Center for Food Safety & Applied Nutrition FDA Technical Bulletin Number 5 |
A. METHOD FOR APPLE PRODUCTS (V-42)
This method describes procedures for:
Dried apple slices or chops are covered in Section 9.F., Dried Fruits.
Generally, in most pulped or extracted apple products, defective material is reduced to microscopic size, which requires analysis by digestive flotation separation procedures and by mold mycelia count techniques described in AOAC.
Most apple varieties are derived from Malus sylvestris Mill., of European and Western Asian origin, but some have originated through hybridization with other species of Malus. Apple butter is made by boiling down apples with sugar and spices. Apple pomace (cider press cake) is the solid residue remaining when raw apples are crushed and 80-90% of the fruit is pressed or extracted into juice. Apple pomace is used as a source for the manufacture of pectin; or the dried pomace residue can be fed to livestock. Nearly all known apple varieties have been used for apple juice. In order to obtain the desired flavor in the finished product, the common practice is to use a blend of two or more varieties.
b. Fungal Deterioration and Moldiness -- Deficiencies in handling and storage may promote the development of rot-producing fungi. A small amount of rot may produce a musty taste in a large amount of apple juice. Blue mold rot, caused by Penicillium expansum, is the most common and destructive. Brown rot, caused by Monilinia fructicola (Wint.) Honey, is found in all producing areas in the Eastern United States. Neofabraea perennans and N. malicorticis cause bull's-eye rot, especially in the Pacific Northwest. Black rot, caused by Physalospora obtusa, is common east of the Rocky Mountains. Mycosphaerella pomi, which causes fruit spot, is most destructive in New England, appearing in orchards which have not been properly sprayed.
b. Mold Count -- Use AOAC 975.51.
Weigh 200 g pomace in a tared 1500 mL beaker and add 1000 mL water. Heat to boiling and simmer 2 hr. Add sufficient water to bring mixture to the original volume. Pulp through laboratory cyclone [945.75B(g)] and mix thoroughly. Weigh 50 g stabilizer solution [III. (15)] in a 250 mL beaker and add 50 g of the pulp. Mix thoroughly and make mold count as directed in AOAC 965.41.
b. Analysis for (Geotrichum) Mold -- Measure subsample up to 1 L and follow AOAC 974.34, reporting numbers of mycelial fragments per sample volume.
B. METHOD FOR DECOMPOSITION IN BLACKBERRIES, RASPBERRIES, AND OTHER DRUPELET BERRIES (V-44)
This method is limited to a macroscopic procedure for the determination of decomposition in drupelet berries, including fruits of this type known as bramble berries or caneberries. The method is applicable to frozen and canned whole berries and provides, as necessary, information relative to the extent of decomposition in the fruit to supplement that provided by the mold count method for measuring decomposition.
b. Insect Infestation and Damage -- There are a number of insect pests that may invade the fruit. Raspberry fruitworms are beetle larvae which penetrate the flower buds and developing fruit. Common species are the western raspberry fruitworm (Byturus bakeri Barber) and the eastern raspberry fruitworm (B. rubi Barber). Redberry mite (Acalitus essigi (Hassan)), which is common in the Pacific Coast area, produces "redberry disease" by feeding around the base of the drupelets, causing the fruit to become brightly colored and hard. Drupelet berries are sometimes infested by field insects such as thrips, which occur in large numbers. Drosophila flies may be attracted to overripe and sour fruits. AOAC methods are available for the determination of insect contamination.
(ii) Frozen berries -- Each subsample (representing one barrel, 30-lb can or other large container) should consist of about 3 quarts of berries. Thaw and mix the 3 quarts to make one composite analytical unit. Mix thoroughly without damaging the berries. If the berries are in consumer size packages (12-16 oz.), thaw and thoroughly mix four such packages from the same code to make one composite analytical unit. Divide the composited unit, including juice, into two unequal portions: one of about two-thirds of the volume to be used for the mold count and one of about one-third of the volume to be used for visual examination.
b. Visual Examination - Drain the berries (for frozen berries, use the second, smaller portion of the analytical unit) on a No. 20 sieve and wash with water. Immerse berries in water in large white pan and keep all berries immersed during examination. Repeat washing if water is not fairly clear. Examine each berry under water in strong light. Pick out as rotten those berries and fragments which have at least 5 drupelets containing either external or internal mold or both. External mold may show hyphal masses extending from the fruit. Internal mold will discolor and affect the brightness of the individual drupelet. Confirm all questionable rot spots by examining a fragment of the tissue for mold under a compound microscope. Classify the tissue as rotten only when a substantial number of mold filaments are present (see Chapter IV, Special Techniques). Drain the good and the rotten berries separately for 2 min on a 5-in. No. 20 sieve. Weigh the good and the rotten berries.
c. Mold Count -- Follow AOAC 955.47
d. Report -- Tabulate results as follows:
Code No. _______ | Barrel or Sub. No. | ||||
1 | 2 | 3 | etc. | Average | |
Total wt of drained Berries (g) | |||||
Drained wt of good berries (g) | |||||
Drained wt of rotten berries (g) | |||||
Percent of rotten berries | |||||
Percent of mold count | |||||
Remarks: |
C. METHOD FOR DECOMPOSITION IN BLUEBERRIES(V-46)
This method is limited to a macroscopic procedure for the determination of decomposition in blueberries. The method is applicable to frozen and canned whole blueberries and provides, as necessary, information relative to the extent of decomposition in the fruit to supplement that provided by the mold count method for measuring decomposition.
b. Moldiness and Fungal Deterioration -- Blueberries are subject to attack by many species of fungus both before and after harvest. Molds primarily affect wild berries rather than cultivated berries because growers have greater difficulty controlling natural sources of contamination in the wild berries.
(ii) Frozen blueberries -- Thaw the frozen berries in original containers, as appropriate. In containers larger than a No. 2 can, remove a No. 2 canful or 20 oz. If smaller, examine each subsample separately. Do not drain but proceed as in (i) above, beginning "Weigh a 40 g. . .". Save the larger portion for the mold count.
b. Visual Examination -- Examine each blueberry under water, using a strong light. Separate the rotten from the good berries. Decayed tissue can be identified as it resists bleaching. Confirm all questionable rot spots by examination of a small piece of the tissue for mold, using the compound microscope. Classify the tissue as rotten only when a substantial number of mold filaments are present. Classify as rotten any blueberry in which the rot affects 1/4 or more of the surface area. Count the number of rotten berries found in each subsample.
c. Mold Count -- Make mold counts as follows:
(ii) Blueberries Frozen with No Added Sugar -- Pulp the larger portion retained from a.(ii) through a laboratory cyclone [AOAC 945.75B(g)]; dilute with a stabilizer and make mold count as in (4)c.(i) above.
(iii) Blueberries Frozen with Sugar or Syrup -- Berries frozen with sugar or syrup may not yield a satisfactory pulp for mold counting without cooking. Boil the retained blueberries from (4)a.(ii) for 5 min or until tender. Pulp the sample while hot, dilute with stabilizer solution and make mold count as in (4)c.(i) above.
d. Report -- Tabulate results as follows:
Code No. _____ | Subsample No. | ||||
1 | 2 | 3 | etc. | Average | |
Total No. of Berries | |||||
No. of Rotten Berries | |||||
Percent Rotten Berries | |||||
Percent Mold Count | |||||
Remarks: |
D. METHOD FOR CHERRIES(V-48)
This method describes procedures for sample preparation and visual examination to determine the
Other insects which may damage the fruit include cherry fruitworm (Grapholita packardi Zeller), pandemis moth [Pandemis albaniana (Walker)], destructive pruneworm [Mineola scitulella (Hulst)], Syneta leaf beetle [Syneta albida (Le Conte)], cherry curculio [Tachypterellus consors cerasi (List)], plum gouger [Coccotorus scutellaris (LeConte)], and plum curculio [Conotrachelus nenuphar (Herbst)].
b. Moldiness and Fungal Deterioration -- Cherries may rot as a result of injuries received before or after harvesting or because of delays in processing. Since blemishes may sometimes resemble rot, microscopic examination to determine the presence of mold may be required. Cherries to be used in brining are generally harvested prior to being fully matured in color and texture. Thus, no method is needed for determination of rot in brined and maraschino cherries. Fungus diseases and their causative organisms include brown rot [Monilinia fructicola (Wint.) Honey], Rhizopus rot (Rhizopus nigricans), Cladosporium rot or green mold (Cladosporium sp.), blue mold rot (Penicillium sp.) gray mold rot (Botrytis sp.), and alternaria rot (Alternaria sp).
b. Visual Examination -- Cut open each cherry and examine under good lighting with 10X magnification, as necessary to show extent of damage. Classify and count damaged cherries in accordance with the three reject categories listed in reporting table (c).
c. Report -- Tabulate results as follows:
Code No. ______ | Subsample No. | ||||
1 | 2 | 3 | etc. | Average | |
Total No. examined | |||||
No. with Maggot(s) present | |||||
No. with Maggot Mouth Hooks Present | |||||
No. with Maggot Tunneling Covering 1/4 or More of Pit Area | |||||
Total No. of Rejects | |||||
Percent of Rejects | |||||
Remarks: |
b. Classification of Reject Cherries -- Reject cherries should be classified as follows:
(ii) Insect-Damaged -- Any cherry containing one or more whole or equivalent insects.
c. Visual Examination -- Examine each cherry under good lighting for mold or insects visible to the naked eye, or with such magnification as necessary in any particular case. If the magnification exceeds 10X, this should be stated in the report of results. Cut open any cherry as necessary to expose damage by mold or insects. Classify and count cherries in each reject category.
d. Report -- Tabulate results as in (4)c., substituting the appropriate savect categories.
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