Salmonella prevalence and total microbial and spore populations in spices imported to Japan

Physical, chemical, sorption and microbiological characteristics of fennel fruits

Fennel (Foeniculum officinale Mill. var. dulce Mill) is an annual aromatic plant of the Lamiaceae family. Its fruits are processed to obtain essential oil for use in the food industry and cosmetics. The physical parameters of the fruits, i.e. length (5.50-8.00 mm), width (1.50-2.00 mm), volume of 100 fruits (1.36 × 10-6 m3), density of 100 fruits (935.82 kg/m3), average volume of one fruit (1.36 × 10-8 m3), average equivalent diameter of one fruit (2.96 mm), angle of repose, stainless steel (from 16 to 22°), angle of repose, black steel (from 19 to 28°), angle of repose, plywood (from 18 to 24°), and their chemical parameters, i.e. moisture (13.49%), ash (6.49%), protein (18.25%), essential oil (8.38%), vegetable oil (10.52%), and total carbohydrates (51.04%) were determined for the fruits. The adsorption and desorption isotherms of the fennel fruits were obtained using the static gravimetric method at two temperatures, 20 and 40 °C. The Halsey model provided a good description of the sorption isotherms, which were of type II according to Brunauer's classification. The increase in the temperature led to a significant decrease in the monolayer moisture. The contamination on the fruit surface at three relative humidities (0.43, 0.59, and 0.76) at 20 °C was determined.

How can packaging, source and food safety management system affect the microbiological quality of spices and dried herbs? The case of a developing country

Spices and herbs are widely used in almost all types of food preparation and their microbial contamination may cause spoilage and pose public health risk. Thus, the aim of this study was to assess the effect of packaging, source and a food safety management system (FSMS) on the microbiological quality of spices and dried herbs in a developing country, like Lebanon. For this, a total of 96 composite samples of thirteen most commonly consumed types of spices and dried herbs were collected twice at three-month interval. Each type was purchased in 5 common brands from 4 categories: packaged in companies with FSMS, packaged in companies without FSMS, packaged imported, and unpackaged. Total aerobic mesophilic bacteria (TAMB), sulfite reducing anaerobic bacteria, C. perfringens, coliforms, E. coli, yeasts and molds were found in 89%, 43%, 18%, 15%, 1% and 54% of the samples, respectively. All samples were negative for Salmonella. One per cent, 4%, 6%, 1% and 7% of the samples had unacceptable levels of TAMB, coliforms, sulfite reducing anaerobic bacteria, E. coli, yeasts and molds, respectively. Among the four categories, imported samples had the lowest microbiological load, followed by locally packaged in companies with FSMS, then locally packaged in companies without FSMS and the highest microbiological load was for the unpackaged spices and dried herbs. This study highlighted the importance of storage conditions, good hygienic practices, process controls and FSMSs in the spices and dried herbs sector.

Evaluation of thermal inactivation parameters of Salmonella in whole wheat multigrain bread

This study was conducted to validate a simulated commercial whole wheat multigrain bread baking process at 375 °F (190.6 °C) oven temperature for 35 min to inactivate Salmonella, and to determine the thermal inactivation parameters of a 7-serovar Salmonella cocktail in whole wheat multigrain bread dough. A ≥5-log CFU/g reduction in Salmonella population was achieved by 15 min, and no viable Salmonella was detected after enrichment plating by 16 min. The a_w of the bread crumb (0.96) after baking and 60 min of cooling was similar to that of pre-baked bread dough, whereas the a_w of bread crust decreased to 0.81 at the end of baking and cooling. The D-values of the Salmonella cocktail in bread dough were 59.6, 20.0 and 9.7 min at 50, 52 and 55 °C, respectively; and the z-value was 6.5 °C.

Microbial Evaluation of Spices in Ethiopia

Introduction:

Since spices are taken as ready-to-eat products, they are not subjected to heat treatment. The use of spices contaminated with pathogens can lead to morbidity and mortality.

Materials and Methods:

The study was conducted on 162 samples of 25 spices collected from retail and production sites in different regions of Ethiopia between January 2010 to December 2017 to determine the concentrations of heterotrophic plate count and Staphylococcus aureus by pour plate method; for coliforms using NMKL Method No. 44; for mould and yeast enumeration using spread method and for Salmonella using ES ISO 6579. The data was analysed using SPSS version 20.0.

Results:

Moulds, yeasts, total coliforms, heterotrophic plate count, total coliforms, thermotolerant coliforms, E. coli and S. aureus above the acceptable limits were observed in 5 (3%), 7 (4.3%), 2 (1.2%), 20 (12.3%), 10 (6.2%), 9 (5.6%) and 19 (11.7%) samples respectively. Salmonella species was not noticed in any of the samples tested. No bacterial and fungal contaminations were observed in 11 of 25 spices.

Conclusions:

Few spices samples had 1.2 to 12.3% of the microbiological indicators, spoilages or pathogens exceeded the ICMFS guidelines. The use of these contaminated spices may pose risk to human health.

Prevalence of Salmonella in 11 Spices Offered for Sale from Retail Establishments and in Imported Shipments Offered for Entry to the United States

The U.S. Food and Drug Administration conducted a survey to evaluate Salmonella prevalence and aerobic plate counts in packaged (dried) spices offered for sale at retail establishments in the United States. The study included 7,250 retail samples of 11 spice types that were collected during November 2013 to September 2014 and October 2014 to March 2015. No Salmonella-positive samples (based on analysis of 125 g) were found among retail samples of cumin seed (whole or ground), sesame seed (whole, not roasted or toasted, and not black), and white pepper (ground or cracked), for prevalence estimates of 0.00% with 95% Clopper and Pearson's confidence intervals of 0.00 to 0.67%, 0.00 to 0.70%, and 0.00 to 0.63%, respectively. Salmonella prevalence estimates (confidence intervals) for the other eight spice types were 0.19% (0.0048 to 1.1%) for basil leaf (whole, ground, crushed, or flakes), 0.24% (0.049 to 0.69%) for black pepper (whole, ground, or cracked), 0.56% (0.11 to 1.6%) for coriander seed (ground), 0.19% (0.0049 to 1.1%) for curry powder (ground mixture of spices), 0.49% (0.10 to 1.4%) for dehydrated garlic (powder, granules, or flakes), 0.15% (0.0038 to 0.83%) for oregano leaf (whole, ground, crushed, or flakes), 0.25% (0.03 to 0.88%) for paprika (ground or cracked), and 0.64% (0.17 to 1.6%) for red pepper (hot red pepper, e.g., chili, cayenne; ground, cracked, crushed, or flakes). Salmonella isolates were serotyped, and genomes were sequenced. Samples of these same 11 spice types were also examined from shipments of imported spices offered for entry to the United States from 1 October 2011 to 30 September 2015. Salmonella prevalence estimates (based on analysis of two 375-g composite samples) for shipments of imported spices were 1.7 to 18%. The Salmonella prevalence estimates for spices offered for sale at retail establishments for all of the spice types except dehydrated garlic and basil were significantly lower than estimates for shipments of imported spice offered for entry.

Population dynamics and antimicrobial resistance of the most prevalent poultry-associated Salmonella serotypes

Salmonella spp. is the most predominant bacterial cause of foodborne gastroenteritis in humans. Due to the risk of human infection associated with poultry products and the prevalence of antimicrobial resistance, Salmonella also poses a significant challenge to commercial poultry production. During the last decade (2002 to 2012), the 12 most prevalent poultry-associated Salmonella serotypes (MPPSTs) were frequently and consistently isolated from poultry products in the United States. These MPPSTs and their percent prevalence in poultry products include Kentucky (4%), Enteritidis (2%) Heidelberg (2%), Typhimurium (2%), S. I 4,[5],12:i:- (0.31%), Montevideo (0.20%), Infantis (0.16%) Schwarzengrund (0.15%), Hadar (0.15%), Mbandaka (0.13%), Thompson (0.12%), and Senftenberg (0.04%). All MPPSTs except Kentucky are among the top 30 clinically significant serotypes that cause human illnesses in the United States. However with the exception of a few widely studied serotypes such as S. Enteritidis and Typhimurium, the ecology and epidemiology of the majority of MPPSTs still remain poorly investigated. Published data from the United States suggests that MPPSTs such as Heidelberg, Typhimurium, Kentucky, and Sentfenberg are more likely to be multi-drug resistant (MDR, ≥3 antimicobial classes) whereas Enteritidis, Montevideo, Schwarzengrund, Hadar, Infantis, Thompson, and Mbandaka are generally pan-susceptible or display resistance to fewer antimicobials. In contrast, the majority of MPPSTs isolated globally have been reported to display MDR phenotype. There also appears to be an international spread of a few MDR serotypes including Kentucky, Schwarzengrund, Hadar, Thomson, Sentfenberg, and Enteritidis, which may pose significant challenges to the public health. The current knowledge gaps on the ecology, epidemiology, and antimicrobial resistance of MPPSTs are discussed.

Evaluation of Three Real-Time PCR Methods for Detection of Salmonella from Cloves

The purpose of the study was to evaluate three real-time PCR platforms for rapid detection of Salmonella from cloves and to compare three different DNA extraction methods. Six trials were conducted with two clove cultivars, Ceylon and Madagascar, and three Salmonella serotypes, Montevideo, Typhimurium, and Weltevreden. Each trial consisted of 20 test portions. The preenrichment cultures were used to perform PCR for comparison of the effectiveness of U.S. Food and Drug Administration, Pacific Regional Laboratory Southwest (FDA-PRLSW), Applied Biosystems Inc. (ABI) MicroSEQ, and GeneDisc platforms for detection of Salmonella. Three DNA extraction methods were used: standard extraction method for each PCR platform, boil preparation, and LyseNow food pathogen DNA extraction cards. The results from real-time PCR correlated well with FDA Bacteriological Analytical Manual culture assay results, with a wide range of cycle threshold (C_T) values among the three PCR platforms for intended positive samples. The mean C_T values for MicroSEQ (16.36 ± 2.78) were significantly lower than for PRLSW (20.37 ± 3.45) and GeneDisc (23.88 ± 2.90) (P < 0.0001). Pairwise comparisons between PCR platforms using different DNA extraction methods indicate that the C_T values are inversely proportional to the relative DNA quantity (RDQ) yields by different platform-extraction combinations. The pairing of MicroSEQ and boil preparation generated the highest RDQ of 120 and the lowest average C_T value of 14.48, whereas the pairing of GeneDisc and LyseNow generated the lowest RDQ of 0.18 and the highest average C_T of 25.97. Boil preparation yielded higher RDQ than the other extraction methods for all three PCR platforms. Although the MicroSEQ platform generated the lowest C_T values, its sensitivity was compromised by narrow separations between the positive and negative samples. The PRLSW platform generated the best segregation between positive and negative groups and is less likely to produce false results. In conclusion, FDA-PRLSW was the most efficient PCR assay for Salmonella detection, and boil preparation was the best method for DNA extraction.

Development and Validation of a Cultural Method for the Detection and Isolation of Salmonella in Cloves

Detection of Salmonella in some spices, such as cloves, remains a challenge due to their inherent antimicrobial properties. The purpose of this study was to develop an effective detection method for Salmonella from spices using cloves as a model. Two clove varieties, Ceylon and Madagascar, were used in the study. Cloves were inoculated with Salmonella enterica subsp. enterica serotypes Montevideo, Typhimurium, or Weltevreden at about 1, 3, or 6 log CFU/25 g. Two test portion sizes, 10 and 25 g, were compared. After adding Trypticase soy broth (TSB) to the weighed cloves for preenrichment, three preenrichment methods were compared: cloves were left in the TSB for 24 h during preenrichment (PreE1), or the cloves-TSB mixture was shaken vigorously for 30 s (PreE2) or 60 s (PreE3), and the decanted material was transferred to a new bag for 24 h of preenrichment. The rest of the procedures were carried out according to the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM). At the low inoculation level (<1 log CFU/25 g), the detection rate was low across the three preenrichment methods, with the highest for PreE3 and lowest for PreE1. At the medium and high inoculation levels (3 and 6 log CFU/25 g), all samples from PreE2 and PreE3 were positive for Salmonella , whereas PreE1 produced only 12 positive samples from the 48 samples at the medium inoculation level and 38 positive samples from the 48 samples at the high inoculation level. Therefore, PreE3 with 25 g of cloves per sample was more effective than the other two tested methods. This newly designed method was then validated by comparing with the BAM method in six trials, with each trial consisting of 40 test samples. The results showed that PreE3 detected Salmonella from 88 of 120 inoculated test samples compared with only 31 positive from 120 test samples with the BAM method. Thus, our newly designed method PreE3 was more sensitive and easier to operate than the current BAM method for detection of Salmonella in cloves.

Prevalence and Antimicrobial Susceptibility of Enterobacteriaceae Isolated from Retail Pepper in Vietnam

To investigate the microbial quality of retail pepper in Vietnam, the enumeration and detection of Enterobacteriaceae and the screening of cefotaxime (CTX)-resistant coliforms were performed by using 84 commercial samples. Although Enterobacteriaceae were isolated from 78 samples, the number of Enterobacteriaceae was lower than 1.0 log CFU/g in 46 samples. For the detection of Enterobacteriaceae with the International Organization for Standardization methods, Salmonella spp., Escherichia coli, Klebsiella pneumoniae, Cronobacter sakazakii, and Enterobacter cloacae complex were isolated from 5, 12, 36, 19, and 30 samples, respectively. During screening of CTX-resistant coliforms, K. pneumoniae, C. sakazakii, and E. cloacae complex were isolated from 8, 1, and 21 samples, respectively. Seven K. pneumoniae and seven E. cloacae complex isolates obtained in the screening of CTX-resistant coliforms were resistant to at least one of the three third-generation cephalosporins (CTX, ceftazidime, and cefpodoxime). Moreover, one E. cloacae complex cluster IV and all K. pneumoniae isolates were positive for extended-spectrum β-lactamase genes or plasmid-mediated AmpC β-lactamase genes or both. Additionally, two extended-spectrum β-lactamase-producing K. pneumoniae isolates and one AmpC β-lactamase-producing E. cloacae complex cluster IV isolate were positive for the plasmid-mediated quinolone resistance determinants and also had amino acid alterations in the quinolone resistance-determining regions of GyrA and ParC. Furthermore, 10 E. cloacae complex isolates were positive for the plasmid-mediated fosfomycin resistance gene fosA. As pepper is often consumed without a heating process, the possible spread to humans of foodborne, opportunistic, and nosocomial infection pathogens or resistance genes from foods prepared or seasoned with pepper cannot be excluded. Therefore, it is necessary to handle pepper by using hygienic conditions during the cultivation, harvesting and processing steps.

Validation of Baking To Control Salmonella Serovars in Hamburger Bun Manufacturing, and Evaluation of Enterococcus faecium ATCC 8459 and Saccharomyces cerevisiae as Nonpathogenic Surrogate Indicators

This study was conducted to validate a simulated commercial baking process for hamburger buns to destroy Salmonella serovars and to determine the appropriateness of using nonpathogenic surrogates (Enterococcus faecium ATCC 8459 or Saccharomyces cerevisiae) for in-plant process validation studies. Wheat flour was inoculated (∼6 log CFU/g) with three Salmonella serovars (Typhimurium, Newport, or Senftenberg 775W) or with E. faecium. Dough was formed, proofed, and baked to mimic commercial manufacturing conditions. Buns were baked for up to 13 min in a conventional oven (218.3°C), with internal crumb temperature increasing to ∼100°C during the first 8 min of baking and remaining at this temperature until removal from the oven. Salmonella and E. faecium populations were undetectable by enrichment (>6-log CFU/g reductions) after 9.0 and 11.5 min of baking, respectively, and ≥5-log-cycle reductions were achieved by 6.0 and 7.75 min, respectively. D-values of Salmonella (three-serovar cocktail) and E. faecium 8459 in dough were 28.64 and 133.33, 7.61 and 55.67, and 3.14 and 14.72 min at 55, 58, and 61°C, respectively, whereas D-values of S. cerevisiae were 18.73, 5.67, and 1.03 min at 52, 55, and 58°C, respectivly. The z-values of Salmonella, E. faecium, and S. cerevisiae were 6.58, 6.25, and 4.74°C, respectively. A high level of thermal lethality was observed for baking of typical hamburger bun dough, resulting in rapid elimination of high levels of the three-strain Salmonella cocktail; however, the lethality and microbial destruction kinetics should not be extrapolated to other bakery products without further research. E. faecium demonstrated greater thermal resistance compared with Salmonella during bun baking and could serve as a conservative surrogate to validate thermal process lethality in commercial bun baking operations. Low thermal tolerance of S. cerevisiae relative to Salmonella serovars limits its usefulness as a surrogate for process validations.

[Survival of Salmonella Weltevreden and S. Senftenberg in black tiger shrimp under frozen storage]

Survival of Salmonella in black tiger shrimps during frozen storage was investigated following our previous study on Salmonella contamination in frozen shrimps imported into Japan. Salmonella (S.) Weltevreden and S. Senftenberg were inoculated onto the surface and inside of black tiger shrimps without the shell. After storage at -10 degrees C, -20 degrees C and -30 degrees C for 12 weeks, the Salmonella population decreased in all cases; the decrease was smallest at the lowest temperature. Viability of Salmonella inoculated onto the surface of the shrimp was greater than that inside the shrimp. In addition, viability of S. Senftenberg was greater than that of S. Weltevreden. These results suggest that hygienic handling during thawing of shrimps is important from the viewpoint of Salmonella contamination.

Salmonella prevalence in seafood imported into Japan

A total of 353 samples of 29 types of seafood were tested for Salmonella prevalence and total microbial population. Salmonella enterica serotype Weltevreden was isolated from 2 of 47 black tiger prawn samples. The contamination levels of Salmonella were in a range of <30 to 40 most probable number per 100 g. In addition, one sample of black tiger prawns and two samples of white shrimp were positive for Salmonella invA gene on PCR assay. Although the mean aerobic bacterial count was greater than 4 log CFU/g in most of the sample types, those in the two Salmonella-isolated samples of black tiger prawn were 7.48 and 5.18 log CFU/g, respectively. These results indicate the possibility that shrimp and prawns contribute to foodborne infections. The improvement of seafood quality is an important issue, and the information on contamination by pathogens should be provided as feedback to the originating country, with the aim of increasing safety.