Shelf-life Reduction as an Emerging Problem in Cooked Hams Underlines the Need for Improved Preservation Strategies.

Cooked hams have gained an important position within the delicatessen market. Nowadays, consumers not only demand superior sensory properties but also request low levels of sodium and fat and the absence of conventional chemicals and preservatives used for the increase of the technological yield and shelf-life of the products. As a result, products that apply strict quality certificates or ''clean'' labels become increasingly important. However, such cooked hams suffer from a limited shelf-life. Besides some physicochemical effects, this is mainly due to microbial impact, despite the application of modified-atmosphere-packaging and chilling. Microbial spoilage is mostly due to the metabolic manifestation of lactic acid bacteria and Brochothrix thermosphacta, although Enterobacteriaceae and yeasts may occur too. Several preservation strategies have been developed to prolong the shelf-life of such vulnerable cooked meat products by targeting the microbial communities, with different rates of success. Whereas high-pressure treatments do not always pose a straightforward solution, a promising strategy relates to the use of bioprotective cultures containing lactic acid bacteria. The latter consist of strains that are deliberately added to the ham to outcompete undesirable microorganisms. Spoilage problems seem, however, to be specific for each product and processing line, underlining the importance of tailor-made solutions.

Evaluation of certain food additives.

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for five food additives (magnesium dihydrogen diphosphate; mineral oil (medium and low viscosity) classes II and III; 3-phytase from Aspergillus niger expressed in Aspergillus niger; serine protease (chymotrypsin) from Nocardiopsis prasina expressed in Bacillus licheniformis; and serine protease (trypsin) from Fusarium oxysporum expressed in Fusarium venenatum) and 16 groups of flavouring agents (aliphatic and aromatic amines and amides; aliphatic and aromatic ethers; aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers containing furan substitution; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; amino acids and related substances; epoxides; furfuryl alcohol and related substances; linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; miscellaneous nitrogen-containing substances; phenol and phenol derivatives; pyrazine derivatives; pyridine, pyrrole and quinoline derivatives; saturated aliphatic acyclic branched-chain primary alcohols, aldehydes and acids; simple aliphatic and aromatic sulfides and thiols; sulfur-containing heterocyclic compounds; and sulfur-substituted furan derivatives). Specifications for the following food additives were revised: ethyl cellulose, mineral oil (medium viscosity), modified starches and titanium dioxide. Annexed to the report are tables summarizing the Committee's recommendations for dietary exposures to and toxicological evaluations of the food additives and flavouring agents considered.

Chemistry, safety, and regulatory considerations in the use of nitrite and nitrate from natural origin in meat products - Invited review.

Nitrite and nitrate have been traditionally used for the preservation of meat products because of the effective antimicrobial action of nitrite against Clostridium botulinum, the outgrowth of its spores as well as other bacteria. However, the use of nitrite and nitrate has been questioned in last half century due to the possible generation of N-nitrosamines through reaction of nitrite with secondary amines. Nitrite replacement strategies began in the 70s addressing these issues and instigated searches for natural alternatives to nitrate and nitrite, or for natural sources of nitrite and nitrate such as vegetable extracts. These alternatives have been considered by producers and consumers as an attractive practice even though they may also have some risks. This manuscript reviews and discusses the chemistry, safety, and regulatory considerations in the use of nitrite and nitrate from natural origin for the preservation of meat products.

Waxing and cultivar affect Salmonella enterica persistence on cucumber (Cucumis sativus L.) fruit.

A dearth of knowledge exists on the pathogen-commodity association of Salmonella enterica on cucumber, despite cucumbers being implicated in multiple salmonellosis outbreaks in recent years in the U.S. Data are lacking on cultivar susceptibility to Salmonella colonization in relation to heterogeneity in fruit surface morphology. Further, fruit waxing is a common practice in wholesale cucumber to preserve the water content of fruit and prolong shelf-life, but its impact on epiphytic microbiota is not well studied. This study investigated the survival of Salmonella Newport and S. Javiana on the surface of six cucumber cultivars of varying surface morphology and the effect of fruit waxing on the persistence of S. Newport. S. Newport and S. Javiana were spot inoculated onto fruit of cultivars 'Marketmore 97', 'Patio Snacker' and 'Corinto' (varieties with trichomes or spines), and 'Bella', 'Pepinex' and 'Summer Dance' (glabrous or smooth varieties). Cucumbers were held at room temperature for 24 h before inoculated sections of exocarp were excised for enteropathogen enumeration. S. Javiana persisted at higher populations than S. Newport (1.0 and 1.5 log CFU g-1 exocarp decline, respectively) after 24 h (P < 0.05). Fruit waxing lessened S. Newport population decline after 24 h on all cultivars tested (P < 0.01). While there was a ~2 log CFU g-1 exocarp decline in populations on unwaxed cucumbers, the reduction on waxed cucumbers was ~1 log CFU g-1 exocarp. A cultivar effect was also observed; 'Summer Dance' supported consistently higher and 'Corinto' and 'Marketmore 97' (though for S. Javiana only) consistently lower Salmonella levels. Cultivars with trichomes were associated with lower populations than glabrous cultivars (P < 0.05). Our data showed that Salmonella persistence on fruit differed for the two serotypes tested and that cultivar differences play a role in determining cucumber surface favourability for pathogen colonization. Additionally, fruit waxing may elevate the risk of Salmonella persistence on cucumber.

Optimization of bioactive preservative coatings of starch nanocrystal and ultrasonic extract of sour lemon peel on chicken fillets.

Starch nanocrystal (S-NC) was produced after sulfuric acid hydrolysis of potato starch granules and then characterized by laser diffraction particle size analyzer, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Response surface methodology (RSM) was applied to optimize S-NC (2-10%) concentration, sour lemon peel extract (SLPE, 2.5-12.5%) amount, mixing temperature (M-TE, 25-65 °C) and mixing time (M-TI,15-75 min) in the preparation of bioactive coating solutions to develop the high-quality chicken fillets during the cold-storage. The optimized conditions for achieving the highest DPPH inhibition percentage (89.14%), antibacterial activity (Staphylococcus aureus, 3.58-mm; Escherichia coli, 3.14-mm; Listeria monocytogenes, 2.31-mm and Salmonella enterica, 2.24-mm) and lightness value (77.82) and the lowest redness (6.69), yellowness (13.21) values and viscosity (27.5 mPa.s) were 4.0% S-NC, 5.62% SLPE, 51.17 °C M-TE and 43.29 min M-TI. Spraying the optimal coating solution on chicken fillets led to a significant improvement in their physicochemical, textural and sensory characteristics compared to the control during 12-day cold-storage.

Effects of natural compounds on microbial safety and sensory quality of Fior di Latte cheese, a typical Italian cheese.

This work presents a preliminary study to assess the efficiency of plant essential oils as natural food preservatives in Fior di Latte cheese. Selected compounds were directly dissolved into Fior di Latte brine. Packaged Fior di Latte samples were stored at 10 degrees C for about 6 d. The cell loads of spoilage and useful microorganisms were monitored to calculate the microbial acceptability limit. Results show that some tested compounds were not acceptable by the panel from a sensorial point of view. Most compounds did not affect the microbial acceptability limit value to a great extent, and only a few such as lemon, sage, and thyme markedly prolonged the microbial acceptability limit of the investigated fresh cheese. Moreover, the above active agents exerted an inhibitory effect on the microorganisms responsible for spoilage without affecting the dairy microflora.

Controlling pests in dry-cured ham: A review.

Dry-cured hams can become infested with ham mites, red-legged beetles, cheese skippers, and larder beetles during the aging process. Though other methods may be used for beetles and cheese skippers, methyl bromide is the only available fumigant that is effective at controlling ham mites in dry-cured ham plants in the United States. However, methyl bromide will be phased out of all industries by approximately 2015. This paper will review and explore potential alternatives that have been investigated to determine their feasibility for replacing methyl bromide to control pest infestations in dry-cured ham plants in the United States. Potential alternatives include: 1) fumigants such as phosphine and sulfuryl fluoride; 2) physical control approaches through cold treatment, modified atmosphere, inert dusts, etc.; 3) pesticides and bioactive compounds; 4) food-grade processing aids. The most promising potential alternatives to date include the use of propylene glycol on the ham surface, the exploration of alternative fumigants, and implementation of an integrated pest management plan.

Benzoic and sorbic acid in soft drink, milk, ketchup sauce and bread by dispersive liquid-liquid microextraction coupled with HPLC.

Benzoic acid and sorbic acid are widely used for food preservation. These preservatives are generally recognised as safe. The aim of this study was to determine the level of benzoic and sorbic acid in food samples that are usually consumed in Iran. Therefore, 54 samples, including 15 soft drinks, 15 ultra-high-temperature milk, 15 ketchup sauces and 9 bread samples, were analysed by high-performance liquid chromatography with UV detection. Benzoic acid was detected in 50 (92.5%) of the samples ranging from 3.5 to 1520 µg mL⁻¹, while sorbic acid was detected in 29 (50.3%) samples in a range of 0.8 and 2305 µg mL⁻¹. Limits of detection and limits of quantification for benzoate were found to be 0.1 and 0.5 µg mL⁻¹, respectively, and for sorbate 0.08 and 0.3 µg mL⁻¹, respectively. The results showed that benzoic acid and sorbic acid widely occur in food products in Iran.

Food safety--then and now. A Bicentennial study.

Although this is our Bicentennial year, effective measures to insure food safety date back less than a century. The first efforts toward reform were begun by Accum in England early in the nineteenth century, but they did not bear fruit there--in even a beginning form--until 1875, when Parliament passed the Sales of Food and Drug Act. Legislation came even later in the U.S.--not until the first Pure Food and Drugs Act became law in 1906, largely due to the unswerving efforts for almost twenty years of Harvey W. Wiley. Today, the scientific approach is applied in developing criteria for judging the safety of food and for regulations to insure that healthful, safe food reaches the consumer. Amendments to this law in 1938 and 1958 have further strengthened the protection the public is provided in its food supply. Today, the substances on the "GRAS" list are being examined individually to determine their safety when used in foods. However, the legalistic invoking of absolutes, as in the Delaney Clause of the 1958 amendments, goes beyond the limits of common sense. The challenge is to insure the benefits of science and technology without the loss of basic individual freedom.

Estimates of the theoretical maximum daily intake of erythorbic acid, gallates, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in Italy: a stepwise approach.

The three recent EU directives which fixed maximum permitted levels (MPL) for food additives for all member states also include the general obligation to establish national systems for monitoring the intake of these substances in order to evaluate their use safety. In this work, we considered additives with primary antioxidant technological function for which an acceptable daily intake (ADI) was established by the Scientific Committee for Food (SCF): gallates, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and erythorbic acid. The potential intake of these additives in Italy was estimated by means of a hierarchical approach using, step by step, more refined methods. The likelihood of the current ADI to be exceeded was very low for erythorbic acid, BHA and gallates. On the other hand, the theoretical maximum daily intake (TMDI) of BHT was above the current ADI. The three food categories found to be main potential sources of BHT were "pastry, cake and biscuits", "chewing gums" and "vegetables oils and margarine"; they overall contributed 74% of the TMDI. Actual use of BHT in these food categories is discussed, together with other aspects such as losses of this substance in the technological process and percentage of ingestion in the case of chewing gums.

Use of a most probable number method modified with a deoxyribonucleic probe to monitor control by food preservatives of natural Salmonella contamination in animal meat meals.

A most probable number (MPN) technique using a DNA probe was developed for determination of Salmonella in naturally contaminated meat meals. The method eliminated the need for 180 selective plates and 75 selective tubes and saved 27 h when compared with a traditional technique; yet it still yielded identical MPN of Salmonella per 100 g in five naturally contaminated samples. The method was used to monitor the effect of a commercial food preservative (Sal Curb) at 0, .25, .50, 1.0, and 2.0% in meat meals with initial contaminations of 1,100, 93, or 7 MPN organisms/100 g. The preservative greatly reduced MPN in the 1,100 and 93 MPN samples in a time and dose-dependent manner, but in the sample with 7 MPN organisms/100 g of material, it resulted in 0 MPN organisms per 100 g after 24 h at all levels tested.

Action on preservatives in fresh pet food.

In late 1995 and early 1996, Sydney vet Dr Bob Steel reported first-hand experience with a cat dying from thiamine deficiency. This deficiency was attributable to the presence of sulfur dioxide in fresh pet food which was fed to the cat over a period of time. The diagnosis was confirmed, as was the presence of sulfur dioxide in significant levels. Since that time, Dr Steel and the AVA have pursued the issue of preservatives (specifically those producing sulfur dioxide) in fresh pet food. An update on that work follows.

Evaluating food additives as antifungal agents against Monilinia fructicola in vitro and in hydroxypropyl methylcellulose-lipid composite edible coatings for plums.

Common food preservative agents were evaluated in in vitro tests for their antifungal activity against Monilinia fructicola, the most economically important pathogen causing postharvest disease of stone fruits. Radial mycelial growth was measured in Petri dishes of PDA amended with three different concentrations of the agents (0.01-0.2%, v/v) after 7 days of incubation at 25 °C. Thirteen out of fifteen agents tested completely inhibited the radial growth of the fungus at various concentrations. Among them, ammonium carbonate, ammonium bicarbonate and sodium bicarbonate were the most effective while sodium acetate and sodium formate were the least effective. The effective agents and concentrations were tested as ingredients of hydroxypropyl methylcellulose (HPMC)-lipid edible coatings against brown rot disease on plums previously inoculated with M. fructicola (curative activity). 'Friar' and 'Larry Ann' plums were inoculated with the pathogen, coated with stable edible coatings about 24h later, and incubated at 20 °C and 90% RH. Disease incidence (%) and severity (lesion diameter) were determined after 4, 6, and 8 days of incubation and the 'area under the disease progress stairs' (AUDPS) was calculated. Coatings containing bicarbonates and parabens significantly reduced brown rot incidence in plums, but potassium sorbate, used at 1.0% in the coating formulation, was the most effective agent with a reduction rate of 28.6%. All the tested coatings reduced disease severity to some extent, but coatings containing 0.1% sodium methylparaben or sodium ethylparaben or 0.2% ammonium carbonate or ammonium bicarbonate were superior to the rest, with reduction rates of 45-50%. Overall, the results showed that most of the agents tested in this study had significant antimicrobial activity against M. fructicola and the application of selected antifungal edible coatings is a promising alternative for the control of postharvest brown rot in plums.

Atividade antibacteriana de óleos essenciais de café verde e torrado (Coffea arabica), Cacau (Theobroma cacao), casca e folha de canela do ceilão (Cinnamomum zeylanicun) / Antibacterial activity of essential oils from green and roasted coffee (Coffea arabica), Cacau (Theobroma cacao), bark and cinnamon leaf from Ceylon (Cinnamomum zeylanicun)

Diversos conservantes naturais têm sido utilizados na inativação de micro-organismos, sem efeitos adversos com relação aos valores nutricionais dos alimentos e da saúde humana. Entretanto, estudos apontam reações adversas aos aditivos sintéticos, tais como reações tóxicas e o possível desenvolvimento de cânceres específicos. A busca por agentes antimicrobianos naturais em alternativa aos conservantes sintéticos tem sido constante; a fim de proporcionar o controle microbiológico e a extensão da vida de prateleira, excluindo, portanto, as desvantagens trazidas pelo uso de aditivos artificiais, através de ação antimicrobiana de óleos essenciais. O objetivo do trabalho foi verificar a ação antibacteriana dos óleos essenciais de café verde e torrado (Coffea arabica), cacau (Theobroma cacao), casca e folha de canela-do- -Ceilão (Cinnamomum zeylanicun) sobre as bactérias Bacillus cereus, Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Salmonella Enteritidis e Salmonella Typhimurium. Os óleos essenciais foram impregnados em discos de papel filtro de 6 mm de diâmetro, próprios para antibiograma; sendo posteriormente colocados em placas de Petri contendo Ágar Nutriente previamente semeado com os micro-organismos. As mesmas foram incubadas a 35°C por 24 e 48 horas. Após este período foi possível observar e medir o diâmetro dos halos e, halos iguais ou superiores a 10 mm foram considerados significativos de atividade antimicrobiana. Os óleos essenciais de cacau, canela casca e canela folha inibiram significativamente todos os micro-organismos testados. E. coli foi inibida significativamente por todos os óleos essenciais. O óleo essencial de canela casca demonstrou os melhores efeitos inibitórios, sendo o mais significativo sobre a E. coli (halo de 36 mm).(AU)

Validation of food-grade salts of organic acids as ingredients to control Listeria monocytogenes on pork scrapple during extended refrigerated storage.

This study was conducted to investigate control of Listeria monocytogenes on pork scrapple during storage at 4°C. In phase I, scrapple was formulated, with or without citrate-diacetate (0.64%), by a commercial processor to contain various solutions or blends of the following antimicrobials: (i) lactate-diacetate (3.0 or 4.0%), (ii) lactate-diacetate-propionate (2.0 or 2.5%), and (iii) levulinate (2.0 or 2.5%). Regardless of whether citrate-diacetate was included in the formulation, without the subsequent addition of the targeted antimicrobials pathogen levels increased ca. 6.4 log CFU/g within the 50-day storage period. In the absence of citrate-diacetate but when the targeted antimicrobials were included in the formulation, pathogen numbers increased by ca. 1.3 to 5.2 log CFU/g, whereas when citrate-diacetate was included with these antimicrobials, pathogen numbers increased only by ca. 0.7 to 2.3 log CFU/g. In phase II, in the absence of citrate-diacetate, when the pH of the lactate-diacetate-propionate blend (2.5%) was adjusted to pH 5.0 or 5.5 pathogen numbers remained unchanged (≤0.5 log CFU/g increase) over 50 days, whereas when citrate-diacetate was included with the lactate-diacetate-propionate blend adjusted to pH 5.0 or 5.5, pathogen numbers decreased by 0.3 to 0.8 log CFU/g. In phase III, when lower concentrations of the lactate-diacetate-propionate blend (1.5 or 1.94%) were adjusted to pH 5.5, pathogen numbers increased by ca. 6.0 and 4.7 log CFU/g, respectively, whereas when the mixture was adjusted to pH 5.0, pathogen numbers increased by ≤0.62 log CFU/g. Thus, scrapple formulated with lactate-diacetate-propionate (1.5 and 1.94% at pH 5.0) is an unfavorable environment for outgrowth of L. monocytogenes.

Estimate of intake of sulfites in the Belgian adult population.

An exposure assessment was performed to estimate the usual daily intake of sulfites in the Belgian adult population. Food consumption data were retrieved from the national food consumption survey. In a first step, individual food consumption data were multiplied with the maximum permitted use levels for sulfites, expressed as sulphur dioxide, per food group (Tier 2). In a second step, on the basis of a literature review of the occurrence of sulfites in different foods, the results of the Tier 2 exposure assessment and available occurrence data from the control programme of the competent authority, a refined list of foods was drafted for the quantification of sulphite. Quantification of sulphite was performed by a high-performance ion chromatography method with eluent conductivity detector in beers and potato products. Individual food consumption data were then multiplied with the actual average concentrations of sulfite per food group, or the maximum permitted levels in case actual levels were not available (partial Tier 3). Usual intakes were calculated using the Nusser method. The mean intake of sulfites was 0.34 mg kg(-1) bw day(-1) (Tier 2), corresponding to 49% of the acceptable daily intake (ADI) and 0.19 mg kg(-1) bw day(-1), corresponding to 27% of the ADI (partial Tier 3). The food group contributing most to the intake of sulfites was wines. The results showed that the intake of sulfites is likely to be below the ADI in Belgium. However, there are indications that high consumers of wine have an intake around the ADI.