Raw Almonds Research Articles

Perfil de ácidos graxos e fatores antinutricionais de amêndoas de pequi crua e torrada

O pequi é um dos frutos mais abundantes no Cerrado, sendo sua polpa muito apreciada na culinária regional, porém, sua amêndoa (também comestível) é pouco aproveitada. O consumo da amêndoa crua pode acarretar em problemas digestivos, devido à possível presença de fatores antinutricionais, assim como a torra pode alterar, nutricionalmente, a amêndoa. Este trabalho objetivou verificar a composição centesimal, o perfil de ácidos graxos e os fatores antinutricionais, em amêndoas de pequi crua e torrada (a 270ºC, por 15 minutos), oriundas do Estado de Goiás e submetidas às análises de composição centesimal (umidade, proteínas, lipídeos, cinzas, carboidratos e valor energético), perfil de ácidos graxos e fatores antinutricionais (inibidores de tripsina, tanino e fitatos). A composição centesimal e os fatores antinutricionais, respectivamente para as amêndoas crua e torrada, apresentaram os seguintes teores: umidade: 25,40% e 1,70%; cinzas: 3,90% e 4,60%; proteínas: 13,40% e 14,70%; lipídeos: 24,70% e 25,70%; carboidratos: 32,50% e 53,30%; e valor energético: 406,20 kcal/100 g e 503,00 kcal/100 g, com ausência de inibidores de tripsina e taninos com 1,21% e 1,17% e fitatos com 2,64% e 1,86%. No perfil de ácidos graxos, respectivamente para as amêndoas crua e torrada, foram obtidos 86,90% e 84,61% de ácidos saturados e 10,57% e 10,40% de insaturados. A torra das amêndoas não influenciou, significativamente (p > 0,05), somente a variável proteína, interferindo, assim, nas características nutricionais e antinutricionais.

Thermal inactivation of Salmonella enteritidis PT 30 in almond kernels as influenced by water activity.

Salmonellosis outbreaks related to consumption of raw almonds have encouraged the scientific community to study the inactivation kinetics of pathogens in this dry commodity. However, the low moisture content of the product presents a challenge for thermal control, because the time required to achieve the desired thermal inactivation of microorganisms increases sharply with reduced moisture content and water activity. In this study, we explored and modeled the heat inactivation of Salmonella enterica serovar Enteritidis PT 30 in almond cultivar 'Nonpareil' kernel flour at four water activity (a(w)) values (0.601, 0.720, 0.888, and 0.946) using four temperatures for each a(w). The results showed that the inactivation was well fitted by both Weibull distribution (R(2) = 0.93 to 1.00) and first-order kinetics (R(2) = 0.82 to 0.96). At higher a(w) values, the rate of inactivation increased and less time was needed to achieve the required population reduction. These results suggest that, to avoid deterioration of product quality, shorter process times at lower temperatures may be used to achieve desired inactivation levels of Salmonella Enteritidis PT 30 by simply increasing the moisture content of almonds. These goals could be achieved with the use of existing procedures already practiced by the food industry, such as washing or prewetting scalding before heat inactivation.

Chemical Characterization and Stability of the <i>Bombacopsis g</i><i>labra </i>Nut Oil

The aim of this study was to characterize the Bombacopis glabra nut oil (Malvaceae-Bombacoideae) by the determination of its lipid content and fatty acid composition with emphasis on the cyclopropenoid fatty acids (CPFA). The lipids were obtained by five different extraction conditions:(raw almonds: maceration with ethyl ether (I-MA) and n-hexane (II-MA), both at room temperature, and Soxhlet extraction with hexane for 6 (III-MA) and 12 h (IV-MA) and toasted almond: maceration with hexane at room temperature (V-MA)). Additionally, the oxidation stability of oil by the Rancimat test and the boiling point by thermal analysis (technical TG / DTG) were evaluated. The oil content ranged from 34.99 (I-MA) to 47.36% (IV-MA); oxidation stability was 4.18 h and the boiling point was 373.37 ℃. It should be noted that results about thermal and oxidative stability are been reported for the first time with respect to Bombacopis glabra nut oil. The major oil constituents were palmitic acid (56.06%) and esterculico (24.83%). The high percentage of CPFA oil, determined by NMR 1 H (26.2 to 30.9%) and GC-FID (26.5%), reinforce that the kernels of this species are not suitable for human consumption.

Cyanide and Amygdalin as Indicators of the Presence of Bitter Almonds in Imported Raw Almonds

Consumer complaints received by the U.S. Food and Drug Administration in August 2010 about raw organic almonds tasting "bitter" opened an investigation into the presence of bitter almonds in the imported product. Bitter almonds (Prunus amygdalus) contain the cyanogenic glucoside amygdalin, which hydrolyzes to produce cyanide. Ultraviolet-visible spectrophotometry was used to detect and quantitate cyanide, and liquid chromatography-mass spectrometry was utilized to detect amygdalin in the submitted samples. Control bitter almonds were found to contain 1.4 mg cyanide/g and an estimated level of 20-25 mg amygdalin/g. The questioned samples contained between 14 and 42 μg cyanide/g and were positive for the presence of amygdalin. Sweet almonds were found to be negative for both compounds, at levels of detection of 4 μg cyanide/g and 200 μg amygdalin/g.

Effect of Roasting Conditions on Color and Volatile Profile Including HMF Level in Sweet Almonds (Prunus dulcis)

Microwave, oven, and oil roasting of almonds were used to promote almond flavor and color formation. Raw pasteurized almonds were roasted in a microwave for 1 to 3 min, in an oven at 177 °C for 5, 10, 15, and 20 min; and at 135 and 163 °C for 20 min, and in oil at 135, 163, and 177 °C for 5 min and 177 °C for 10 min. Volatile compounds were quantified in the headspace of ground almonds, both raw and roasted, by selected ion flow tube mass spectrometry. Strong correlations were found between L value, chroma, and 5-(hydroxy methyl)-2- furfural; and were independent of roasting method. Raw almonds had lower concentrations of most volatiles than roasted almonds. Conditions that produced color equivalent to commercial samples were 2 min in the microwave, 5 min at 177 °C in the oven, and 5 min at 135 °C in oil. Microwave heating produced higher levels of most volatiles than oven and oil roasting at commercial color. Sensory evaluation indicated that microwave-roasted almonds had the strongest aroma and were the most preferred. Oil-roasted almonds showed significantly lower levels of volatiles than other methods, likely due to loss of these volatiles into the oil. Alcohols such as benzyl alcohols and strecker aldehydes including benzaldehyde and methional were at higher concentrations than other volatiles in roasted almonds. The oxidation of lipids to form alkanals such as nonanal and degradation of sugars to form furan type compounds was also observed. The Maillard reaction contributed to the formation of more of the total volatiles in almonds than the lipid oxidation reaction. The level of 5-(hydroxy methyl)-2- furfural (HMF), color, volatile profile, and sensory perception can be used to develop the best roasting method, time, and temperature for almonds. The rate of color development and the production of volatiles differ under different roasting conditions. Based on the color, volatile, and sensory assessments of the 3 almonds, the use of microwave technology as a process for roasting almonds reduces processing time and leads to an almond product with better flavor than oven or oil roasting.

Review of Current Technologies for Reduction of Salmonella Populations on Almonds

After the 2001 and 2004 Salmonellosis outbreaks that were associated with raw almonds, ensuring the microbial safety of almonds by treating them to achieve a minimum 4-log reduction of Salmonella population became mandatory in California, the world’s largest almond producer. In this paper, we summarize potential pathways of microbial contamination during almond production and manufacturing. Furthermore, we review sanitization technologies, including chemical, thermal, and non-thermal methods, as well as proprietary systems with regard to microbial and sensory quality of almonds and compare various aspects of their use during almond processing.

Potential Health Benefits of Almond Skin

Nut consumption and almond in particular, has been shown to have beneficial effects on blood glucose levels in individuals with type-2 diabetes and prediabetes, with statistically-significant improvements in fasting levels of glucose, insulin, insulin sensitivity and LDL-cholesterol [1,2]. Compared to other tree nuts, almonds are particularly rich in dietary fiber (12%), mostly insoluble, which is mainly present in the skin. Both natural almond skin, present in raw almonds, and blanched skin, a by-product of the almond processing industry from blanching, have been recognised as useful ingredients for the control of oxidative processes in food products and as a potential prebiotics [3,4]. Prebiotics are foods or food ingredients able to modulate the colonic microbiota and are characterized by their resistance to gastric acidity, hydrolysis by mammalian enzymes and gastrointestinal absorption. They are fermentable by intestinal microbiota and cause selective stimulation of the growth and/or activity of intestinal bacteria associated with health and well-being [5-7]. Roberfroid [8] defined a prebiotic as ‘a selectively fermented ingredient that allows specific changes, both in the composition and/ or activity in the gastrointestinal microbial community that confers benefits upon host well being and health’. The Prebiotic Index (PI) is a comparative relationship between the growth of beneficial bacteria and the less desirable ones, in relation to the changes of the total number of bacteria. The PI obtained with natural and blanched almond skins after 8 and 24h incubation was comparable with the values obtained with Fructo-Oligo Saccharides (FOS), used as positive control [4]. Other health promoting compounds present in almond skins are polyphenols [9], which have been shown to be protective agents against cancer and cardiovascular disease. Among polyphenols, flavonoids are secondary metabolites well documented for their biological effects, including anticancer, anti viral, antimutagenic and anti-inflammatory activities [10-11]. Almond polyphenols have been found to be bioaccessible in the upper Gastro Intestinal (GI) tract and potentially available for absorption [12, 13]. Higher release of flavonoids and phenolic acids was observed with natural skins compared with blanched skins in both simulated gastric and gastric plus duodenal compartment [12]. The polyphenols present in almond skins are also active as antimicrobials against a range of food-borne pathogens. There is an increased effort in trying to avoid foods with chemical preservatives and this is manifested by the food industries growing interest in finding natural compounds with antimicrobial activity. The enhanced demand for natural and minimally processed ingredients is also attributed to the legislations governing the use of current preservatives. A number of aromatic plant oils have found industrial applications as preservatives of raw and processed foods. Almond skin polyphenolsrich fractions were found active against Listeria monocytogenes and Staphylococcus aureus. Natural almond skins were also active against the Gram-negative food-borne pathogen Salmonella enterica [14]. In agreement with the higher polyphenolic content, natural almond skins were more active than blanched skins.

X-Ray Irradiation as a Microbial Intervention Strategy for Food

First recognized in 1895, X-ray irradiation soon became a breakthrough diagnostic tool for the dental and medical professions. However, the food industry remained slow to adopt X-ray irradiation as a means for controlling insects and microbial contaminants in food, instead using gamma and electron beam (E-beam) irradiation. However, the reinvention of X-ray machines with increased efficiency, combined with recent developments in legislation and engineering, is now allowing X-ray to actively compete with gamma irradiation and E-beam as a microbial reduction strategy for foods. This review summarizes the historical developments of X-rays and discusses the key technological advances over the past two decades that now have led to the development of several different X-ray irradiators capable of enhancing the safety and shelf life of many heat-sensitive products, including lettuce, spinach, tomatoes, and raw almonds, all of which have been linked to high profile outbreaks of foodborne illness.

Acrylamide Formation in Almonds (Prunus dulcis): Influences of Roasting Time and Temperature, Precursors, Varietal Selection, and Storage

Acrylamide is a probable human carcinogen that is found in many roasted and baked foods. This paper describes two sensitive and reliable LC-(ESI)MS/MS methods for the analysis of (1) acrylamide and (2) common acrylamide precursors (i.e., glucose, fructose, asparagine, and glutamine) in raw and roasted almonds. These methods were used to evaluate the impact of roasting temperatures (between 129 and 182 °C) and times on acrylamide formation. Controlling the roasting temperature at or below 146 °C resulted in acrylamide levels below 200 ppb at all roasting times evaluated. Six varieties of almonds collected in various regions of California over two harvest years and roasted at 138 °C for 22 min had acrylamide levels ranging from 117 ± 5 μg/kg (Sonora) to 221 ± 95 μg/kg (Butte) with an average of 187 ± 71 μg/kg. A weak correlation between asparagine content in raw almonds and acrylamide formation was observed (R(2) = 0.6787). No statistical relationship was found between acrylamide formation and almond variety, orchard region, or harvest year. Stability studies on roasted almonds indicated that acrylamide levels decreased by 12.9-68.5% (average of 50.2%) after 3 days of storage at 60 °C. Short-term elevated temperature storage may be another approach for mitigating acrylamide levels in roasted almonds.

Risk of salmonellosis from consumption of almonds in the North American market

Salmonellosis outbreaks from consumption of raw almonds in 2001 and 2004 led to regulations that require mandatory treatment of almonds sold in North America to give a minimum 4-log reduction of Salmonella. This study aims to: 1) assess the risk of salmonellosis associated with almond consumption in North America, with current treatments in effect; 2) determine the resilience of the current production system to increases in prevalence or concentration of Salmonella on almonds; 3) assess the impact of treating less than 100% of the crop; and 4) investigate conditions that could explain the number of cases associated with the 2001 outbreak. Risk was assessed using a Monte Carlo simulation, based on an established dose–response relationship. Data for almond amounts sold, Salmonella prevalence and concentration on almonds, storage time and temperature at different handling steps, population reductions during storage at various temperatures and with different treatments, and consumer handling were based on data from published sources and almond industry or academic expert opinion. What-if scenarios were evaluated for Salmonella prevalence varying from 1 to 65%, concentrations of Salmonella varying from 1 to 120MPN/100g, and portions of untreated crop varying from 0 to 10%. The estimated incidence of salmonellosis in North America from almonds as currently treated is on average 0.008 cases per billion servings (with an estimated 6.6billion servings consumed annually). Increases in Salmonella prevalence to 25%, mean concentrations above 25MPN/100g, or leaving 0.05% of the crop untreated all resulted in an arithmetic mean risk greater than 1case/year (with geometric means remaining below 1case/year for all variables). Assuming 4000kg at a prevalence of 65% (observed in recalled lots) and an average concentration of 120MPN/100g in raw almonds (back calculated from levels in recalled almonds) predicted over the 2800 cases estimated for the 2001 outbreak. Applying a 4-log reduction to these almonds reduced the average number of predicted cases to less than a single case. The current regulation is effective in maintaining the risk of salmonellosis from consumption of almonds below an arithmetic mean of 1case/year, although significant increases in either prevalence or concentration, or small increases in proportion of untreated almonds would frequently lead to exceeding this threshold.

Survival of Salmonella Enteritidis PT 30 on inoculated almond kernels in hot water treatments

Almonds are blanched by exposure to hot water or steam-injected water to remove the pellicle (skin) from the kernel. This study evaluated the survival of Salmonella Enteritidis PT 30, Salmonella Senftenberg 775W and Enterococcus faecalis on whole raw almond kernels exposed to hot water. Whole, inoculated (7 to 9logCFU/g) Nonpareil almonds (40g) were submerged in 25L of water maintained at 60, 70, 80 and 88°C. Almonds were heated for up to 12min, drained for 2s, and transferred to 80mL of cold (4°C) tryptic soy broth. Almonds in broth were stomached at high speed for 2min, serially diluted, plated onto tryptic soy and bismuth sulfite agars (Salmonella) or bile esculin agar (Enterococcus) and incubated at 37°C for 24 and 48h, respectively. D values of 2.6, 1.2, 0.75 and 0.39min were calculated for exposure of S. Enteritidis PT 30 to water at 60, 70, 80 and 88°C, respectively; the calculated z value was 35C°. D values determined for Salmonella Senftenberg 775W and E. faecalis at 88°C were 0.37 and 0.36min, respectively. Neither Salmonella serovar could be recovered by enrichment of 1-g samples after almonds inoculated at 5logCFU/g were heated at 88°C for 2min. These data will be useful to validate almond industry blanching processes.

Controlled temperature grinding under modified atmosphere for Almond (Prunus Dulcis) paste production

The quality of the raw material and the processing conditions have a great influence on the nutritional properties of finished products. This research is focused on almond paste production and aims at developing a new production process to deliver the high nutritional content of the raw almonds into the finished product. Raw almonds are composed mainly of fats (approx. 50%) and proteins (approx. 25%), and are particularly rich in omega 6 fatty acids, and are hence exposed to denaturation and oxidation phenomena during the traditional grinding/homogenization process. The study involved the analysis of six different local cultivars based upon the main nutritional indicators (protein content, vitamins, and fatty acids) which resulted in the determination of the cultivar tuono as the one with the best nutritional properties. The further step consisted in establishing an innovative production process involving controlled atmosphere and refrigerated grinding with the aim of preserving the nutritional value of the raw material. Finally an experimental comparison of the product obtained with the proposed production process and the traditional method showed an average incremental gain of 27% and 21% in the protein and fat content, respectively. Keywords: Almonds; Food Processing Aspects; Lipid Oxidation International Journal of Engineering, Science and Technology, Vol. 2, No. 9, 2010, pp. 69-82

Cover Caption

On the cover: Cell structure of raw almond from “Image Analysis of Microstructural Changes in Almond Cotyledon as a Result of Processing” by Aylin Altan, Kathryn L. McCarthy, Rohan Tikekar, Michael J. McCarthy, and N. Nitin; p E216.

Infrared pasteurization of raw almonds

Due to outbreaks of salmonellosis associated with whole raw almonds, an infrared (IR) pasteurization process was investigated for its efficacy in improving the safety of raw almonds. After almonds were heated to 100, 110 and 120 °C with IR, they were cooled at ambient temperature to a holding temperature of 70, 80 or 90 °C before being transferred to a custom-designed holding device for different time periods up to 60 min. We observed that holding almonds at 90 °C for 10–15 min reduced the Pediococcus population size by more than 5-log and holding at 80 °C for longer than 22 min provided more than 4-log reduction, thus satisfying the targeted 4-log reduction required in the almond industry. The L ∗ a ∗ b ∗ color values of whole almonds were not affected significantly ( P > 0.05) by the IR process whereas the a ∗ and b ∗ color values of ground almonds changed significantly ( P < 0.05). The sensory panel did not detect any significant difference ( P > 0.01) in appearance, texture, flavor and overall quality of pasteurized almonds compared with untreated samples.

Most-probable-number determination of salmonella levels in naturally contaminated raw almonds using two sample preparation methods.

Pathogens occurring in particulate foods may be unevenly distributed, which may impact interpretation of most-probable-number (MPN) values. The MPN analysis of Salmonella in naturally contaminated raw almonds was conducted using two sample preparation methods. Raw almond kernels (3,698 samples) and inshell almonds (455 samples) were collected from almond processors throughout California during the 2006 and 2007 harvests, and 100-g samples were enriched for Salmonella. The prevalence of Salmonella on kernels and inshell almonds was 1.6 and 0.9%, respectively, in 2006, and 0.83 and 2.2%, respectively, in 2007. Almond kernel samples from 2006 were further enriched for Salmonella, and levels of the organism were determined for positive samples by three-tube MPN analysis (25 g, 2.5 g, 0.25 g). Almonds were either divided into subsamples prior to blending and enrichment (method A), or samples were blended in enrichment broth prior to preparation of subsamples (method B). Salmonella was not isolated (<1.2 MPN/100 g) upon retesting of 19 of 31 (method A) or 23 of 29 (method B) positive samples. When detected, levels were 1.4 to 15.5 MPN/100 g (average 2.3 MPN/100 g) or 1.4 to 18.3 MPN/100 g (average 2.1 MPN/100 g) using methods A or B, respectively. A total of 23 different Salmonella serovars were identified from the original almond samples. Salmonella Muenchen was the most frequently isolated serovar (15%) from the 53 Salmonella-positive samples, followed by Newport (12%), Enteritidis (10%), and Typhimurium (8%). No correlation was found between presence of Salmonella and E. coli levels, aerobic plate counts, or counts of yeasts or molds.

Almond quality as influenced by radio frequency heat treatments for disinfestation

Increased regulation of chemical fumigants has forced the almond industry to seek alternatives for postharvest control of insect pests in raw almonds. This paper reports developments of non-chemical treatment for postharvest disinfestation of almonds using radio frequency (RF) energy. A pilot-scale 27 MHz RF unit was used to evaluate effects of a RF treatment protocol on quality attributes in treated in-shell and shelled almond samples. The RF treatment protocol used 0.75 kW RF power, a forced hot air at 63 °C, back and forth movements on the conveyor at 0.56 m/min, and single mixing, which all improved the final heating uniformity. RF treatments sharply reduced the heating time from 86 and 137 min for hot air heating to only 6.4 and 8.8 min for the center of 1.5 kg in-shell and 2.4 kg shelled almond samples to reach 63 °C, respectively. Almond quality was not affected by the RF treatments because peroxide values, fatty acid and kernel color of treated almonds were better than or similar to untreated controls after 20 d at 35 °C, simulating 2 years of storage at 4 °C. RF treatments did not significantly affect the kernel moisture content of both types of almonds but reduced the moisture content in the shell. RF treatments may hold great potential to replace chemical fumigation for disinfesting almonds.

Effectiveness of Superheated Steam and Gas Catalytic Infrared Heat Treatments to Inactivate Salmonella on Raw Almonds

The majority of the almond-related outbreaks have been associated with Salmonella. Therefore, it is necessary to find an effective method to inactivate these organisms on the raw almond before distribution in the market. This study was conducted to assess the effectiveness of superheated steam (SHS) treatments followed by catalytic infrared (IR) heat treatment to inactivate Salmonella populations on raw almond and to determine the effect of these treatments on the quality of raw almond. It has been found that SHS treatment for 70 seconds followed by catalytic IR heat treatment for 70 seconds was able to reduce 5.73 +/- 0.11 log CFU/g Salmonella population, and no survivors were found in the enrichment medium. The overall visual quality parameters of both treated and nontreated almonds were found within the acceptable limit. Therefore, SHS treatments for 70 seconds followed by catalytic IR heat treatment for 70 seconds could be an effective decontamination method for raw almonds.

Comparison of Genotypes of Salmonella enterica Serovar Enteritidis Phage Type 30 and 9c Strains Isolated during Three Outbreaks Associated with Raw Almonds

In 2000 to 2001, 2003 to 2004, and 2005 to 2006, three outbreaks of Salmonella enterica serovar Enteritidis were linked with the consumption of raw almonds. The S. Enteritidis strains from these outbreaks had rare phage types (PT), PT30 and PT9c. Clinical and environmental S. Enteritidis strains were subjected to pulsed-field gel electrophoresis (PFGE), multilocus variable-number tandem repeat analysis (MLVA), and DNA microarray-based comparative genomic indexing (CGI) to evaluate their genetic relatedness. All three methods differentiated these S. Enteritidis strains in a manner that correlated with PT. The CGI analysis confirmed that the majority of the differences between the S. Enteritidis PT9c and PT30 strains corresponded to bacteriophage-related genes present in the sequenced genomes of S. Enteritidis PT4 and S. enterica serovar Typhimurium LT2. However, PFGE, MLVA, and CGI failed to discriminate between S. Enteritidis PT30 strains related to outbreaks from unrelated clinical strains or between strains separated by up to 5 years. However, metabolic fingerprinting demonstrated that S. Enteritidis PT4, PT8, PT13a, and clinical PT30 strains metabolized L-aspartic acid, L-glutamic acid, L-proline, L-alanine, and D-alanine amino acids more efficiently than S. Enteritidis PT30 strains isolated from orchards. These data indicate that S. Enteritidis PT9c and 30 strains are highly related genetically and that PT30 orchard strains differ from clinical PT30 strains metabolically, possibly due to fitness adaptations.

DEVELOPMENT OF AN ALMOND LEXICON TO ASSESS THE SENSORY PROPERTIES OF ALMOND VARIETIES

ABSTRACT A unique comprehensive sensory lexicon for describing the appearance, aroma, flavor and texture attributes of almonds was developed by a nine‐member panel with extensive experience in descriptive analysis. The almond lexicon was then used to profile the sensory properties of 20 almond samples obtained from three growing regions in California over two harvest years and encompassing seven major almond varieties, to better understand the natural variability in raw almonds. Range graphs were plotted to depict the intensity range (minimum to maximum score) for a given attribute across all samples evaluated for a variety. Descriptive analysis results revealed that the major almond varieties tested had a range of inherent variability and that specific varieties had unique attributes. Distinct walnut, tea and squash flavor aromatics were detected in only some almond varieties. Appearance, aroma, basic taste and chemical feeling factor attribute ranges were generally small and consistent among varieties. PRACTICAL APPLICATIONSThe detailed, working almond lexicon created in this study will provide researchers, producers and manufacturers with an effective platform to communicate observations for the evaluation of almonds. The sensory attribute assessment of almond varieties obtained from different regions, growers and harvest years allows for a better understanding of the natural variability in almonds. Establishing the range of natural variability found in raw almonds of the major California varieties provides the basis for future research on the effects of processing treatments on the sensory characteristics of almonds.

Evaluation of steam pasteurization in controllingSalmonellaserotype Enteritidis on raw almond surfaces

To investigate the efficacy of steam pasteurization for reducing Salmonella serotype Enteritidis on raw almond surfaces. Nonpareil almonds were inoculated to 10(7-8) CFU g(-1) with a Salm. Enteritidis cocktail (Salm. Enteritidis 43353, ME-13, ME-14) or Salm. Enteritidis phage type 30, dried overnight and subjected to steam treatments through a pilot-sized vertical pasteurization machine for 5, 15, 25, 35, 45, 55 and 65 s to investigate the effect of steam on a single layer of almond. Survival of Salm. Enteritidis was evaluated with tryptic soy agar and xylose lysine desoxycholate overlay for total and healthy cells, respectively. No significant differences (P > 0.05) in reduction were observed between the Salm. Enteritidis cocktail and Salm. Enteritidis PT 30 inoculum. Reduction of Salm. Enteritidis increased as a function of treatment time, with 25 s being sufficient to achieve a 5-log reduction. Discolouration and visible formation of wrinkles were observed following steam pasteurization of more than 35 s. Steam pasteurization of 25 s is sufficient to achieve a 5-log reduction of Salm. Enteritidis inoculated on raw almonds without visual quality degradation. Steam pasteurization is an effective alternative to reduce or prevent Salm. Enteritidis contamination on raw almonds.