Numerical method for prediction of final microbial load in inoculated cylindrical cans of tomato concentrate heated in a pilot plant

A finite difference numerical method to predict temperatures and destruction of a thermally labile species in cylindrical cans of conduction heating food was applied to compute final microbial load in an inoculated 18°Brix canned tomato concentrate at pH = 4.5 processed under conditions simulating industrial practice. Predictions of product temperature and final microbial load in three can sizes compared well with experimental heat penetration data and estimation of surviving species of Bacillus coagulans ATC 8038 spores inoculated into the cans. The application of the model as an aid to establishing process schedules is illustrated for a can with a required IS¹⁴₁₀₀= 11.44 min. The model predicts that a 29.5 min heating time at 105.6°C would provide an IS¹⁴₁₀₀= 11.77 min.     

Effect of the Parabens With and Without Nitrite on Clostridium botulinum and Toxin Production in Canned Pork Slurry

Antimiciobials were evaluated in thioglycollate broth at pH 6.5 for the ability to inhibit growth and toxin production by C. botulinum 12885A and ATCC 7949 (Type B). Methyl, ethyl, propyl, and butyl parabens (0.1%) and sorbic acid (0.2%) were effective in inhibiting growth of C. botulinum 12885A and ATCC 7949 in broth. Ethyl, propyl, and butyl parabens (0.1%) and sorbic acid (0.2%) inhibited toxin production by both strains in culture medium. Ethyl, propyl, butyl parabens (0.1%) and sorbic acid (0.2%) were individually added to a comminuted pork slurry having salt and sugar, with or without 40 ppm sodium nitrite. Cans were inoculated with a mixture of C. botulinum 12885A and ATCC 7949 spores. The canned product was abused by holding at 27°C and was observed over a 3-month period for swollen cans. Swollen cans were examined for botulinal toxin by the mouse bioassay. Propyl and butyl paraben did not inhibit or delay toxin production. Ethyl paraben with or without nitrite delayed toxin production for 4 wk. Sorbic acid inhibited toxin for 3 wk; when 40 ppm nitrite was added to the sorbic acid treatment, toxin production was delayed for 4 wk.     

Control of Spoilage of Canned Mushrooms Inoculated with Clostridium sporogenes PA3679 Spores by Acid-Blanching and EDTA

A new process involving blanching in 0.05M citric acid and addition of 200 ppm CaNa₂EDTA in the canning brine (ABC) was compared to the standard commercial method (SCM) for control of spoilage of canned mushrooms inoculated with C. sporogenes PA3679 spores. Fresh mushrooms were uniformly inoculated by vacuum hydration in spore suspensions. Compared to the SCM, the ABC process reduced the potential number of nonsterile units per million cans at F_o 10 from 14.8 to 2.1. At F_o 8 and 10, the ABC process reduced spoilage of the canned products from 100 to 68.1% and 89.3 to 28.7%, respectively, compared to the SCM.     

Evaluation of dairy powder products implicates thermophilic sporeformers as the primary organisms of interest

Dairy powder products (e.g., sweet whey, nonfat dry milk, acid whey, and whey protein concentrate-80) are of economic interest to the dairy industry. According to the US Dairy Export Council, customers have set strict tolerances (<500 to <1,000/g) for thermophilic and mesophilic spores in dairy powders; therefore, understanding proliferation and survival of sporeforming organisms within dairy powder processing plants is necessary to control and reduce sporeformer counts. Raw, work-in-process, and finished product samples were collected from 4 dairy powder processing facilities in the northeastern United States over a 1-yr period. Two separate spore treatments: (1) 80°C for 12 min (to detect sporeformers) and (2) 100°C for 30 min (to detect highly heat resistant sporeformers) were applied to samples before microbiological analyses. Raw material, work-in-process, and finished product samples were analyzed for thermophilic, mesophilic, and psychrotolerant sporeformers, with 77.5, 71.0, and 4.6% of samples being positive for those organisms, respectively. Work-in-process and finished product samples were also analyzed for highly heat resistant thermophilic and mesophilic sporeformers, with 63.7 and 42.6% of samples being positive, respectively. Sporeformer prevalence and counts varied considerably by product and plant; sweet whey and nonfat dry milk showed a higher prevalence of thermophilic and mesophilic sporeformers compared with acid whey and whey protein concentrate-80. Unlike previous reports, we found limited evidence for increased spore counts toward the end of processing runs. Our data provide important insight into spore contamination patterns associated with production of different types of dairy powders and support that thermophilic sporeformers are the primary organism of concern in dairy powders.     

Bisphenol A (BPA) and its source in foods in Japanese markets

The determination of bisphenol A (BPA) and/or bisphenol A diglycidyl ether (BADGE) in foods sold in Japanese markets and in water leached from six epoxy resin cans with similar diameters was carried out using high-performance liquid chromatography (HPLC) with electrochemical detection (LC/ECD), LC-mass spectrometric detection (LC/MS) and LC-tandem mass spectrometric detection (LC/MS/MS). BPA concentrations were 0-842 ng g^-1 for 48 canned foods, 0-14 ng g^-1 for 23 foods in plastic containers, and 0-1 ng g^-1 for 16 foods in paper containers. No BADGE was detected in three canned foods. There was no difference in leaching concentrations of BPA into glycine buffers at pHs 8 and 11, and water. The amounts of BPA leached into water from six epoxy resin cans held at 121°C for 20 min were almost the same as the cans' contents and were much higher than the amounts leached from cans held at or below 80°C for 60 min. The amount leached depended on the type of can, but not on the amount of BADGE leached from the cans. Considerably more BPA than BADGE leached to water from six cans. Two cans whose contents had high concentrations of BPA showed no BADGE leaching even at 121°C, suggesting the different kinds of epoxy resin can linings from others. The results imply that the main source of human exposure to BPA is food from cans with linings that contain high percentages of BPA as an additive or an unforeseen contaminant.     

Factors influencing the migration of bisphenol A from cans

The objective of this study was to determine whether there is a relationship between bisphenol A (BPA) migration from metal cans and container contents (glucose, sodium chloride, and vegetable oil), heating time, and/or temperature. Cans containing 5 to 20% glucose solution, 1 to 10% sodium chloride solution, and vegetable oils (corn, olive, and soybean oil) were heated at 121 degrees C for 30 min. Water samples were heated at 105 degrees C for 30 min and at 121 degrees C for 15, 30, and 60 min, respectively. In the test involving water samples, it was found that temperature's effect on BPA migration from cans can be more extensive than that of heating time. When cans were heated at 121 degrees C, the presence of 1 to 10% sodium chloride or vegetable oils greatly increased the migration of BPA from the cans. Moreover, the presence of 5 to 20% glucose in cans heated to 121 degrees C resulted in increased BPA migration relative to that for water controls.     

Migration of bisphenol A (BPA) from can coatings into a fatty-food simulant and tuna fish.

The effect of heat processing, storage time and temperature on the migration of bisphenol A (BPA) from organosol and epoxy can coatings to a fatty-food simulant and tuna was determined. Analyses of BPA were performed by RP-HPLC with fluorescence detection. Four migration experiments, performed between 2000 and 2003, using cans with organosol, epoxy and a combination of both types of coatings were performed under different processing conditions and storage times. Migration levels as high as 646.5 microg kg(-1) BPA from an organosol coating of tuna fish cans were found using a fatty-food simulant following the heat processing of the simulant-filled cans. Levels ranging from 11.3 to 138.4 microg kg(-1) BPA from tuna cans coated with an epoxy resin migrated to the fatty-food simulant during 1 year at 25 degrees C. Levels of BPA migration into a fatty-food simulant from thermally processed and stored tuna cans coated with a combination of organosol and epoxy resins and from vegetable cans coated with an epoxy resin were below the limit of quantitation of 10.0 microg kg(-1). Migration of BPA to tuna ranged from <7.1 to 105.4 microg kg(-1) during long-term storage at 25 degrees C. BPA levels in tuna cans purchased from three local supermarkets ranged from <7.1 to 102.7 microg kg(-1). The highest migration levels were found following heat processing at temperatures as high as 121 degrees C and at times as long as 90 min. Coatings from different can batches can give different levels of BPA migration. The migration levels of BPA found in this work are below the present European Union migration limit, except the 646.5 microg kg(-1) found after the commercial heating process was applied to the simulant-filled cans coated with the organosol resin.     

Causes of spoilage of thermally processed fish in Morocco

Of 946 cans of fish suspected of being spoiled, which were collected from local stores and canneries in Morocco, 484 cans (51%) had major container defects. Leaking seams at the manufacturer's end and droops and vees on the canner's end were the most prevalent defects (36 and 28%, respectively). Upon microbiological analysis of 256 cans, viable micro-organisms were recovered from 168 cans, of which 72% contained typical leaker spoilage organisms, while 28% contained typical underprocessing spoilage organisms. Thermophilic organisms were found in association with other organisms in half of the cans. The more severe the swell, the greater were the chances of recovering micro-organisms. The scoring system of Davidson & Pflug (1981) indicated that 16% and 71% of the cans had seams of questionable and poor quality, respectively, and these had a potential for leakage. The most probable cause for spoilage was determined: leakage, 80%; non-microbial swells, 10%; underprocessing, 10%.     

三片食品罐外壁涂膜中有害物质向内涂的迁移

对制版印刷后的食品用三片金属罐外壁涂料中三聚氰胺、苯、甲苯3种有害物质在堆码过程中从外壁涂膜向内涂膜的迁移扩散进行研究。采用高效液相色谱法检测3种常用金属罐(番茄酱罐、八宝粥罐、凉茶罐)内壁和外壁涂膜中三聚氰胺、苯和甲苯3种残留物在去离子水、3g/100mL乙酸、体积分数10%乙醇3种水性食品模拟液中的初始迁移量。并对制罐铁片在恒温(30℃)、恒湿(60±2)% RH、恒压34kPa条件下堆码2个月后内壁涂膜中3种残留物的向食品模拟液中的迁移量与堆码前进行比较分析,即外壁涂膜中这3种残留物向内壁的迁移扩散情况。结果表明,3种有害物质均有从外壁向内壁迁移的现象,迁移量达到0.04～1.60μg/mL,对内壁涂膜的安全性造成极大影响,严重影响到罐装食品的安全性。     

Cause of bisphenol A migration from cans for drinks and assessment of improved cans

In the previous investigation, we found that some cans for coffee and black tea drinks released large amounts of bisphenol A (BPA) into their contents. Equivalent cans were obtained and the cause of BPA migration was investigated. Equivalent cans A, B and D contained high levels of BPA in the side seam, in the bottom, and in the bottom and the side seam, respectively, while can C contained some level of BPA in the body, which has a large area, therefore, all of them contained high amounts of BPA in their coatings. In the migration test, there was no BPA migration from the cans into water at 60 and 95 degrees C for 30 min, into 20% ethanol at 60 degrees C for 30 min, or into n-heptane at 25 degrees C for 60 min. However, at 120 degrees C for 30 min, equivalent cans released 35-124 ng/mL BPA into the water. The total migration was similar to the total residues of BPA in the can coating and was close to the total amount of BPA in the drinks. Thus, BPA migration from the can coating requires heating to more than 105 degrees C, which is the glass transition temperature of the epoxy resin. Improved cans which contained less than 1/10 as much BPA as the equivalent cans showed very low migration levels, i.e., 3-6 ng/mL.     

Modified Spore Inoculation Method for Thermal-Process Verification of Pinto Beans and Green Beans Canned in Two Large Reusable Containers

As an alternative to standard metal cans, 2 large, reusable containers with volumetric capacities 3.6 to 3.8 times larger than a standard #10 can were constructed of nickel‐plated steel. Process times and cold point determinations were previously determined using mathematical approximations of heat‐penetration data. It was necessary to verify the adequacy of these process times using inoculated containers. Because it was impractical to use traditional inoculated can procedures, a modification was developed using spores of Clostridium sporogenes PA3679 immobilized in alginate beads contained in brass tubes. Adequacy of the calculated thermal processes was demonstrated; no viable anaerobic spores survived in the inoculated packs.     

Determination of a process time for a new product: canned low acid artichoke hearts

In order to obtain a process time for canned low acid artichoke hearts, the heat resistance of Clostridium sporogenes PA 3679 in phosphate buffer (pH 7) and in artichoke puree (pH 5.2) was determined in the range of 100–118°C. D _T values in artichoke puree were determined by the most probable number and plate count methods. D _121°C values were deduced by extrapolation of the curves. An F 8.3/121 (see nomenclature section) target value of 1.8 min, equivalent to an F ₀= 2.5 min, was established considering a D _121°C value of 0.36 min for artichoke puree. The cold point for canned artichoke hearts in 1/2 kg (71.5x117 mm) cans was determined, a set of heat penetration and cooling curves were obtained and the values of the parameters ' j ' and ' f ' were found. A process time was deduced, 21.5 and 23 min of heating at 121°C, following the methods of Patashnik (1954) and Hayakawa (1970, 1974) respectively, in order to reach the F ₀ target of 2.5 min for this new canned food. This process was adequate, as the inoculated experimental pack test showed no altered cans out of 50 inoculated after 21.5 min of heating at 121°C.     

Migration of bisphenol A from can coatings—effects of damage, storage conditions and heating

Bisphenol A (BPA) is an important monomer used in the manufacture of epoxy resins for internal food can linings. Experiments were conducted to investigate the effects of different storage conditions and can damage on the migration of BPA to foods. These experiments were conducted in a systematic fashion by filling empty epoxyphenolic coated cans with four foods: soup, minced beef, evaporated milk and carrots and a food simulant (10% ethanol). Filled cans of each food type or simulant were then sealed and processed using appropriate conditions, before storage at three different temperatures: 5°C, 20°C and 40°C. For each of the storage regimes, 50% of the cans were dented to establish if this would lead to increased BPA migration. Cans were removed from these stocks at intervals of 1, 3 and 9 months storage at 5°C and 20°C or 10 days, 1 and 3 months at 40°C. Some initial problems of heterogeneity between samples was overcome by determining the amount of BPA in food as well as in the can lining. It was found that 80-100% of the total BPA present in the coating had migrated to foods directly after can processing by pilot plant filling with food or simulant, sealing and sterilization. This level was not changed by extended storage (up to 9 months) or can damage, indicating most migration was occurring during the can processing step. There was no noticeable difference, in this respect, between the different foods or the food simulant. Analysis of control samples (foods fortified with ∼0.1 mg kg^-1 BPA and contained in Schott bottles) showed that BPA was stable under both processing and storage. Experiments were also conducted to investigate the potential effects, on the migration of BPA from can coatings, of cooking or heating foods in the can prior to consumption. Food cans were purchased and the food either cooked or heated in the can. BPA was analysed prior to and after the heating/cooking process. It was concluded from the results that there were no appreciable differences in the BPA level before and after cooking or heating.     

Monitoring of bisphenol-A-diglycidyl-ether (BADGE) in canned fish in oil

A survey at the European level was initiated on the quantification of bisphenol-A-diglycidyl-ether (BADGE) in canned fish in oil in order to assess the exposure of BADGE. A total of 382 canned fish samples were collected from all 15 Member States and Switzerland and analysed for BADGE in fish. The fish was extracted first with hexane and reextracted with acetonitrile, followed by a membrane filtration and reverse phase HPLC analysis with fluorescence detection. The analysis of the fish showed that about 3% of the samples contained BADGE at a level above 1mg/kg. The samples exceeding the limit by a larger margin were mostly from anchovy cans and cans manufactured in 1991-1995.     

THERMAL DESIGN PROCESS FOR ACIDIFIED CANNED PAPAYA (Carica papaya L.) PULP

Previous results showed that the heat resistant portion of pectinesterase in the acidified papaya pulp var. “formosa” presented greater thermal resistance than Cl. pasteurianum. Based on this, and determined F^7.8C_77C, a value of 12.3 min was calculated using the heat resistant portion of pectinesterase as the target for the process, and applying 1.7 decimal reduction of the activity of the heat resistant enzyme (98% inactivation). Using Shiga (1976) an empirical relationship and a heating time of 12.9 min in water bath at 97C was established for the process. Three processing tests were carried out under these conditions using 6 cans per test. The processing values varied from 12.33 to 12.75 min at 77C. Statistical analysis showed no significant difference between tests and among cans as well as test at the 0.05 and 0.01 α level. After processing the cans, gelatinization, activity of remaining enzyme and micro-organism growth were not detected. This shows that the process was able to inactivate the heat resistant portion of pectinesterase and kill the natural micro-flora present on the pulp. By considering the initial variation of the pectinesterase activity in the pulp and F^7.8C_77C - value of 16.7 min, a safety factor for the process was applied. This process was equivalent to 15 min of heating in water bath at 97C and corresponded to 2.3 decimal reductions in activity of heat resistant pectinesterase. An inoculation pack study was performed to verify the microbiological safety of such process. Each can of papaya pulp was inoculated with 1 mL of a 10⁴ spore/mL suspension of Cl. pasteurianum. Swelling of the cans, growth after subculturing and pectinesterase were not detected after incubation, showing that the pulp could be safely processed. The storage test showed no significant changes in the color, flavor, aroma and texture of the canned acidified papaya pulp.     

Influence of Sodium Tripolyphosphate on the Binding and Antimicrobial Properties of Reduced NaCl-Comminuted Meat Products

The binding and antimicrobial properties of comminuted meat products were evaluated at varying levels of NaCl and of sodium tripolyphosphate (STPP). The meat batters were inoculated with Clostridium sporogenes spores (10/g) either before (cans) or after (vacuum packages) thermal (70°C) processing. Product binding was inferior when the NaCl level was reduced to 1.1% (50% reduction). STPP increased pH by 0.17-0.23 units and restored binding of low NaCl products. During storage (20°C) microbial growth and product spoilage were more rapid with decreasing brine level, irrespective of presence or absence of STPP.     

Can Fitting in Green Beans: Effect of Growing Season, Base Steel Composition, Tinplate Thickness, Can Vacuum and Storage Conditions

Spring and fall grown green beans were packed under high and low vacuum conditions in high and low residual Al, Ni, Cu, Si, S, and Mn base steel .25 and .50 electrotin plated J-enamel cans and evaluated during storage at 38°C and room temperature for pitting on and under the s deseams. Cans containing spring grown beans were more severely pitted than those of the fall pack. High residual (0.061%) Cu steel cans were more severely pitted than other treatments. The .25 electrotin plated cans were more severely pitted in high Cu residual cans, as were the low vacuum spring pack cans at 38°C storage.     

食品金属罐中14种双酚类物质迁移量的同时测定及杀菌过程对其迁移的影响

为了调查国内食品金属罐中双酚类物质的迁移水平,本文建立了同时测定食品金属罐中14种双酚类物质迁移量的高效液相色谱法,并研究了杀菌过程对双酚类物质迁移的影响及食品金属罐中双酚类物质的迁移规律.结果表明,14种双酚类物质在4种食品模拟物(4％体积乙酸、10％体积乙醇、50％体积乙醇和异辛烷)中线性关系良好,加标回收率为83...     

THE EFFECT OF THERMOCOUPLE AND RECEPTACLE TYPE ON OBSERVED HEATING CHARACTERISTICS OF CONDUCTION-HEATING FOODS PACKAGED IN SMALL METAL CONTAINERS

Three different types of thermocouples and receptacles were studied to determine the effect on the observed heat penetration rate of a conduction‐heating food packaged in 202 × 204 and 211 × 300 cans. The studies were conducted at two product initial temperatures (70 and 140F) and three retort temperatures (240, 250 and 260F) using an Allpax R&D retort. The results indicated that the Ecklund stainless steel receptacles and needle type thermocouples in 202 × 204 cans increased the apparent heat penetration rates significantly, which resulted in underestimated Ball Formula process times (≈5%) and overestimated process lethalities (≈27%). However, in the 211 × 300 cans only minimal effects were seen on the apparent heat penetration rates, Ball process times and resulting lethalities. The use of plastic Delrin receptacles and thermocouples in 202 × 204 and 211 × 300 cans produced results in close agreement with those obtained from thin‐gauge flexible thermocouples having minimum conduction error.     

Antibotulinal Activity of Methyl and Ethyl Fumarates in Comminuted Nitrite-Free Bacon

Mono- and dimethyl and ethyl esters of fumaric acid were evaluated for their antibotulinal efficacy in cans of comminuted nitrite-free bacon. At 0.125%, all were equal or superior to 120 ppm nitrite in preventing toxin formation in cans incubated at 30°C for 8 wk. No cans swelled or became toxic when mono- or dimethyl fumarate was added. With monoethyl fumarate, two cans out of twenty swelled but were nontoxic. The least effective ester was diethyl fumarate but its activity was equal to that of 120 ppm nitrite.