, 19 of 482 samples) and ground veal (7.03%, 39 of 555 samples) were significantly higher (P < 0.05) than that from ground beef (0.93%, 5 of 540 samples). In contrast, only a single isolate of STEC O157:H7 was recovered; this isolate originated from one (0.18%) of 555 samples of ground veal. Recovery rates for STEC were not associated with state, season, packaging type, or store type (P > 0.05), but were associated with brand and fat content (P < 0.05). Pulsed-field subtyping of the 270 viable/confirmed STEC isolates from the 64 total samples testing positive revealed 78 pulsotypes (50 to 80% similarity) belonging to 39 pulsogroups, with ≥90% similarity among pulsotypes within pulsogroups. Also, multiple isolates from the same sample displayed an indistinguishable pulsotype for 43 of 64 (67.7%) samples testing positive.  These findings support related data from regulatory sampling exercises over the past decade and confirm that recovery rates for the regulated STEC serogroups are appreciably higher for raw veal compared to raw beef samples as was also observed herein for meat purchased at food retailers in the Mid-Atlantic region of the U.S.

Research – Thermal Resistance of Single Strains of Shiga Toxin-Producing Escherichia coli O121:H19 and O157:H7 Based on Culture Preparation Method and Osmolyte-Reduced Water Activity

Journal of Food Protection

Pathogen thermal resistance studies on low-water activity foods (LWAF) use a variety of methods to inoculate food, as well as strategies to reduce water activity, which can influence thermal resistance observations. This study investigated effects of culture preparation method and osmolyte-induced water activity on thermal resistance of two Shiga toxin-producing Escherichia coli (STEC; O121:H19, O157:H7) challenged with isothermal conditions, determining D – and z -values for each isolate (56, 59, and 62 ° C). Tryptic Soy Broth (TSB) and Agar (lawn cultures) were compared. D -values of broth cultures were significantly and consistently larger than those of lawn cultures, and O121 was significantly more resistant than O157, but only at 56 ° C ( p < 0.05). To compare potential effects of water activity on STEC thermal resistance, cells were suspended in osmolyte solutions with varying water activity: high (TSB, a w 0.99), intermediate (61% glycerol or 26% NaCl, a w 0.75), and low (82% glycerol, a w 0.5). In most instances, STEC in high-water activity broth exhibited greater heat resistance compared to reduced-water activity solutions, except the glycerol intermediate-water activity solution (a w 0.75). Magnitudes varied with strain and temperature. The z -values of lawn cultures were significantly lower than those of broth cultures ( p < 0.05), but there were only some differences between high-a w and reduced-a w samples. There were no significant differences of z -values based on strain type. These results highlight that thermal resistance can be affected by culture preparation and that osmolyte-induced changes to water activity influence thermal inactivation of STEC by varying magnitudes. These results emphasize the challenges between extrapolating results from lab inactivation kinetic experiments to determine the inactivation of low water activity foods, especially those considered dry in nature.

Belgium – Sequoia – Organic free-range chicken thighs from Le Picoreur. – Salmonella

AFSCA

In agreement with the AFSCA, Sequoia is withdrawing from sale the product Le Picoreur organic free-range chicken thighs and is recalling it to consumers because of the presence of Salmonella.

Sequoia asks its customers not to consume this product and to return it to the point of sale where it was purchased, with proof of purchase for reimbursement.

Product description
– Product name: BLC organic free-range chicken thigh
– Brand: Le picoreur
– Use-by date (DLC) (“To be consumed until”) and batch number:
         – 27, 28 and 30/09 / 20 with batch number 25801101
– 5/10/2020 with batch number 26501501 (update)
– Health stamp: FR 85.223.001 CE
– Sale period: from 09/15/20 to 09/29/20
– Type of packaging: plastic

The product was sold via:
Sequoia Stockel – 101, rue de l’Eglise, 1150 Woluwe-Saint-Pierre
Sequoia Jourdan – 2, rue Gray, 1040 Etterbeek

For any further information , contact:
Sequoia
info@sequoia.bio